· p r e f a c e. n the accompanying treatise we have endeavoured to give the general results of...
TRANSCRIPT
The investigations , the resul t o f w hich are published in the present volume have been carried on by
con tributions from the N orwegian governmen t and The JOA CIIIM F auna: F und of the Bergen Museum . The report is publ ished at the expense of the latterfund and o. the Ennnm SM T and the DAN IE LSSEN Fun d s or the Museum .
P R E F A C E .
N the accompanying treatise we have endeavoured to give the general results of our observations on the Hydrography and Pelagic
Li fe of the Northe rn Ocean,obtained
,of late years
,dur ing our Mar ine -Biological i nvestigation s . More detail ed resul ts oi our
observation s in Norwegian waters,and the Herring Fishery carried on therein
,we reserve for future publ ication .
Materi al s for our treati se have also been obtained through the kind assi stance of various publ ic in stitutions and private
individuals , and the help thusafforded us i s Special ly alluded to in our work .
We des ire to expres s our thanks to the Officers of the Royal Norwegian Navy , the Meteorological Institute , the Geographical
Surveying Board , the Directors of the Bergen Museum ,and to al l those Shipowners and Masters of vessel s who have accorded us their
valuabl e assi stance .
June 1 898.
Johan Hjort. H. H. Gran .
I. The Hydrographical Conditions of the Northern Ocean.
greatest part of the Northern Ocean i s a deep -water sea .
e 1 000 metre curve , i n many places approaches n igh to theNorwegian coast (as for instance at Storeggen ofi
'
Kristianssund ,
and at Vesteraalseggen) . From these points,and across tO ' Ice
l and , Jan Mayen and Greenland , the depth exceeds 1 000 fathoms .Throughout thi s deep -water sea
,the physical conditions at the
bottom are very uniform,and of an Arctic character .
If one fol lows the 400 metre curve on the Chart o f Depths,
Pl . 1 one wil l find the boundary of the Norwegian “ coastal bank s ” .
It will be perceived that the sea - bottom beyond them descends almostperpendicularly downwards
,so that the banks themselves form a
sort of barrier or breast work to the Norwegian coast . It wil lfurthermore be seen that thi s barri er extends from off the SogneFj ord to the shores of Scotland
,and that the whol e of the North
Sea i s thus of a depth,and similar physical cond ition s to the banks .
In order to understand the physical conditions of these banks—our especial subj ect one must , above all , remember , that thelatter are quite i sol ated from the cold polar water of the deepersea . The water which covers our coastal bank s comes from thesouthward , and i s carr ied on to our shores by the wel l knownAtlantic current the Gul f Stream which
,in the area
comprised within a l ine from Scotland to Iceland and F inmarken,
covers the central portion of the surface of the Northern Ocean,
and , down in the deep , spreads i tself over the banks , the NorthSea , the Skagerak , and up to the Swedish Coast and mouth of theChri sti ania Fj ord .
From Pl . 2 , i t wil l be seen that the greates t porti on of thesurface of the Northern Ocean i s occupi ed in summer by watercontaining over 35 of salt .
In l ike manner the bottom from “Eggen in to the coast i scovered with water
,the sal in ity of which i s 3 5 of a temperature
ranging from 6° to 70 Cel sius . Only bel ow “Eggen ” wil l a lowertemperature be found
,down to - 1 0 at a depth of 900 metres
,
where the,
sal inity i s al so less , as the water i s mixed with thatfrom the polar ice . In on the coast the sal ini ty
,too
,decreases
,
as will be seen from the plate,and therefore one can lay down 3
deep regions according to the physical condition s :1 . The Arctic Sea Region at the greatest depth .
2 . The warm Atlantic Ocean Region .
3 . The Coastal Water Region .
A general vi ew of the layers of water to be met with on,and
off our Northern Ocean seaboard,wil l be best seen from the hydro
graphic section which was obtained,through the kindness of the
Geografiske Opmaaling (Geographical Survey) , off H ustadviken, wherethe decl ivity towards the great depths
,Storeggen, IS comparatively
near land . The section i s given on Pl . 5 , Fig . 2.
The same layers of w ater which are met with,the one below
the other along the coast , appear on the surface of th e sea whenfar off the land . The hvdrographic profil e from the Sogne Fjordto the Arctic Ocean
,Pl . 4
,Fig. 1
,thus shews that the sal t Atlantic
water fil l s the enti re central portion of the Northern Ocean fromthe surface downwards to a depth of at l east 300 metres (dur ingthis expedi tion deeper inv estigations were not insti tuted) . The Arcti cwater
,wi th its l esser sal in i ty
,shoves i tsel f l ike a col d wedge across
the Gulf Stream,and in the Arctic Ocean i s met wi th from the
surface to the greatest depths .The thickness of the coastal water vari e s greatly with the
season s . In the winter i t can form a l ayer up to 250 metres inthickness , whi lst in summer the Atlantic water may be met w ith ,close in to land
,at a depth of 40 to 50 metres .
On Pl . 5 , Figs . 3 and 4 , w il l b e found a representation of theannual variation s of temperature and sal ini ty off the west coast ofNorway .
The method of representation has been devised by Mr. AKSELSTE R N .
The drawings have been made from investigations alreadypubli shed by HJOR T
In summer the l ayers in the surface water have been foundto be excessively warm
,but containing l ittl e salt , whil st the Atlanti c
water forces its way up from ben eath . Subsequently the high tem
perature descends , so that at a depth of 250 metres the greatestwarmth i s met with in December .
The per iodical changes thu s vary to a depth of 250 metres ,on the west coast of Norway . Up to the p resent time no iny estigations have been carri ed out during the whol e year off theseaboard of the Northern Ocean
,but there i s good ground for
believing'
that the conditions there are not very different to thoseon the west coast .
Th is form of brackets , w ith figures ins id e , ind icates the d ate of
l i terary publ ication s .
Mos s p . 91) reports observations of temperature fromLodingen , w hich show that at a depth of 100 fathoms the temperature does not vary throughout the year to
There are thu s along the enti re Norwegian seaboard of theNorth Sea and Northern Ocean , 3 deep region s of a very wel lmarked hydrographica l character , viz .,l . The Region of periodical changes, to a depth of 200 to
250 met res .T he Atlantic Region , to a depth of about 500 metre s .
2 . The Arctic Region .
Of these regions , i t i s ch iefly the uppermost that i s of i nterestto us
, as i t i s our main purpose to unravel all the condi tions whichmay influence the m igration of fishes . And it may well be presumed that the great changes p roduced by currents , by summerwarmth and w inte r cold , and the vari ations from year to year ofthe different factors , may be of the greatest importance to theperiodical fisheri es .
[O
In order to investigate these conditions , HJOR T , in 1895, made6 sections of the sea off the coast between Stavanger and Lofoten ,and through the assi stance of the authoriti es o f Bergens Museum ,
Noanc aann was enabl ed to go over the same s ection during thew i nter of 1896 .
The results of these investigation s are giv en on Pls. 6 and 7.
The sal inity i s represented in sim ilar tones to those used by HJOR Tin hi s former work
Water,the sal in ity of w hich exceeds
35 °loo i s denoted by dark blue col ouring .
34 to 35 l ight33 34 dark green32 33 l ight
l ess than 32 yellow
Thi s method of representation was founded by the Swedishhydrographers Pnrrnassox and EKMAN That thi s i s right i sshown by the fact that the l ine s of sal ini ty , in many instances ,represent the natural boundarie s between layers of different originand character ; each of such layers generally possess ing i ts owncharacteri sti c cond itions of temperature .
Thi s method of d ivi sion has been tested during several yearsinvestigations in the Skagerak , w here PETTER SSON and EKMAN separateand recogni se the fol lowing l ayers of water "
Atlantic Water, Sal ini ty 35 °/oo and upwards .
North Sea 34 to 35Bank 32 34
Baltic l ess than 32
On the Norwegian seaboard of the Northern Ocean,the waters
of the Gulf Stream can be di scerned from the coastal l ayers bythe 35 °
/oo l ine of sal in i ty . As will be s een from the tabl es,there
is often a great variation in temperature along thi s l in e . Butnaturally al l k inds of changes are to be met with
,and in many
instances i t would , possibly , have been more , or equal ly correct to
fix the boundary,for instance , at °
/oo. But, practi cally, thiswould make but l i ttl e d ifference , and therefore we deem i t preferable to use s ingl e l in es throughout , in order that the figures mayretain their value independent of theorie s and indiv idual opinions.
We regard i t as doubtful whether the coastal water can , inthe Northern Ocean
,be divided into such naturally confined l ayers
as i n the Skagerak,but thi s must be more accurately investigated .
On practi cal grounds we have retained th e curves and the sam ecolouring as for the Skagerak waters , but without intending therebyto indicate the variou s sources of the coastal waters .
For th e sake of brevity , we wil l in the fol l ow ing few wordsdenote these waters whose sal ine contents amount from 34 to 35as “
34 water” , and , in l ike manner, descri be the other degrees ofsal in ity .
The sections gi ven on Pls. 6 and 7, confi rm the correctnessof the re sul ts given on Pl . 5 , Figs . 3 and 4.
In summer the 35 water ri ses well up towards the surface,
being surmounted by coastal l ayers of various degrees of salin i ty .
On the Norwegi an west coast (Pl . 6 , 1 a and 2 a) there stil l remainsa quantity of water of l e ss sal in ity than 32 0
/oo, probably of Balticorigin . Furth er North
,coastal water i s met wi th , consisting almost
exclusively of 3 3 and 34 water . The temperature in the coastallayers decreases
,ev enly
,from the surface downwards
,but the A t
l an ti c water occasionally exhibits a ri se of temperature towards thebottom . The coastal l ayers are thus i n summer of l i ttl e thickness
,
but thei r salinity i s often somewhat low .
If we examin e the winter section s we find the condi tions eutirely altered . The l in e representing 35 °
/oo sal ini ty has on theshores of the Northern Ocean (Tabl e 6 , Figs . 3 b and 4 b, Table 7,Fig . l b) reti red to over 1 00 metr es of depth
,in parts to more
than 200 metres .On the shores of the Northern Ocean the 35 water wil l be
found somewhat nearer the surface (Pl . 6 , Figs . 1 b and 2 b) .Along the enti re coast at that season , there will be found a
thick layer of 34 water, and also of 33 water, which partly coverthe coastal bank s .
The temperature of the 34 water i s not much lower than thatof the Atlantic water
,generally from 5° to fall ing seldom to
but , on th e other hand , the temperature of th e 33 water maybe or l ess than that .
It i s necessary now to discover the origin of thes e thick layersof water
,and there are two theori es respecting that
,which may be
taken into consideration , v iz . , that they are either formed at thespot by a mixture of river an d Atlantic water
,or that they are
brought by curren ts from other parts .The Swedi sh hydrographers are of opinion that , a combination
of layers of water o f different Specific gravi ties does not occur , toany great extent
,excep t in shallow seas .
In that case the 34 water on the Norwegi an coast coul d onlyori ginate from places where a vast quantity of water
,of a sal in ity
of 34 to 35 exi sts. The Swedish hydrographers thereforeassume that the 34 water must proceed from the Arctic Oceani tsel f
,or the north western portion of the Atlantic Ocean . In
summer there i s not any connection between the Arctic Ocean andthe shores of No rthern Europa , but Ps rrs s sson and E li -MA N have
framed the hypothesi s that,in winter
,a current run s southwards
from the north - east coast of Iceland to the North Sea,or to the
Norwegian coast at Stadt.Thi s hypothesi s i s mainly based on the biol ogical conditions
,
for,in the Skagerak
,there will b e found amongst the Plankton
,
numerou s northern forms at the very time the 34 water attain sits greatest thickness (see A UBIVILL IUS CLEV'E
As we shall show in the following remarks , the distribution of
the Plankton organ isms may be equally wel l explained by othermeans
,but there are
,neverthel ess
,hydrographical facts which
appear to support the hypothesi s .Thus i t wil l b e seen from Monx
’
s Chart of Surface Temperatures i n the Northern Ocean , for March and August , that duringthe winter a wedge of cold water advances from the east coast ofIceland in a south- east directi on tow ards the Faroe i sl ands .
It has subsequently been shown by R Y DER [95] that a largeportion of the East Greenland Polar current turn s eastward
,run
n ing past the east coast of Iceland , in stead of flowing onwardsthrough Denmark Straits .
A bottl e thrown into the sea off the coast of Greenland in72° 58
' N . l at .,and 20° 36 '
W . l ong ,which was picked up after
the lap se of three years at the F arce i slands,l ikewi se supports the
assumed existence of such a south - flow ing Polar current .It i s a matter of fundamental importance in studying the distri
huti en of organ isms,and the migration of fishes on the Norwegian
banks , to know whether such a current , flowing directly across theGul f Stream
,exi sts or n ot . Consequently the Norwegian investi
gations of the past few years have been directed towards solv ingthis question .
The above mentioned hydrographical section of the Norwegi ancoastal waters , made by HJOR T and N ORDGA A RD in 1 895—96 , didnot lead to any deci siv e result
,as the steamers placed at their
d i sposal in the coast towns,were not large enough to proceed to
the boundarie s of the water layers of the coast . On the otherhand
,in March and Apri l 1 897, H JOR '
I‘ succeeded in obtaining a
description of the w hol e of the Northern Ocean through the courte syof the masters of sealing and whaling vessel s .
Mr. JOHANNES BUL L,a shipowner at Tonsberg
,al lowed deep
water investigations to be made during the voyage of the“Ant
a rctic from Utsire to Iceland i n the beginning of March,and al so
from another of hi s v essel s sail ing from Iceland to F inmarken inthe beginn ing of April .
In addition to the above,L . TUFTE, master of the steamer
“Westye Egeberg”
,and ship -master J . O . SIMONSEN , kindly col
lected surface samples of water, and noted the temperatures whensai l ing to the fishing grounds off Jan Mayen in 1 897, whil e shipmaster F ODEN did the same , and at the same peri od , on hi s coursefrom the Skagerak , south of the Shetlands and Faroe i slands to thesouth western shores of Iceland . T he North Sea was [simultaneously examined along the steamship routes from Stavanger to Shields ,Christianssaud to Shields , and Christianssaud to Antwerp .
Plate 3 , has been publ i shed on the basi s of these observ ations .The l i nes of temperature are given in red , and the steamship routesin black . The cross l ines on them denote stations . Wherever thes tations are mark ed on the chart by a small ci rcl e , deep -water
investigation s have b een carried out. See b esides the H ydrographical Tables B . III—IV .
Mr. F ODEN ’
s track has not b een marked down,as hi s report
only reached us after the tabl es and pl ates had been sent to theprinters .
For the sak e of comparison , we have publ i shed TORN OE S’ Summer Chart of the N orthern Ocean Expedition
,supplemented by the
resul ts of the Drache Expedition,and by MOH N ’
s Curves of Tem
perature for August pl . XXVII) which are denoted on thechart in red .
In comparing these,i t wil l b e seen at once that the water of
the Gulf Stream , characteri sed by a sal in ity of ov er 35 i s farl ess widely di stributed during the coldest period of the year thanduring summer ; whil e the Polar current, which in summer barelyreaches the south - western point of Iceland , during the course ofthe winter increases in thickness in two great wedges which extendto 6 1 ° and 63 ° N . l at .
The results der ived from deep - water investigation s on the l ineUtsire—Iceland
,wil l b e seen on Pl . 6
,Fig . 1 . Both wedges go
down to a considerabl e depth ; the western one b eing the narrower,but with the lower temperature of the two . The sal in ity of theeastern wedge at a depth of 200 metres i s °
/oo, and tem
perature at a depth of 300 metres (see Tables p . 1 1 .
temperature Thi s i s thu s,probably
,Atlanti c water which
has be come somewhat mixed by friction with the surface current.At that per iod of the year the curve indicates 35 sal inity, orthe pervading .temperature
- curve forNow comes the question . Can the eastern wedge at any time
of the year traverse the Gulf Stream either in the direction ofStadt
,as the Swedish scienti sts at first presumed , or southward
towards the Shetland Islands and on by the north “east coast ofEngland
,as i s deemed probabl e by PETTER SSON and EK MAN in their
l ast treatise In the l atter in stance , the current might continne in the coastal currents of the North Sea, as indi cated byFULTON and
'
convey the waters along the shores of the NorthSea and on
,past the north west coast of Jutland
,in to the Skagerak .
PETTER ssON and EKMAN find a support to thi s assumption inthe drift of a bottl e which was set afl oat by RY DER off the southcoast of Iceland
,which
,after the lapse of a year, was picked up
off Heligoland .
Our chart,however
,shows that the wedges of the Arctic current
are certainly stopped by the Gulf Stream in the month of March .
To the north of Scotland the water i s very salt, and the curveof temp erature for 7° run s p ast the Shetland Islands in a northeasterly direction towards Stadt.
In MOH N ’
s Chart of Temperatures for the Northern Ocean forMarch
,the 7° curve l i e s stil l more northerly than we found i t in
1 897; and , as wil l b e seen from the following, the spring of 1897
was unusually col d in the Northern Ocean .
The western wedge , which , in 63 ° N . l at. , has a surface tem
perature of is almost imperceptibl e in 61 ° N . l at. On Mr.FODEN ’S voyage from the Skagerak to Iceland , 3rd to 9th March
the temperature on his almost westerly course from 59° 53'
N . l at . , to 63 ° 8' N . l at . , and 19° 42
'
W . long ,was 7° and up
wards,whil e the sal in ity throughout was or more . The
only thing along thi s track which coul d be observed as indi catingthe presence of the western Pol ar wedge , was a sl ight decrease oftemperature. The 8° curve of temperature , between 1 7° and 19°
West long . ,runs almost up to the Icelandic coast , but at about
1 5° W . long . ,tu rn s to the southward , and i s only met with agai n
in 6° 20'
West long . , and 60° 20' N . lat .
The A rct ic currents are therefore d efinitely stopped in thesouth ; and this al so appears to be the case in the east. Theresu lts derived from the observations made on board the two seal ingvessel s on thei r voyage from Utsire to Jan Mayen , shew that , ofi
’
Stadt , the surface of the Gul f Stream i s over three degrees o flongitude in breadth . It i s narrowest in about 65° N . lat.
,where
a combination of the surface layers from the w est and east cannotbe regarded as entirelv excluded . In any case thi s might be dueto a hitherto unknown eastward- flow ing sid e branch of the Polarcurrent .
We do not , however , regard such a combination as l ikely ,and if such real ly takes place , i t i s of no material consequence .On the one hand , namely , great bodie s of water are to b e metwith to the northward , of high sal in ity , and on , the other hand , theNorwegian coastal layers of a l ike sal in ity as the Po lar current
(34—35 °/oo) possess a higher temperature than the Arctic wat e rs .
On the coast of Nordland,the 34 water i s of a warmth , through
out of 5° to even during winter , whil st the temperature of t h eArctic w ate rs decli nes rap idly a s they reti re from the Gul f Stream .
As i t now may be considered proved that , i n March , no branc hof the Polar current traverse s the Gul f Stream
,i t ‘ i s not prob abl e
that thi s can happen at any other season of the year. The obser
vations made by the Danish Meteorol ogical Institu tion (ROTHE , [96 ,shew that February and March are the coldest ' months o f th e
year between the Shetland Islands and Icel and , the Polar currenthaving had time th roughout the winter to gain in strength andthickness, whil st the Gul f Stream , probably from th e autumn til lthen , has evenly d imin i shed .
According to the accounts of the Swedish sci entists,the Gul f
Stream ought to be penetrated in December,but during
,that
month, a pretty high temperature sti l l p revai l s i n the sea withinthat area.
Wh at then becomes of the cold bodie s of water which movein a SSE direction towards the North Sea ?
As we have seen that the Arctic water wedge,w est of the
Faroe Isl ands , i s undoubtedly absorbed by the warm Atl antic water ,i t i s probabl e that the eastern branch meets wi th a similar fate .It must become mixed w i th the north eastern offshoot o f the Gul fStream by which its (the Gul f Stream
’s) temperature and sal ini tyi s lowered . T hereby i t i s , indirectly , of great consequence , but theGul f Stream i s , however , so paramount, that the mixed current sare of a well defined Atlantic n ature
,with a sal i n ity exceed ing
35 °/oo, and a temperature above The body of water then
moves on , partly in a north easterly directi on towards the Norwegiancoast, and , partly , to the southward into the North Sea . This wil l
explain the drift of a na’s bottl e from Icel and to Heligol an d
wi thout i ts having been necessary for Pol ar water, wi th its Arcticconditions to flow across the North Sea .
By this means; too, Arctic organi sms may wel l enter the NorthSea and Skagerak
,conveyed by the Atl antic water which at that
time of the year i s of a temperature o f 5° to High Arcti canimal s , such as Clione l imacina woul d not be k i l l ed by suchwarmth , as that i s not greater than the Summer temperature inmany parts o f the Pol ar current (see Pl . It i s even probabl ethat the r i se of temperature would be favoura bl e , as the Arcti cwaters are , in winter, exeed ingly desti tute o f organic l ife .
Nei ther i s i t impossibl e that such sen sitiv e organi sms as theArcti c diatoms (Thalassiotlzrix, Cosci-nodiscus) are , in the combination , transferred to the Atlantic waters , but thi s supposition i s n otnecessary as they are n everthel ess met with in smal l m embers inmost ocean i c l ayers
,as wil l b e more clearly shown in our n ext
chapter .The hydrographic resul ts hitherto attain ed
,give thus
,i n our
Opinion , no ground for assuming that the Polar current at anyperiod of the year traverse s the Gul f Stream itsel f
,even by mean s
of a thin superfici al layer .PETTER SSON and Exams al so acknowledge p . 30) that
“In any case , the hydrographi ca l grounds for thi s assumption cannot be deci sive , unl e ss other facts in support of th e hypothesis befound in the resul ts o f th e biol ogical i nvestigations ” .
The biological conclusion s are,however, l ess tenabl e than the
hydrographical,as we shall subsequently shew . The cold layers of
water met with on the coasts of Norway during winter must,there
fore,originate in some other manner .A glance at the Summer Surface Chart of the Northern Ocean
Exp ed i tion (Pl . and our Win ter Chart (Pl . 3) will apparentlyconvin ce one that the changes in Norwegian coastal waters canonly ari se from two factors , viz . , the Atlantic water on the onepart ; the contin ent and atmosphere , the water from rivers , th ewarmth of the sun in summer and the col d of the winter on th eother . I s i t , however, poss ibl e by the aid of these factors toexplain the changes which , as above indicated , are p roduced bythe season s in th e Ocean , and in the di stribution of organi sm s ?
If on e studies Pl . 7, Fig . 1 a , which represents the conditionsof the West Fj ord , Lofoten , early in the summer , on e wil l perceivethat the sal i n ity then i s very great in the surface w ater of theWest Fj ord
,and that only in towards the fj ord s (Sal ten Fj ord)
are great bodie s of water met with of lower sal in i ty . H Joa 'r
’
s
investigations during the summer and autumn 1 895, shew that thebulk of thes e numerou s fresher l ayers increased greatly during thesummer and autumn ; see , for in stance the section from Hero inAugust
,Pl . 7
,Fig . 6 . The chief changes in the distribution of
sal in ity and temperature in deep water,occur during the month
of September. We append here two tabl es of observations on thesal in ity and temperature at v arious depth s off the Nordland coastone for July, the other for September .
In compar ing these two tabl es i t wil l be seen that1 . The 35 curve which , in July , was 50 m . below the surfacemust b e sought for in September at depths exceeding 1 20 m. ,
the curve was , i n July , at a depth of 20 m .
,but in
September was found at a depth of 1 20 m .
2 . The Surface Sal in ity decreased from to3 . The Surface Temp erature sank from 1 1 ° i n July , to inSeptember
,but, as a set off
,the temperature down in the
deep rose considerably ; for in stance from at a dep th of80 m .
,to
These condition s remind one greatly of those which havebeen shewn to exist on P] . 5
,Figs . 3 and 4 , in respect to the west
coast . The cond itions on the bank s in the North are,however
,
sti l l more in structive,becau se i t mu st be presumed that the tran s
placement of the temperature,downwards
,i s there not so dependent
on currents as on the west coast where the Bal tic current p lays agreat part . It was
,moreover , ve ry instructive to find that the
fre sh water played a greater and greater part the further a fj ordwas entered .
It thus shews that in the North,simultaneously with the
increased thicknes s of the fresh layers,a period
'
of heavy rainAs the accompanying table s shew , the rainfall increases
greatly in September,and from that month
,throughout the entire
sets in .
autumn until January or Feb ruary , a l engthy season of rain occurs .It i s an interesting fact that
,j ust at that time
,the fresh layers
increase in thickness , and that i t i s i n the fj ords , where the rainfal l through the agency of the rivers i s most p erceptibl e, that thel ayers chiefly increase . One factor, which al so must be regardedas of great weight in respect to these conditions , i s the influenceof the winds .
If,in accordance with the annual reports of the Meteorolog ical
Insti tute,one draws curves representing the frequency of the various
winds dur ing the vari ou s months of the year,i t w il l be seen (as i s
al so shewn in Capt . R UN G ’
s atlas of the barometrical pressure overthe Northern Ocean) that, during summer , westerly winds are themost preval ent al ong the whole of the north west coast of Norway.
These must,during the summer
,contribute to force the Atlantic
waters in towards the land . On th e other hand,during the ant
umn and winter th e direction of the wind is , to qui te a paramountextent
,south easterly
,interrupted , however, occasionally , by westerly
gal es . The south easterly winds thus drive the water out of the
fiords to the banks , and the gal es must, on the whole , mix up thebodies of water
,and that to a great depth .
That such a m ixture must take place to a very great extenti s cl ear , i t appears to us , from the sal in ity becoming steadily l essas the autumn advances . The homogeneousness is greatest inJanuary and February , as both the atmosphere and the fre sh waterfrom the rivers cool , especially , the upper l ayers .
1 2 3 6 5 6 7 8 9 10 11 12 1 1 2 3 4 5 6 7 8 9 10 11 11 1
ZkOW ‘W 9 5 0 3 o o o o o Q
2 0 0
1 80
1 6 0
1 40
1 2 0
8o
sw am , JIM ;
R ainfal l in m i ll imetres,during the various mon ths of the year, at
Svolvaer and Floro’ .F ig. 1 .
metres
It is known that layers of water of different sp ecific gravitiesare not at al l incl ined to combine . Thus the Baltic current,during the summer
,floats upon the salter layers beneath
,without
its being possible to observ e any admixture .These conditi ons do n ot
,at al l events , exi st in the North
during the autumn,or in western Norway . Thi s i s seen
,for ih
stance,when the den sity of the water during the winter at various
depths i s calcul ated . The density of the Ocean water during thevarious months of the year may be calculated from Figs . 5 and 6 .
If one takes an example from February , one obtains thefol lowing figures
If i t be remembered that the l imi t for the accuracy of the
method of investigation may be set at 1 in the fourth decimal , i tw il l be seen that there has been an almost homogeneous l ayer , i nrespec t to density , from the su rface to the bottom . Under suchcircumstances the power of the wind , as w ell as that of cold above ,must play a great part. Cool ing from above would natural ly up se tthe balance , as the upper particl e s would become heavier an d consequently sink down through the lower and light l ayers . Accordingto Mons , the cool ing of sea water from 6° to 5° woul d thus iacrease the specific gravity by from 6° to 4° by and from
6° to 3° by in the fourth decimal . A cool ing of the surfacelayers bv 3° woul d thus , from the above exampl e , cause them tosink to a depth of 200 in .
Even the distribution of temperature shews , moreover , that avertical ci rculation must take place . Warmth spreads very slowlythrough water when its diffusion i s not encouraged by ci rculatingcurrents . The vertical circulation may be checked when the sal in i tyat the surface i s much l ess than at the bottom , thi s causing agreat d ifference in its specific gravi ty . Thus , in the upper part ofthe Christian ia Fjord
,in September 1 897
,the temperature
,at a
depth of 60 metres , was but whil st the surface tempe rature was13 to On the west coast where the cont inenta l warmth i sless
,the temperature at a s imilar depth was , in Sep tember about
1 2° (see Pl . 5 , Fig . There the vertical circul ation must , therefore hav e been very considerabl e , much greater indeed than in theChri stiania F jord .
MUR RAY [88] reports some interesting example s of th e powerof the wind . A Scotch freshwater loch was examined before andafter a gal e . “
I
hilst the i sotherms prior to the storm were al lparal l el wi th the surface (a proof of the qui et state of the lake) i twas observed
,shortly after the gal e
,that a great portion
-
of thewarm water had been blown to one end of the l ake .
As wil l b e seen from the foll owing outline , al l the i sothermsafter the gal e run towards the bottom in the di rection the wind .
F ig. 2 . Section of a Scotch lake after a gale , in the d irect ion ind icated by
the arrow. F rom a mm; of Mommy ’s Treatise in the Scotch Geographical
Magaz ine 1888 by VON Bonn .
MUR RAY has also shewn , from other observations,th at gal es
can even force th e warm water beneath the cold,and i n such a
case a mixture takes place . The Norwegian coastal w aters are,
during winter,j u st as homogenious i n rega rd to specific gravity
as those of a lak e where, in summer , variou s degrees o f temperature are met with at vari ou s depths ; and w hen i t i s rememberedthat the sea wil l break Off the west coast of Norway in 20 fathomsof water
,i t wil l be perceiv ed that al so there a great m ixture must
take place .I f
,however
,i t proves to be the case that the formation of
th e various l ayers of water tak es place i n the manner previou slyindicated from mere local cau ses
,great fluctuatio n s can
,neverthel ess ,
according to one Opini on , take place in the bodies of water . TheScandinavian coastal w aters
,from the Scaw to F inmarken ,
must beregarded a s one hydrographical system which certainly i s , mainly ,in motion northwards along the shores of Norway
,but whi ch by
the force of w ind may be turned in variou s direction s . I t i s e specially interesting to know from the Swedi sh i nvestigations , that greatchanges can tak e place i n the Swed ish fjords , as at one moment afj ord may be fi ll ed with fresh Bal tic Water
,whil e at another th e
sal ter water,the so cal l ed “Bank Water ”
,of a sal ini ty o f 32 to
30 can force i ts way in . It thus proves,w hat the Swedish
Scienti sts have indicated , that where great d ifferences exi st in thespecific gravi ty of the layers
,they remain l ik e two very different
seas who do not associate the one with the other . The summercondition s are v ery instructive . In the Chri stian ia Fjord , for ihstance
,the cold water of the prev ious winter will b e found along
the bottom,whil e the warm fresher l ayers appear on th e su rface .
Even if the amalgamation s thus play a ‘great part,i t i s , how
ev er,seen that they do not Occur rapidly , and that layers , once
formed,can often exi st for long periods of the year
,without being
much affected by the influence of the super - jacent waters . In thecourse of a long time
,months for i n stance
,the great differences
may , success ively , be overcome , and two layers become amalgamatedto one .
We have thus come to the convi ction that the changes in theNorwegian coastal waters are dependent , mainly , on the Gulf Streamon the on e hand , and , on the other , on local causes . The Polarcurrent has no direct influence ; but our inv estigations prov e thati t i s o f a thickness
,which
,indirectly
,must have th e greatest in
fluence on the enti re current- system of the North Atlantic , andthe climate of North ern Europe . And i ts importance i s stil l furtherin creased through the period ical variation s in its thickness anddistribution .
Whil st the ‘Polar current wi thdraws during the Summer tothe north eastern coast of Icel and , and the Gulf Stream fi l l sthe whol e of the central portion of the Northern Ocean , the Polarcurrent increases in thickness during the winter , the Gul f Streamretire s
,and its waters become partly bl ended with water from
th e coast.NANSEN l ikewis e reports [97] that , during the winter , the flow
of the surface waters of the Arctic Ocean was in the directi on o fthe Northern Ocean and the Atlantic
,whil st the currents during the
Summer are varying,in part
,the reverse o f those of the winter .
Stil l more interesting than the annual periodical fluctuations ofthe Pol ar current , i s th e fact that, from our observations, i t varie si n i ts devel opment in d ifferent years .
On Pl . 4, will be seen two hydrographical sections made inthe middl e of May 1 896 and 1897, on board the crui ser
“Heimdal ” .
Both were made on the same l ine from about 6 1 ° N . lat . , 4° E .
long . ,to 67° N . lat .
,8° W . l ong . The difference between the two
i s p erceptibl e . In 1 896 , the Gul f Stream was twice as broad onthe surface as in 1897
,and
,i n the deep , i t i s met with on great
areas beneath the shall ow Polar current at a depth of 1 00 to 1 50metres . In 1 897, on the other hand , the Polar current i s at l east200 metres in depth , down as far as 64° N . l at .
,on the meridi an
of Greenwich . The consequence Of th is was , that the temperaturethroughout
,was 2 ° lower i n 1 897 than in 1 896 .
Compari sons shew that the cond ititions can vary greatly atl ike seasons in different years . The cause of thi s may be dueto the derangement of the season s
,or al so to the Gulf Stream
and Polar current not having a l ike development in different years .Several points favour the l atter hypothesi s . If one lays down
the track of the “Heimdal in May 1 897, on the chart for Marchof that year
,i t wi l l be seen that the boundary of the Polar cur
rent ou that line i s pretty wel l unchanged between March and May .
On the other hand,it may happen in certain years that the surface
temperature in March,can be so di stributed that the Heimdal l ine
could be marked down to represent it .Professor MOHN has been so kind as to allow us to make u se
of the original observations from which be constructed his Chart ofTemperature for March . It appears that in som e years
,for instance
1867, that the 5° curve of temperature , which may be looked uponas the boundary of the Atl antic wate r, makes a great turn towardsthe northwest , in the d irection of Jan Mayen , up to 63 ° N . l at .
,
5° W. long .
,and that the 8° curve can pass many mile s to the
north east of the Shetlands (for in stance in 1867,
It thus appears as i f the Polar current were differently developed in different winters
,and in 1897, i t seems to have been of
an unusually great thickness . This i s al so confirmed by comparingthe curves of temperature on PI. 3 , with MOH N
’
s Chart of Temperature for March [87, pl . XXVIII] , which was constructed on theaverage temperature from the observations of 1 9 years ( 1 867
In the southern portion of the Northern Ocean the curves
(especial ly those for 4° and in 1 897, are further towardsthe south and east than in average years , but as a counterbalanceto this
,unusually high temperatures wil l be found along the south
co as t of Iceland .
The ice - conditions too,can
,according to a na
’s investigationsvary greatly from one year to the
As will be seen from the Danish Ice Charts , the boundary ofthe ice remains somewhat unchanged throughout the months ofMarch
,April and May . RYD ER l ikewi se s tates [96 , p . 24]
“Theboundary of the ice
,under the influence of prevail ing winds may
change,somewhat
,backwards and forwards , but , in the main , retains
R YD ER See also the R eports of the Dan ish Meteorological Inst itute on the Ice - condi tion s in the waters eas t of Green land and in Davi s S trai ts[ 1893
i ts position unti l the end of May . On the other hand,in Jun e
,
the boundary of the ice commences to retire in a westerly d irection with a growing speed
,which increases v ery considerably in
July and August. ”
We have above shewn that al so the distribution of the layersprobably remains somewhat unaltered from March to May .
If new a compari son i s made between the spread of the ice,
and the conditions of the current in the spr ing of the two years1 896 and 1897, i t wil l be seen that there was more ice to thenorth and east of Iceland in 1 896 than in 1 897. which was anunusually open (ice- free) year . In 1883
,when the condi tions o f
the current were somewhat similar to those of 1 896 , there waslikewise much ice .
From the re sults already obtained,i t thus appears that the
Polar current,east of Iceland
,i s strongest in those years when
th ere i s l east ice in those parts . But i t must be l eft to futureinvestigation s to di scover the regular connecti on between thosephenomena .
In thei r latest report PETTER SSON and EKMAN give anaccount of some observations on the distribution of the Gulf Stream
,
between Spi tzbergen and Norway,during the summers of 1896 and
1 897. They have di scovered that th e Gulf Stream ,in those parts
,
was unusual ly thick in 1897 ; whil e in 1 896 i t did not extend sofar , but , nevertheless , sti l l further than noted in the observations ofthe Northern Ocean Expedi ti on dur ing 1 876—78 .
Whi l st thus,in 1897, the Atlantic water , between Iceland and
Norway,had withdrawn unusually far back until the first half of
May,in the latter days of the same month i t was of unusual
thickness betw een Norway and Spi tzbergen .
These facts are,however
,sti ll too i solated to al low of ou r
com ing to any definite conclusions from them . The conditionsare complicated
,and systematic investigations must be made at
al l seasons for many years , if any compl ete knowl edge of thesystem of currents i s to be gained .
The observati ons that have already been carri ed out but shewthe hydrographical vari ations in the Northern Ocean to be so
great , that they may be presumed to have an important influenceon the changes which both the migration of ‘ the fishes
,and the
meteorological conditions prove to exi st from one year to another .The connection between the hydrographical condi tion s and themeteorol ogical
,has already been indicated by O . PETTER SSON
and still further reported on by ME IN H A RD USBy means of the International co- operation now being carri ed
on,the question w ill undoubtedly be solved , though crav ing much
labour,and i t can hardly be exp ected that any great results wil l
he arr ived at until the investigators have a sea- going steamer attheir di sposal throughout the entire year . Up to the present theyhave been dependent on the goodwill of private i ndividual s , andobservations in the open sea have only been carri ed out , whenopportun ity offered
,during tho se seasons of the year in which the
sealing vessel s sai l to the Arcti c Ocean .
H. Plankton Studies.
(Ia hyd rographical studie s of temperature , sal ini ty , the flowof currents &c . 650 . canno t of themselves giv e such an insight
in to the system of ocean currents and climate , as can be gainedby simul taneously investigating the development and distribution oforgani sms
,and endeavouring to find out the connec ti on between
the hydrographical and biological rel ation s .
[ t has already been shown , from numerou s observations , thatthe hydrographical conditions are of the greatest importance onMarine Organi sms . This i s best known in respect to those of thebottom ; and Pars nsns
’
s work in the Cattegat and Loas nz ’
s
deta i led monograph on the Bay of Q uarnero have contributedimportant addi tions to the enl ightenment of the bottom organi sms ’
dependence on the hydrographical conditions .The study of the Pl ankton Organisms
,has only been taken
up of late years ; and it i s mainly the Swedi sh biologists CLEVEand A UBW ILL IUS , who together wi th the hyd rographers PETTER SSONand Exams , have sought for the connection between the periodsof the Plankton ’ s appearance
,and the hydrographical variation s .
The above named sci enti sts are of the Opini on that the variou socean territori es are characteri sed by special organi sms whichaccompany the w aters in their flow . Therefore
,they assume that
,
the origin of a current can be dete rmined by investigating i tsPlankton .
In order to determine the value of such a conclusi on,one must
be ful ly conversant wi th the d istribution and condi tions of l i fe ofsuch organisms , and , therefore , before we enter more minutely intothe results arri ved at by the Swedish scien ti sts
,we wil l give a
revi ew of the biol ogy of the Plankton Organisms , and especial lythat of the Pelagi c Diatoms .
Like as i s done by HACKEL we div id e the PlanktonOrgani sms i nto Oceanic and Neri ti c groups . The O c e a n i c formsinhabi t the open sea , are e n t i r e l y i n d e p e n d e n t o f t h e bott o m , and can go on propagating in thei r fl oating condi tion withoutundergo ing any regular phase of development . They can be driv enin to the coast by ocean currents
,and many can continue to pro
pagate there provided the cond itions are favourabl e,in such a case
becoming mixed with the Neri ti c forms .The N e r i t i c Pl ankton Organisms are in some manner or o ther
dependent on the bottom ; and this , in respect to the various species ,
can be condi tion al on very d ivers e causes . Thus there wil l befound in the Neritic Plankton a quantity of larva forms of animals ,which in a matured state belong to the faun a of the bottom andthe coasts (for instance fish
,echinoderms
,annel ids) . Some others ,
such as the medusse,undergo establi shed phases of youth, whil st the
matured ind ividual s belong to the Plankton .
Other Neriti c Organisms can certainly l iv e and increase nubind ered in a floating state
,but experi ence teaches u s that they , never
theless,keep exclus ively to the shall ow waters of the coast. They
must,therefore
,for some reason or other
,be dependent on the bot
tom,and i ts influence on the wa ters . Thi s esp ecial ly affects the
lower organi sms of the Plankton,the Pelagic Algae, which con sti tute
the primitiv e nouri shment to be met wi th in the ocean , and mostof these are to be found mainly along the coast .
In the North Atl antic,the Vegetabl e Plankton consi sts almost
enti rely of D i a t o m s and P e r id in s .
Both these group s of pl ants consi st of on e - cell ed organisms ,which
,occasional ly
,may be uni ted in a chai n - l ike col ony , in which ,
however,each l ink possesses entire independence .
Propagation occurs by a parting,or div iding of the floating
indi vidual s,and continu es excessi vely rapidly so long as the outer
condi ti on s of l ife are favourabl e to the Speci es concerned .
But,under certain ci rcumstances
,which a s yet are bu t l i ttl e
known in respect to the indi vidual speci es,the partition of the
cell s ceases , and in the Neri tic forms thick wal led Cysts or RestingSpores are fo rmed which fal l to the bottom .
The Cysts are best known from the Pelagic D i atoms,which we
therefore describe at greater length .
The Cell s o f the Pelagic D i atoms are for the most part verythin wal led , the protoplasm forming a thin sack within the wal l s ,whil st the greater portion of the i nterior of the cel l consi sts of alarge sap vacuole . On account of thi s con struction the capacity ofthe cell i s very great in compari son to i ts sol id substance
,while
the sp ecifi c gravi ty i s rela tively l i ttl e,but l i ttl e greater than that
of the sea water .In consequence of thi s the alga sinks but v ery slowly to
the bottom , even if i t does not by i ts own powers , viz .
,by the
formation o f gas , keep afloat . Moreover,the surface i s often
covered with hol l ow hairv growths (as in Chwtoceros) , or fine sl imy
threads proceed from hol low Spines (as in Thalassiosimfl , whichcontribute to the alga ’s powers of flotation .
At the same time that these pecul iari tie s in the constructionof the alga are favourabl e to it
,i n i ts floating state , so long
as the condition s of l i fe are propitious,they weaken its powers of
resi stance to vari ations in the physical and chemical condition ofthe ocean . In the Open sea the changes are slight , and take place
gradually ; but , near t h e c o a s t , much fresh water combines wi ththe sea water
,and the temperature var i e s much more there with
th e season s than in the open sea in corresponding latitudes .As a protection against such vari ations
,the Neri tic Diatoms
are given their Spores , which are formed towards the close of the
peri od of vegetation .
The protoplasms of the cel l s wi thdraw from the hairs (in Cheetoceros) , and away from the wal l s of the cell , first on one side
,
where a new,thicker
,arched valv e forms inside th e old one
,thus
dividing the original cel l into two spaces , of which only one contain s the protoplasm . Subsequently , the protoplasm wi thdraws fromthe other side of the original cel l , and becomes enshrouded in athick
,strong sil i ciou s shel l . The spore i s than fully form ed
,but
remain s enclosed within the wall s of the original cell until that fall soff or dissolves . The substance of the cel l has now become reducedto half or quarte r of its former capacity
,and the wal l s are about
th ree times as thick a s the vegetal cell wal ls . The wall s mayoften be furnished with spin es or other appendages
,bu t these
spines are sol id,not holl ow l ike the hai rs of the vegetal cel ls .
In the different famili es and Species,the method of formation
of the spores vari e s somewhat in the detai l s,but in most of them it
takes place in the manner above described . and has already beenaccurately defined by Sonurr [88] i n re spect to some Neritic Chastoceros species from the Bay of Kiel .
As soon as a speci es commences to form spores i t graduallydi sappears from the Plankton , the spores sinking to
'
the bottom asind icated by SentiT'
r They possess a much greater power ofresistance than the vegetal cel l s
,as the diffusion takes place l e ss
rapidly through the thick cel l wall s . Thus,for in stance
,they are
much more sl owly di scoloured by al cohol than the vegetal cell s .The spores have been known from the earl i est period of dia
tomic research . The diatoms have been mostly sought for in samplesfrom the bottom
,in which the vegetal cell - wall s of the Pelagi c forms
are very seldom met with , whilst the spores are found somewhatfrequently .
Owing to this i t i s that EHR ENBERG [45] has figured severalfo rms of spores . without however knowing their true character .The first speci es of the Chwtoceros was but described from thespores
,whil st the accompanying vegetal cell s were only di s
covered many years afterwards (Chwtoceros didymum , Ch. fur
Spores‘
within the vegetal cell s,the so- call ed i n n e r c e l l s
,
were first described by BR IGHTWE LL [56] in the Cheetoccros Wighami,subsequently by LAUDER [64] i n some Species of Chwtoceros obtainedfrom Hong Kong
,and in th e Bacteriastrum carians later by CASTR A
A d etailed accoun t of the organ ic structure and various floating ap
pliances of the Plank ton D iatom s is given by SCH UTT A ccord ing to new , and s til l unpubl i shed observat ion s by GR A N .
CANE GR UNOW and by others . It was first SCHUTT whosubjected them to a detail ed inve stigati on .
By the efforts of CLEVE [94 , 96 , 1—2,97] and GR AN [97,
1—2] sp ores have been shown to exist in most of the Neriti cDiatoms found on our shores
,and these are al so being discovered
in speci es in which they were formerly unknown . We thereforeconsider i t l ikely that in the course of time they wil l be found inal l Neri ti c forms .
Up to the present they are known to exist in the following28 speci es of the Norwegian coasts .
Bacteriastrum varians
Biddulphia aurita
mobiliensis
Chw toceros cinctum
constrictum
contortum
coronatum
curvisetum
debile
d iadema
didymum
fm‘
cellatum
gracile
laciniosum
rad ians
Schuettu
scolopendm*
)scimeanthum
simile
sociale
teres
Weissflogu
Wighami
F ragi laria ocean ica
Melosim
R hiz osolenia setigem
Thalassiosim gravida,
hyal inaN ordenskidldu
The Norwegian Neriti c Diatoms in which the spores are notyet known
,consi st of the following only
,apart from the true rarities
Ce mtaulina Bergo'nii L audem
'
a annulata
Chwtoceros crinitum Lep tocylindrus danicus
Willei Podosim glacialis
Coscinod iscus polychw dus Skeletonema costatum
Ditylum Brightw elli T halassiosim gelatinosa
Eucampia Z oodiacus Coscinodiscus exentricus v.
Guinardia flaccida gelatinosa) .
Most of these are rare sp ecies , we having met with but threein any great number (Guinardia flaccida, L ep tocylindm s danieus,
Skeletonema costatum) . It may,however
,occasionially be difficul t
to determine whether a speci es i s oceanic or neri ti c , especially if
i t only rarely appears . and then in small numbers . It i s , therefore ,not improbabl e that some of the l atte r Speci e s which have beendenote d above , wil l . on further investigation s being made , proveto be oceanic (for instance Gui
-
nard ia) .
The spores are al so known to exi st in a number of fre shw ater forms . In the Plankton Diatoms of lakes , they have only
been known of later yea rs (Laurs nnomv B . SCH RoD s s
as the se algze themsel ves were only d iscovered a few years ago .
But in bottom - forms . and especially in those specie s which in
habit ponds and pool s,they have long been known and Spoken
of under various names such a s,i n n e r c e l l s , g e m m ae C r a t i
c u l a r- Z u s tii u d e"
; see Prrrz sa Other freshwater algaehave al so simil ar cysts as the diatoms .
In the fre shwater forms they appear , especial ly when the pondsd ry up . The algae, by thei r a id , repose in the dry mud until th eyagai n obtain favourabl e cond itions for thei r development . Thi spower of re sting . w hi ch i s a necessary condition for popul ating thepools wi th l ife
,i s al so met. wi th in animal s of vari ous kinds ; cru
staceaa. rotatories , and other dwel lers o f the ponds can , l ik e thealgae, form encysted resting stad ia .
In these o rgani sms the spores chi efly serv e the purpose ofpreventing them from drying up . The outer cond ition s whichl ead to the formati on of spores in the Marin e Plankton are stil lunknown . Neither does one as yet know anything concerning thei rsprouting
,or the cond iti ons under which such takes pl ace .
The physical and chemi cal factors whi ch , i t may be presumed ,are of importance to the l i fe of the algae , are light, warmth , andthe chemical constitution of the sea water . All these factors varymost in the upper l aye rs of wate r , whil st the condition s as a rul ebecome more uniform the deeper one descends .
If now the Spore s , as we presume , are. of any con sequence toth e continued exi stence of the species then the diatoms must benot only dependent on the hydrographical condi t i on s of the surfacelayers in which they vegetate
,but the hydrographical condi tions at
the bottom must al so be of such a natu re that the Spores mayperi odical ly re st , or be roused in to sprou ting . If a rich N eriti cFlora i s to have a chance of developing i tsel f, and he annual lyrenewed from spores at the bottom the latter mu st not l ie beyondsuch a d epth as to allow of the yearly variati on s in l ight , tem
perature &c . reaching i t.Our deep Norwegian fjords , w hi ch are constantly dark at the
bottom , and where the bottom - temperature throughout the year canonly vary from 1 ° to 2° degrees
,canno t be expected to contain
any stat ionary Nerit ic Plank ton . On the other hand,i n shallow
fiords or coastal waters , the l ight can penetrate , and the annualperiods of temperatu re can be percei ved
,more or l ess perceptibly
,
down to the bottom itself. There during summer a ri ch floraof southe rn forms can be rou sed to l i fe
,which rest during the
winter whil st. on the other hand , during that season , the northernSpecies can meet with so l ow a temperature as to al low of thei rgrowing up .
From thi s poin t of v iew we will compare the Neri ti c Flora ofthe various northern coastal waters , which hi therto has been bestknow n , and endeavour to shew that the true cond itions corre spondexactly to our assumption of the importance of the bottom .
The typical specimen of a shal low fj ord is L i m Fj o r d , whoseremarkabl e p lank ton - conditions have been described by Dr . C. G .
JOB . PETER SEN i n hi s lately publ i shed workThe depth of the fj ord averages 3 to 4 fathoms , and the hy
drographical condi tion s may be regarded as unique from the su rface to the bottom .
The temperatu re may vary from to Cel siu s . A o
cording to PETER SEN ’S investigation s , the Plankton i s excess ivelyabundant for most part of the year
,and notwi thstanding that the
water in the Lim Fjord i s in constant movement from the NorthSea to the Cattegat, i t n ev erthel ess po ssesses a Plankton Flora ,which both in qual i ty and quantity i s sharply defined from thatof the North Sea
,and which i s
,in the main
,d ifierent from that
of the Cattegat .The Lim Fj ord al so posse sses a l ocal
,stationary D iatom -Plank
ton which changes in composi tion with the season s,but which proves
to be quite different from the Plank ton in the neighbouring seas atall times of the year
,as i s proved by PETER SEN who carried out
three s eries of continuou s observation s throughou t the Lim Fjordfrom the North Sea to the Cattegat (October 96 , Apri l and July
The variou s species succeed each other with the seasons . InDecember and January
,the Plankton i s v ery scarce ; in February
and especial ly in March , the win ter forms (Biddulphia aurita,Lauderia, cystifera) appear ; in Apri l thes e are succeeded by thespring forms , which in that month bring the amount of Planktonto a maximum . In May and Jun e
,the Plankton is somewhat less
,
but during the summer months o f July—September the fjord wasagain fi lled wi th great quanti ti es of di atoms
,especially Chaetoceros debile .
All those speci es which characteri s e the Lim Fjord Planktonare Neritic fo rms which produce Spores . PETER SEN concludes thatrich Diatomic Plankton must originate in the Limfjord i tself fromthe interaction o f the bottom and the waters that fl ow in to thefj ord . Of what thi s i nteraction consi sts he cannot express anydecided Opini on .
It app ears to be hi s id ea that the great developmen t of thePlankton Flora in the Lim Fj ord i s due to the exceptional ly fayenrable cond iti ons that are present there
,as a greater amount of
ni trogenous compounds are conveyed to i ts waters than i s to bemet with in the Open sea , or d eep fj ords .
This i dea,which in connecti on w i th other matte rs
,was first
promulgated by HENSEN , and subsequently by STBODTMA NNhas been adopted in resp ect to the Plankton in l akes , seems to bewel l founded , when i t i s remembered that the open sea i s highlydefi ci en t in ni trogenou s compounds .
In the mud of shal low fjords a great mass of organ ic substances are always present
,which
,gradually rotting
,giv e off nitro
gen to the water .Thi s factor
,however
,only becomes of consequence provided
germs are present whi ch can uti l i se the favourabl e cond itions ofnouri shment. One may imagine that the diatoms enter the fjordfrom without , and the oceanic species , which especially in May andJune appear in quantitie s , are probably introduced by the in - flow ing
curr nts .But the Plankton of the Lim Fjord chiefly consi sts of Neritic
forms , and as the Neritic Flora of the fj ord i s different from that
Plankton . As already mentioned the bottom temperature throughout the v ear remains at 5° to 7° degrees .
On account. of the ci rculation in the upper l avers of waterof the Skagerak and Cattegat , the chi ef thing to be determinedis the extent to w hich the indiv idual parts of the coast in thetwo seas contribute to the j o int stock of Plankton . Probablyall the surrounding shores a re centres of development of Neriti c forms .
T he ci rculation makes the condition s of l i fe so uni form that ,in al l probabi l i ty , those species which are almost al ike sink to thebottom with thei r spores
,and from these spring to l ife again al ong
the enti re coast, just as, for instance the fixed algte
- tlora i s somewhat uniform on all the shores of the Skagerak . The ci rculationfavours al so the Neriti c forms , as i t conveys the warmth of summerand the cold o f winter along the coasts dow n to a considerabl edepth . so that the range of temperature may be extraordinarilygreat . Thus
,for in stance
,in October 1897, there w ere warm layers
of water crowded up i n the north eastern porti on of the Skagerak
,of such a depth that the temperature (at Langesund) was 1 2°
down to a depth of 250 metres .The Neritic Plankton of the N o r t h S e a does not appear to
be nearly so pl ent i ful in ind ividual forms as the Skagerak .
Thi s is shewn up ch iefly by PETER SEN ’
S inv estigation s [98Table I] .ton than the Lim Fj ord and Cattegat , but the sp ecies met wi th in
Of Neri ti c forms i t i s real ly only
The North Sea proves to be not only l ess ful l o f Pl ank
i t are,paramountly , ocean ic .
Biddulphia nwbilie nsis , which occurs in any nameworthy quan ti ty .
CLEVE S Tables for th e North Sea [97, Tabl es VI VIII,IX]
al so indicate a majority of oceanic forms . The German Exp edi tionto the North Sea, found l esser quanti ti e s of perid ins and diatomsthan in the Bal tic and Gulf Stream [se e Scnurr whil st G .
MURR AY [97] found great quanti ti es of Ner iti c diatoms dur ing th espring along the North Sea seaboard of England , especial ly Skele
Ou the North Sea seaboard of Norway , fromThe
resul ts of our investigation s there wil l be found in Tabl e 1 station1—6 ; Table 3 , St. 73—76 , and Table 5 , St . 179—185 . The Station s 1—3 and 1 79—183 are off Stavanger ; 4—6 and 183—185
off Marsten Lighthouse n ear Bergen,and 73—76 off Bremanger
near Stad t .The Summer Neriti c Plankton on the Norwegian l i ttoral of the
lonema costatum .
Lindesnaes to Stadt, no previous studies had been made .
North Sea i s typical ly rep resented in the sampl es obtained byHJoa'
r ofl' Marsten (s t . 4) on the 26th June 1895 . This Plankton
i s ri ch in specie s , amongst whi ch most of the autumnal forms ofthe Skagerak are met with . But the rel ativ e conditi on s in respectto numbers are somewhat differen t. and some speci es , for instanceChw toceros Schz
'
ittii are replaced i n the North Sea by others,and
thus Chcetoceros Willet and Ch. rind -
um are characteri sti c forms ofthe North Sea littoral .
It wil l b e seen that , in th e Tabl es , we have div ided theNeritic Diatoms into Summer , Win ter and Arcti c forms . Thelatter are not met w i th in the Skagerak or on the North Seal ittoral , and the Summer and \Vinter forms are divided chi eflyaccording to the seasons in which th ey occur in greatest numbersin the Skagerak .
Samples of Plank ton from this fjord have been k ind ly p laced at our
d isposal by N oanou ap .
Even in the Skagerak , in which the Summer and Wi nter Plankton i s very d ifferent, the boundary between the Summer and theWinter forms i s not always easily d rawn
,and some indiv idual s of
tru e Summer forms (for instan ce C heetoceros (lidymum) may be metwith in the middl e of winter
,whil st Winter forms may be encoun
tered in small numbers at the warmest peri od of the autumn .
CLEVE’
s Tables shew , however , that each species attains i ts max imum at a fixed period of the year . On the West Coast thi s isnot s o marked . We thus see that so late as the 26th June
,no
smal l numbers of true Win ter forms (Thalassiosira N ordenskio'
ld ii,
gravida, Cluetoceros d iadema ) are to be met with .
In the Bergen almost simi lar species are to be metwith throughout the enti re summer
,as those contained in the above
mention ed sample s from Marsten . From Table 3 , St . 73—75 , i twil l al so be s een that a l ike plankton
,i f even somewhat poorer
,i s
to be found al l the way up to Bremanger, where , i t keeps butcl ose in to the coast , which however agrees with the fact that i tcon si sts of Neri ti c species .
An impressi on of the W i nter Neri tic Plankton of the WestCoast wil l be gathered from Table 5
,Stations 1 79—182 . The
sampl es of Plankton were col l ected by N ORDGA A RD whils t makingthe hydrographi cal section off Stavanger
,7th—9th February
and off Marstenen n ear Bergen (14th—15th February) . On thesurface the Plankton was stil l somewhat sparce, but a l i ttl e deep erdown , especial ly at the outer stations ( 181 , 184, where th eAtlantic water w i th i ts greater temperature comes nearer to thesurface (40 metres at Station there was found amongst theoceanic forms a considerably large number of Neri t i c speci es .GR AN found that the same kind of Neriti c sp eci es were abundantlydevel oped betw een Lindesnaes and Stadt in March 1898. Thesp eci es there were the same as those in the Skagerak
,the
quantative relati ons only being somewhat different . The Winterforms were not so paramount as in the Skagerak
,and there
was not so small a number of true Summer species amongs t them .
Thi s agrees wi th the hypothes i s that on the West Coast thevariat ion of the temperature between summer and winter i s n otso great as in the Skagerak
,the condition s on the l i ttoral o f the
North Sea , both in respect to hydrography and biology being moreoceanic , whil st in th e Skagerak they are more “ continental ”
,i f we
can employ thi s term in relat ion to an area of water .It i s possibl e too , that the bottom of the North Sea does not
present so favourabl e condi tion s to l ife as might be imagined . TheNorth Sea , as we may perceive from our charts
,i s al so to a great
extent fi ll ed with ocean ic bodi es of water . It i s a restl ess sea inwhich the boundary of the mud (J. Muaaax ’
s“m u d - l i n e ” ) i s first
met jw ith at a depth of 80 fathoms . The bottom con si sts for themost part of sand and gravel
,bare of al l higher alga - vegeta tion
,
notwi th standing that the d ep th i s n ot so great as to p reclude i tsgrowth if i t found a suitabl e soi l . It i s po ssibl e that the spore sfal l more easily to the bottom , and are retain ed in more tranqui lparts where the bottom is covered with mud at a depth of a fewfathoms . The only Neri ti c D iatom which appears in pl en ti tude in
the south eastern parts of the North Sea,i s a. speci es with large
and heavy spores,Biddulphia mobiliensis .
On the West Coast of Norway there are only some placeswithin the belt of i slands
,which are so shallow as to al low of
Outside i t thereexists the Norwegian Channel , and , in side i t, deep fjords where the
Thefjords
,so far as the investigation s hitherto made have shown , con
their favouring the growth of a Ner i tic Flora .
bottom temperature i s almost unvari ed throughout the year .
tain a very poor Plankton .
Finally we come to the seabord of the Northern Ocean whichform s a most decided antithesi s to the shal low Lim Fj ord with i ts
If on es studi es the Sea Charts,for
instance those of the coas t of Nordland,one will find that very
abundant Neriti c Plankton .
few ,and then only small shal low parts are to be met with . The
numerous i slands and rocks ri se almost invar iably perpendicularlyfrom a depth of 1 00 fathoms .
At such a depth the temperature i s almost unchanged throughout the enti re year ; thus the observation s taken off Lodingen dur ingthe years 1 879—8 1 (see MOHN , p . 91) at depths of 10 1)fathoms give the highest temperature (July 79) at the lowest
the annual variation being,therefore
,but at the outside .
At a depth of 50 fathoms (92 metres) , the variation i sin October
,in January) .
The boundary of the mud i s tee , off the coast of Nordland ,at stil l greater a depth , vi z . , 100 fathoms , than in the North Sea .
In our opin ion al l these condi tion s must be very untavourable
to the formation of Neri t i c Plankton .
In real i ty too,there are excessively few Neritic Diatoms on
the l ittoral of the Northern Ocean , compared with those on othercoasts .
Dur ing the summer of 1895, HJOR T studied the Plankton , alongthe enti re coast , from July to September . The results derived from
be found Tabl e 1,Stations 7—41 .
Moreover the “H a n s t e e n ” col lected. a number of sample s in June1896 (Table 3 , S tati ons 77 and the Swed ish Expeditions to
1896—97,coll ected Plankton off the Norwegian
coast i n June and August 1 896,and in May and July 1 897. The
hi s observations are to in
Spit z bergen in
contents of these sampl es were examined by C han : and the resul tspubl i shed in PETTER SSON and EKMA N
’
S late st work [98] Tabl es1—3 , pp . 48—5 I.
It wi ll be seen from all of these table s that small quanti ti esof Ne riti c Diatom s are to be met wi th
,during summer , al ong the
Norwegian shores o f the Northe rn Ocean .
No great pl entitude of ind ividual s w as to he found in any ofthe samples
,and only a few of them contained , mainly , Neriti c
speci es to any appreciabl e extent . One sample obta ined off theTrondhjem F jord in May 1 897, contained in fer alm
,mainly Chee
toceros ( labi le. and ano the r sample obtained off Ranen Fjord on the23rd May contained Skeletonema costatum .
Somewhat ri cher i s a sampl e from the harbour at Trom so,
obtained on the 12th June 1897,referred to by CLEVE in hi s
Phytoplankton p . 8.
con tortum,w hich i s a true Neritic species .
Its characteri stic form i s given as Ch.
Several of the speciesWi th almost these few
exceptions,the samples are nearly entirely free of Neri tic Diatoms ,
were found by CLEVE to possess spores .
1 5
The various varieties o f th is species (v ar. macroceros, longipcs , arctic/c,
Bucephalosj are not separated in m o st of the Tables .
but, on the other hand , some contain great numbers of Peridins
and Crustaceas , and others some Oceanic Diatoms , especially R hiz osole nia alata
, f. gracillima (R hiz osolem’
a gracillima, C1.) which onthe West Coast are characteri sti c of the Balti c current in summer.See our Tabl e 1 .
HJORT found that the Peridins and Crustaceas i ncreased innumbers as autumn were on , as the water became warmed in theneighbourhood of the land . Possibly the Peridins here replacethe wanting Diatoms , and in pl ace of them make use of th e lightand warmth of summer in forming a stock of nutritious elementswhich benefit the other organisms of the ocean .
It i s especially Cem tium trip os that occurs in greati t being a hardy and contented sp ecies whi ch i s to be found almostevery where in the North Atlantic Ocean at all times of the year .It i s , therefore , so far Oceanic , being enti rely independent of thebottom . On the other hand , i t probably requires so high a tem
perature to promote a great development as that which in highlatitudes i s only met with along the coast dur ing summer . Itmay , therefore , with u s , with a certain amount of truth , be call edNeri tic as it mainly appears on the coast .
The vari ety longipes developes i tsel f under opposite conditions ,esp ecially on our coasts , winter and spring , when the coastal wateri s cool ed , and the vari ety arctica i s the characteri sti c form in theArctic seas .
During the w i n t e r , our Northern Ocean shores are sti l l l essprolific in Neritic specie s than during the summer .
Of the numerous samples col lected by NOR DGA A RD in February,
March and Apri l 1896 —97 (Tabl e 5, Station s 186—198 . Tables6 and there are but some few (from Reine in Lofoten
,Station
2 15 and Stations 529—30 , l st Apri l 1 897) which contain Neriti cspeci es
,and these few speci es onlv in small numbers . The speci es
whi ch are to be found at that season are Arctic diatoms such asCheetoc cros fan
'
ccllatum ,Thalassa
’
osim hya lina, and F ragilaria ocefm ica,
as wel l as some which al so on our west and south east coastappear as winter forms
,such as Thalassiosim N orde'
nskie'
ldn,Th.
grav ida , Chaotoce'
ros sociale, debile, d iadema .
All these Speci es are l ikewise to be met with off the coastsof Greenland (s ee GR AN , 97. 2
In March 1898,GR AN found the same speci es in somewhat
greater numbers al ong the coast of Sendmore and Romsdal up tothe mouth of the Trondhj em Fj ord . This characteri stic PlanktonFlora thus appears to be spread along the whol e of our NorthernOcean seabord during March and Apri l
,i ts southern boundary then
appearing to be at Stadt..Neither in the number of species , nor in absolute quanti ty can
i t compare with the Plankton Flora which springs up at the sameseason in the Lim Fjord , the Cattegat , the Skagerak or even onthe West Coast , and which gives nouri shmen t to al l the Pelagicforms of larva which commence developing in spring .
Grea ter or l esser numbers of a remarkabl e Flagel lat , Phasecystis Pouchcti, (H an ) Lagerh.
,are almost invari ably to be found
together with these Arctic n eri tic forms . Its development i s as yet
unknown,and w e. therefore , dare not attempt to decide whether i t
i s of Neri tic or Oceanic origin . It belongs to cold s eas , but. duringthe winter , may he found down in the North sea , and even in smallnumbers
,i n the Christian ia Fjord .
A glance at our Tabl es wi ll shew that these Neriti c , Arcticforms are but met with , here and there , in smal l numbers , otherwiseall the samples contain but a non prol ific Oceanic Plankton (Coscinod iscus - species) .
On the whol e i t wi ll be seen that the quan ti ty of NeriticPlankton decreases in richness from the Lim Fjord to the Catte g atand Skagerak ; i s sti l l poorer on our North Sea l i ttoral , and ofi
the coast of Nordland dwindl es down to a minimum . It canno t bedue to the change to high northern latitudes . As w e have stated ,a v erv rich flora of Neri ti c D i atoms i s to be met with in KarajakFjord in North West Greenland . It can , therefore , but be due tothe bottom conditions
,and agrees with our v i ew s
,that the Ner i ti c
Diatoms demand such conditions of l i fe , that their spores are abl eto sink to the bottom
,be preserved there
,and subsequently
aroused again for development .
The O c e a n i c Organi sms form a con trast to the N e r i t i c .
The condition s necessary to exi stence in the open seas areless varying than in by the land . The temperature may ri se andfall w ith the season s . or as the bodi e s of water advance ; but thevariations proceed slowly . Stil l more sl owly do the changes in thesal inity of the ocean occur .
The ocean , therefo re also posse sses a Plankton much moreuni form than that met with on the coasts . So long as i t remainsin the same current , the composition of the Plankton vari es v eryslightly .
The Pelagic organi sms do not requi re any means of protectionagai nst the variati on s in the temperature and salini ty . Each individual specie s may he adopted for l ife wi th in v ery narrow lim itsof temperature , yet nevertheless find an immense area in which i tcan develop i tself abundantly .
The Pelagic D i atoms which we shal l sp ecial ly treat of,may
,
l ike other diatoms , become devel oped in enormous numbers atcertain times . When a rich D iatomic Pl ankton i s met with in theocean , i t wil l be found to contain
,as a rul e
,on e or some few
Species i n overwhelming numbers .According to Scuii'rr there l i ve
,during summer
,in the
Irminger Sea vast numbers of Thalassiothrix ln issima, and often ,i n the North Atlanti c , Chastoceros decipiens or Ch. boreale may bemet with developed in equal ly great numbers . Other specie s mayoccur amongst these masses , but o ften in qui te an insignificantn umber .
At other times great stretches o f ocean can he almost enti relyfree of D iatoms . In such a case the condi tion s for the d evelopmentfor these organi sms can hardly be favourabl e
,as some indiv idual s
are to be met with everywhere which,i f the conditions were favourable
,
could be the origin of a rich vegetation .
The Oceanic Di atoms which are of some importance in theNorwegi an Northern Ocean are not many .
As we wil l set aside rare speci es , we n eed but to tak e thefol lowing 1 6 speci es into account :
16
Coscivwd iscus comm-
nus. W . Sm.
oc ulus i-rid is . Enn.
rad iatus EH R .
stellatus,Ror.
R hiz osolen ia stylifomnis , BR IGH TW .
scmisp ina, HENSEN .
Shrubsoli, CL .
alata ,Barcnrw . , f. gracillima
obtusa, HEN SEN .
Cheetoceros boreale, BAIL .
(including Ch. Brightw elln , CL .)
criophilw n, CA STR .
(incl uding Ch com ‘
olutum, GASTR . Ch.
GRAN , which i s however regarded , bydifferent Speci es) .
currens, CL .
atlantjcum, CL .
decip 'iens , CL .
Tha lassiothria' F rauenfeld'u ,GRUN .
longissima, CL . GR UN .
It w ould not appear as i f all of thes e speci es were favouredby the same outward conditions . As a rul e not more than one orsome few species are to be met with in quantiti es
,whil st the others
then are but secondary elements of the Plankton .
It i s thi s ci rcumstance,w hich gave CLEVE the idea of separa
ting h is types of Oceanic Pl ankton (see inter alia p . whichwe in the fol lowing enter i nto at greater l ength . There are esp ecially fiv e sp eci es w hich can appear in such numbers as to gi v ethe Plankton i ts character ; namely
Coscinodiscus oculus iridisThalassiothrix longissima
Chcetoceros decip iensR hiz osolenia stylifw mis
R hiz osolenia alata (f. gm cillima) .
Those hydrographical condi tion s which in different in stancesgive s one of these Speci es the priori ty of the others
,hav e not yet
been investigated . In many cases the temperature appear s to playan importan t part, ev en i f thi s i s not p er se capabl e of exp lainingeverything .
The Coscinodiscus sp ecies , thus occur on our shores , especial lyduring th e coldest p eriod of winter ; after these come Thalassiothm
’
x ,
and somewhat l ater on the Oceanic Chcetoreros speci es , whil st R hiz osolen ia styliformis , arrives with the Atlantic current during thesummer and autumn , and R h. (data thrive s best in the very warmsurface layers which the Baltic current conveys along the coast
(see Tabl e 1 ) during summer .The resul ts derived from the two “Heimdal expeditions in
May 1896 and 1897, al so agree with the above .The distribution of the Plankton is graphically described on
PI. 4, in the Hydrographic Profil e s .Under each Hydrographic Station wi ll b e found two columns
,
of which the first,on the l i st
,denotes the surface Plankton
,the
other , the contents of a sampl e taken in a net drawn perpendicularly to the surface from a depth of 100 metres . The Oceanic
speci es are coloured blue,the Neritic red (Southern) , brown (Nor
thern) and green (Arctic) .The tones of the colours denote the app roximate quantity of
the corresponding species,the name of which will be found at the l eft
,
j ust beyond the horizontal l in es . The tones correspond with the 4mark ings given by CLEVE , r (l ighte st) , (2 tones) , c (3 ton es) ,cc darkest tints . Of the green colouring there wi ll be found butthe two l ightest shades
,and of the brown but the three l ightest .
It must be stated that CL EVE ’
s markings , which we have ,hi therto
,adopted in all our investigation s
,but form a very small
scal e for the compar i son of the quantitative di stribution of the specie sin the samples . The indication cc , corresponds to a frequency whichis at l east 1 000 times greater than denoted by r . Neither theTables
,nor the graphic deliniation on P] . 4 , give , therefore , an
adequate idea of the diversity,which
,in real ity
,i s very great .
On Pl . 4 , it wi l l be seen that the temperature in 1 896 , in
creases from the coast outw ards toward s the bod ies of water inthe Gulf Stream
,after w hich it gradual ly decreases as it approaches
the Polar current . The same was the case in 1897,with the
exception that the temperature was,throughout , about 2 ° l ower ,
owing to the greater development of the Polar current .In 1896
,the Oceanic Diatom s were so di stributed that Chm
toreros (lecipicns attain ed i ts maximum at St . V (surface temperature Tha lassiothrix longissinm between St’ s . VII and VIII
(Temperature respectively 6° and and Coscinodiscus ocu lus
iridis at St . VIII (Temperature The Rhiz osolenia styliformés
was not met with at any of the stations in great numbers . Itattains i ts greatest development somewhat later in the summerwhen the water has become more heated .
In May 1897,non e of the species had become devel oped to
any appreci able extent .We thus see that each individual species attain s its maximum
at different places , and under d ifferent conditions ofi
life . Probablyit is the temperature whi ch has th e greatest influence on thei rdevelopment .
As the various Oceanic currents do not afford the organismsl ike conditions of exi stence , the Plankton may , in many instances ,be employed as a means of di stinguishing waters of different origin .
The Di atoms may easi ly be observed,especially on account of
thei r occurrence in masses,and their var i ous appearances at vari ou s
spots may , in many in stances , stamp the Oceanic currents .Thi s i s i l l ustrated , too , on PI. 4 , Fig . 1 . The Stations II
IV*) are near the Norwegian coast , and the coastal currents withtheir low sali nity go from the surface down to a depth of 60 to1 00 metres .
The Plankton contains scarcely any diatoms,only some indi
v iduals of Ocean ic speci es , but, on the other hand , great quanti ti esof perid ins , (especially Ce mtium tripos and the vari ety longipes ,
which however i s not separated from the main Speci es) .Stati on s V are situated in the waters of the Gulf
Stream , as will b e seen from the dark blue colours on the profil e
(sal inity exceeding 35
On the Tables , S tations 42—46 .
On the Tables, S tat ion s 46 , 50, 54.
1 7
The samples of Plankton contained masses of Diatom s,and
no app reciabl e difference ex isted between the surface Plankton ( l stcolumn ) and that of the deep (2md column) . Amongst the Oceanicspecies , not a few Neri tic species were met with , which in suchsal t water found favourable conditions of growth . They would probably , however , have proceeded further with the current for a shorttime , as most of them possessed numerou s spores . (Chastoceros
cinctum,constrictum, diadema) .
At Stations VIII—IX , the Atlantic water was covered byfresher Arc tic Ocean water (light blue colouring) , which , however ,then formed bu t a layer of about 80 metres in thickness . ThePlankton there was poorer both in quantity and qual ity . TheNer iti c Diatoms were enti rely w anting, and the Oceanic were somewhat scarce on the surface
,whil st met with stil l in great numbers
in the samples taken from a depth of 1 00 metres to the su rface.
In procuring these samples the net w as thus drawn through partlyAtlantic water .
Stati ons X—XI,furni shed an excessively poor Plankton yielding
but quite few individual s of the most hardy forms . In the ArcticOcean water therefore , the Diatoms had not at that peri od of theyear commenced their devel opment .
In May 1 897 (P1. 4 , Fig . 2) the Arctic Ocean water was sti l lvery deficient in organi sms
,and even in the Gul f Stream
,th e
development was del ayed on account of the cool ing influence ofthe Polar current .
From these examples i t will be seen that a study of thePlankton , together wi th purely hydrographi cal investigati ons ,
”
maybe of great value in discerning layers of water of differen t sourcesof origin , in the present in stance too , the water in the Norwegiancoastal currents
,the Gulf Stream and the Polar current .
In other in stances , how ever , the Plankton gives but l i ttl e information concerning the Ocean currents . Thus , for instance , boththe Gulf Stream and Polar current are very d eficien t in Diatoms .Thi s wil l be seen , for instance
,i f Tabl e 7 be compared with the
corresponding Table B III (F ig . or with the p rofi le Pl . 5,
Fig . 1 . The specie s which occur are the same in both currents,
whil e no considerabl e quantitative difference can be observed .
If the inv estigations in respect to the Plankton are to be employed to any great extent as hydrographical aid s
,the l ife and
di stribution of the Plankton organisms must be first thoroughlyknown
,as
,otherwise
,hasty conclusions m ight be drawn from them .
Firstly,the Oceanic Plankton changes its character with
the seasons,j ust as does the l ife of pl ants and animals on the
coasts , so that the same current at different p er iods of the yearcan con vey with it different org anisms , for instance into theNorth Sea .
Secondly,the very same current becomes gradually chil l ed or
heated during its course ; possibly al so undergoes sl ight changes 1 1)
i ts salin ity and gaseous contents . On Pl . 4 , Fig . 1,it wil l thus be
seen that the temperature and sal in i ty of the Gulf Stream decreaseas its waters app roach the Polar current .
Such changes wil l,no matter how gradually they occur , affect
the nature of the Plankton,as they retard the development of some
speci es,and promote that of others whi ch poss ibly may have , pre
viously, appeared in such smal l numbers , as to have escaped
attenti on , or which . as regard s some ind ividuals. have entered thewaters from adjacent currents .
In th is w ar one can . in any case . most easi ly explain thegradual changes in the composition of the Plankton , as w e knowit
.from the g reat oceanic currents , especia lly the Gul f Stream
( see J . Mrauav 97
It i s . therefo re , necessary to make full er investiga t i ons respec tingthe ex tent to which the Plankton organisms can trav el in that stratum of w ater to which thev belong ,
w i thout thei r being destroyedbv the change of cond it ions .
A ccm'd iug to PETERsI-zx’
s inv e stigati on s . the va ri ous organi smsdo not possess equally great powers o f standing such changes .Whil st large animal s . such as the medusa Pilema octopus arecarried along al ive , du rin g Autumn . with the bodi es o f wate r which
flow from the North Sea into the Lim Fjord , and al so whil st A’
octiluca
i s carri ed in , in great numbers the Diatoms of the North Sea (duringthe Autumn Rhiz osolenia styl iformis) only come as far as the neareststation at the entrance of the Fj ord .
As the water invariably fl ows from the North Sea through theLim Fjord to the t
'
attegat. the Diatoms arriv ing from the NorthSea must peri sh in the western porti on of the Lim Fjord .
In the central part of the Lim Fjord they are replaced by ari ch Neritic Flora , w h ich however , in its turn cannot proceed furtherwi th the water to the Cattegat , bu t sinks to the bottom before i treaches the eastern mouth of the fj ord .
Thus in the Lim Fjord the movemen t of the Diatoms i s l imi tedto a most con siderabl e ex tent . In that fjord the condi tions of l ifebecome changed with great rapid ity , as , for in stance , the sal ini ty“)can decrease from (Stati on 2) to (at the ea sternStati on) .
In the open sea . the Diatoms might well t raverse verv great
areasOur great est interest i s centred in our acquaintance with the
changes tha t take place in the ocean currents al ong the coasts whereou r great fi sh eries exi s t . And w hen the oceanic bodi es of water
approach the land they must undergo hydrographic changes whi chare suffi ci ently great to change thei r D iatomi c flora .
Contac t wi th the bottom , and with other currents must , there ,supply the w aters with the germs of a new Plankton , which , insuch a case . deve lop rapidly . Seve ral observati ons have been madewhich ind icate that the Pl ankton increases in bulk where vari ousocean ic curren t s meet (see , amongst oth ers , PETER SEN [98] pp . 14 ,
VA N HGF F Ex and our own observations from the WestCoas t , Table
In indi vidual cases i t may , therefore , be very diffi cul t to deterO c e a n l c T y p e S
mine which forms have been carri ed in with the oceanic currents ,and which have been previously latent , as spores on the bottom orsingl e indiv iduals floating i n the coastal current .
1 ‘ Sim - Plankton (symbol Si) ‘ Typical forms
Of late Swedish scienti sts have come to tolerably advancedconclusi ons respecting the di stribution of the Plankton
,and , mainly 2 Tricho - Plankton
on these . built thei r hypotheses of the system of currents of theNorth Atlantic .
M m“ [981 Table I.
3 . Chwto- Plankt on
The i r v i ews have been gi ven i n several work s ; first in thoseo f A UR IV ILL IUS based on th e an ima l Plank ton , subsequ en t lyin those of CLEVE [97] whi ch are based exclu s i ve ly on th e d istribution o f the D i atoms . Var i ous phases of th e hyp oth es i s hav e
,
moreover , been d i scu ssed in the wr i t i ngs of Cs r: , EKMA N , throwand Parrs assos concerni ng th e cond i t i on of the Skagerakdu r ing the per iod of the H err ing fish ing , and a l so i n PETTERSSONand EKM A N
’
S two l ast treati ses on th e subject [97 andThe hypoth esi s may, shortly , be ind i ca ted by saying that the
layers of water in the North A tl anti c mov e betw een each o ther w i thou tbecoming mix ed to any great exten t , except i n the sha l low s on thecoast . They can b e recogni sed by the i r Plank ton organ i sms
, just
as geo logi cal strata are d i st i ngu i sh ed by the i r l eadi ng foss i l s .
When tho se var i ou s types o f Plan k ton,whi ch in Summer a re
to be met wi th i n different geograph ical areas i n th e North Atl an ti cand on i ts seaboard
,occur
,p er i od ical ly , in con secu ti v e order i n
th e Skagerak , this i s con t ingent upon the var iou s l av ers of waterflowing i n from each i ts geograph ical pal e .
Th e southern N er i t i c spec i es wh i ch frequen t th e Skagerak i nSeptember . October and Nov ember
,shou ld thu s enter i t from th e
sou thern p orti ons of the North Sea along th e roast o f Ju tl andtogether wi th ocean i c forms from the eastern parts o f th e A tlan t ic .
In November,som e north ern N er i t i c forms ought to arr ive
,
p robably from th e Norweg ian coast,as we l l as Cen tral A t l ant i c
form s (the so- cal l ed Chasm- Plan kton) ; in December , W' est A t lan ti c
oceani c speci es (Tr i cho - Plank ton) , and , i n February , Ocean i c andN er i ti c speci e s from the coast o f Green l an d (Sim - Pl an kton) , whi chmust
,th rough the in creased bulk of th e Po l ar curren t , be conveyed
r igh t across th e Gul f Stream .
Du r ing th e course o f th e Spr i ng , th ese ar e surplanted by th eCen tra l At l an t i c Plank ton , and N er i t i c form s from n orth ern shore s ,and
.dur i ng the summer , th e. East A tl an t ic speci e s reappear i n the
d eeper strata,whi l st the organ i sm s of the Bal ti c curren t (Tr ipo s
Pl an k ton ) fill th e l e ss sal i ne waters of th e su rface .
In h i s l ast great and comp reh en s ive work , A UR IV ILL IUS g ive sa descr ipt ion of the Animal Plan kton of the Skagerak
,from the
study o f wh i ch he has arr i ved at s im i l ar resu l t s , w h i ch we wi l l referto i n our con cl ud ing remark s .
We wi l l now enter more fu l l y i n to CLEVE ’S hypoth eses , i norder to See whe ther they , i n ou r op in ion , can be ma in tai ned .
CLEVE recogn i se s th e fo l low ing typ es of Plank ton .
19
4 . Styl i - Plankton (symbo l s) . Typ i cal iorms
5 . Tr i pos -Plan kton
N e r i t i c T y p e s
(symbo l Nm) . Typi cal form s
nus
Styl i - Speci es R hiz osolenia styliformis w as foun d i n 1 0 samp lesWe wi l l first refer to the Ocean i c Type s .
Cliaeto[ Chwtoceros boreale . 4
A s we h ave al ready stated , the cond i t ion s in th e open sea are l dec apiens 6
s im i lar th roughou t great stretche s of ocean . and i t common ly hapTr i cho [ Thalassiothriaz “Wm 5
pen s tha t one specie s predom inates to such an exten t as to d eter t iz osolenia scmispina . . 3
m ine th e nature o f the Plankton . Th erefore such a cla ssi fi cation Tr i po s R hiz osolen ia gracillima 4
a s tha t made ou t by CLEV E i s practi cal an d app l i cabl e in manyinstan ces , even i f one d iffers from h im in the hypoth eses attachedto i t .
Be fore p roceed ing further , w e wou ld remark that CLEVE ’S type,
S i r a P l a n k t o n , i n cl udes Ocean ic (Coscinod iscusgl and Ner i t i c (Thalassios ira) form s . For th e ocean i c
,on e ough t therefore to estab l i sh
a n ew type,D i s c o - P l a n k t o n . and place S i r a - P l a n k t o n amongst
the Ner i ti c forms .
Wi th th i s change , Chs v s’
s 5 type s natura l ly embrace th e 5Pe l agi c D iatom s wh i ch , a l so , from our observ at ions
,mos t genera l ly
occur as p reva l en t speci es in the Plankton .
We thus get
1 . Di sco - Plank ton C‘
oscinol liscus oculus iréclis6
2 . Tr i cho -Plankton Tha lassiothrix long iss ima
3 . Chasm- Plankton Clire toceros d ecip iens
4 . Sti - Plankton R hia solcn ia stg/ liform is
5 . Tr i pos- Pl ank ton Rhiz osolen ia aluta
A decid ing ques t ion as to th e correctness o f CL E VE ’
s hypothesi s con cern ing the movements of the Plank ton may be pu t
,v iz .
,
whether a type of Plan kton o r Plank ton commun i ty i f we mayuse a term employ ed for the fixed p lan ts canno t become Spreadi n o ther ways than by mean s o f the ocean curren ts . If CL E V E ’
S
th eory were r ight,i t su re ly ought to b e prov ed that the D iatom i c
commun i t i es canno t sp r ing up to any great exten t in parts remoteeach o ther . even i f th e natural con d i t i on s were sim i lar . In sucha case one m ight , just i fi ab ly talk , for i ns tan ce , of Cha:to - water andTr i cho - water
,i n wh i ch th e organ i sm s cou ld be regarded in the
same l igh t as l ead i ng fossi l s i n geo logi cal strata .
The Swed i sh sci enti sts hav e no t endeavou red to be ing forwardany proo f
, of th i s be ing so , and , i n real i ty , such cou l d no t he don e .
On th e con trary, CL EVE
’
S own tabl es sh ew u s the po ssi b i l i ty of suchi ndependent dev el opm en t .
If bu t qu i te smal l numb ers,for i n stance of Chas to
,D i sco and
Tr i cho Plankton speci es cou ld be found amongst an abundan t Styl iPlan k ton
,the poss i b i l i ty i s rai sed of the o ther speci es becom ing
gradual ly dev e loped at the expen se o f th e S tyl i - Plan kton wh enthe waters coo l or poss ibly undergo other
,bu t h itherto unknown
hydrograph i cal changes . The opposi te wou ld occur by an in creaseof warmth
,and even i n th e Po lar current i tse lf a Styl i - Plankton
m igh t gradua l ly become deve loped prov ided i t con ta in ed some ind ividuals of R hiz osolcnia stj/ l
fiformis whi ch had surv i ved the co ld,
or wh i ch m ight en ter i t from adjacen t curren ts .
If we regard CLE V E ’
s Table I [97] in wh i ch he has p laced anumber of, in h i s op in ion
,typ i cal samp les of S t y l i - P l a n k t o n
from th e mos t d ifferent por t ions of the A t lan ti c,we wi l l perce i ve
that in th e 1 2 samp l e s the fo l lowing were m et wi th .
In Table II,7 Types of Ch em o - P l a n k t o n
Cluetcccros boreale was found in 7 samp l esI decipiens 7
C'
oscinod iscus ocu lus irid is 1
ITil -i i lassiothi 'ix longissima 5
l Bhiw solcnio seinispma 4
s ly/iformis
i-
l
—O'gracil/ima
Of T r i c h o - P l a n k t o n,p . 6 , 10 Typ i ca l sampl es
Tlmlnssiothriac longissima w as found in Gsamples
l Rhiz osolcn ia semisp ina 5
Cosc i nod iscus oculus irid /is 2
j Chw toceros boreale 3
I decip iens 2
R hiz osolen ia sty/ l'iformis 3
I t wi l l be seen tha t even in these samp le s w h i ch CLE VE h imse l f ha s cho sen
,there are suffici en t of the oth er Plank ton Com~
munities to a l low o f the ir becom ing d eve loped when a change inthe cond i t ions o f exi s ten ce occurred .
In nature , the commun i t i es are, in most in stan ces , even sti l lmore m i xed
,even when one predom inates . I f one refers to our
Pl . 4 ,Fig . 1
,i t wi l l be seen that at S tation V
,th e Cheeto - Plank -
i
ton predom inates,wi th Tr i cho and D i s co - Pl ank ton i n a subord inate
degree . A t Station VI,th e same exi sts . At Station VII the thre e
Ocean i c typ es are equ a l ly dev e loped . At Stati on VlII,the D i sco
and '
h icho- Plan kton pr edom inates,Wi th Cheeto and Styl i - Plank ton
to a subordin ate extent .
At Sta t ion IX. th e Tricho - Plank ton predom inates , the thr eeoth er commun it ies onlv in a subord inate degree . A t Stati on Xverv smal l quan t i t ie s o f bo th '
l‘
richo Di sco and Chmto- Plan ktonare met w ith . but non e of th em predominat ing .
It was th e same at the fo l low ing St at i ons wh i ch were estab l i sh edat d itiereut spot s in the sea l ing area . Such so l i tary members of
the var i ou s Ocean ic D ia toms are to he me t wi th almost ev erywhereth roughou t the No r th A tlant ic Ocean at a l l seasons of the year .
Thus Vaxuiirrs x du r ing m idw inter , up the Karajak F jordin West Greenland , found so l i tary i nd i v idual s
,at on e t ime o f the
('
h¢etoccros dec ip iens . boreale or atlanficum, at an oth er of the Rhiz osolen iu styli/brmis or semisp iua , and a l so of the Coscinod iseus oculusirid is and rad iatus .
I t was a l l a chance w h eth er the n et brough t up one or o therof th ese spec ie s . as they were very scarce (see Vaxnorrns ’
s Tab l el c, p . 288, and Gnax [97.
ou r assum ing that th e var ious Ocean ic D i atom i c commun it i es canTh ere i s thu s n oth ing to preven t
becom e d eve loped i ndepend ently i n qu i te d ifferent loca l i ti es .
From th i s i t i s concl u s i v e th at the d i str i b uti on of th ese communities canno t be emploved i n form i ng concl u s ions concern ing th econn ect i on of cu rrents th rough wide ly separated tracts of Ocean .
The Typ i ca l form s in CLEVE’
s Type s are so w ide ly sp read thatthe ir occurence i n masses canno t
,as a ru l e , ind icate tho se parts of
th e ocean i n wh ich th e stratum concerned or ig ina ted .
A t short d i stances,wh ere th e hydrograph i cal con di t ion s are
not a l lowed t im e to change,th e Pl ank ton may , however , y i e l d
verv im po rtant in formation . Thus i t i s kn own th at great quant i t i es of cutt le fish and medusaz are con veyed , dur i ng th eAu tumn
,to th e Skagerak from the Nor th Sea an d Engl i sh
Chann e l .The se l arge an imal s h av e greater powers of r esi stan ce th an
th e on e - ce l l ed D iatom s,but th e same curren t carr i ed wi th i t too .
an abundan ce of Sty l i - Plank ton , wh i ch conta in ed marked sou th ernforms . Thu s . th e Ocean i c R hiz osole nia, robusta , N orm
, was foundoff Langesund on the oth Nov ember 1897. It i s common in th eMed ite rranean bu t no t me t w i th p rev iou sly i n a h igh er n orthernlat i tude th an off Plymou th .
But such m igrat i on s o f th e Plank ton commun it i es can on ly bedeemed po ss ib l e
,prov id ed the cond i t i on s of l i fe remain somewhat
u naltered . On l engthy jou rneys , the cond i ti ons become changedwe n eed on ly to look a t th e chart s to see how th e temperature of
the Gu lf Stream d rop s as i t approach es th e North an d th ePlankton organ i sm s be surplanted by o ther spec i es .
It i s qu i te ano ther matter that , owing to th e D i atoms be i ngv ery sens it ive to hyd rograph i cal var iations , the i n ves tigation of theP lankton
,comb ined w ith read ings of temp eratu re and ch em i ca l
r e earch becomes a mean s o f study ing th e hyd rography of th evariou s ocean cu rren ts .
Thus i n t e r a l i a ,our Pl . 4 , shews that two adjo i n ing ocean
cu rrents can po sses s a very d ifferen t Plank ton .
But as the Plankton organ i sm s are depen dent on the hydrograph ical r e l at i on s (temperatu re , sal in i ty) they cann o t en l ighten u son any po int o ther than what we a l so cou ld d i scover by accu ratehydrograph ical inv estigati ons .
Given equal cond i tions , the same Plank ton organ i sms w i l l become deve loped prov ided the n ecessary germs a re present
,and th i s
fact as a ru l e ho l ds good i n respect to th e Pe l ag ic D iatoms .In respect to th e N eri tic D ia toms the cond it ions are much
more comp l i cated,as th ey possess many more spec ies . CLEVE re
cogn i se s 5 type s .
1 . D i dymus - Plank ton or Sou thern Ner i t i c Plank ton (Nm) Typ icalForms
Chaatoceros (lidymum
curvisetmn
Schuttii
B iddulph’ia mobiliensis , and o th ers
2 . Northern Ner i ti c Plan kton (Ns) wi th i t s Typ i ca l FormsL ep tocg/ lindrus danicus
Skeletonema costatum
Chw toceros lacin 'iosum
Laudcria annulata
3 . A r ct i c Ner it i c Plan k ton (Ng)A clmanthes twa iata.
F ragilaria oceanicaCheetoceros fw
'
cellatum
Tha lassiosim hyalina
4 . Concinnus - Plank ton (No)Coscinodiscus concinnus
B'iddu lph'ia mobiliensis
5. Halosphazra- Pl ank ton (N11)H alosphaz m
' irid isTo wh i ch m u st h e added
6 . Sim - Plank tonThalassiosim N ordenskw ldu
grav idaChaztoceros cliadema
sociale
CLEVE has in clu ded th i s i n the Ocean i c D i s c o - P l a n k t o n .
A ll th ese Ner it ic typ es of Plank ton,wh i ch at d ifferen t t imes
are m et wi th in Skagerak,are suppo sed to be i n constan t movement
w ith the cu rrents , but non e o f th em are sa id to proceed from theSkagerak i tse l f. CLEVE say s p . 3)
“These N er i t i c form s mo vew i th the cu rrents a long th e coasts
,and I b e l ieve th ere ar e n o
stationary spec ies among th em .
”
Thus Type No . 1 (Nm) i s p resumed to enter th e Skagerakfrom the south ern parts o f th e Nor th Sea ; No . 2 (N s) from th eWest Coast of Norway ; No . 3 (Ng) be longs to th e A rct ic shoreso f Green l and an d Sp i tz bergen ; No . 4 an d 5 , th e North Sea , andthe S ire - Plank ton , i t i s presumed , comes from the Coast ofGreen land .
Non e of th e Types therefore are suppo sed to be long to th eSkage rak i tse lf. and ye t there i s foun d there a greater mass of
N eri t ic P lank ton than i s to be m e t w ith at any o th er spot on th eseaboard of the North Sea or North ern Ocean . It i s only th eCattegat and the Lim Fjord that possesses Ner it i c Plan kton i ngreater abundance .
February . If this migrates di rectly across the Gul f Stream . fit
must thus take 5 months to perfo rm the iourney, and during thatpe ri od be exposed to grea t hyd rographical changes . It has , however,n ever as yet been observed on its w ay , so that there ex ists nothingw hatsover to al l ow of our assuming the probabil i ty of such amigration .
“ e therefore , have come to the conclusion that the PlanktonDiatoms cannot be used as indicatory organi sms in the compar i sonof far separated places , as thei r migratory powers are not great ,and the same k inds o f Plankton can
,in all probabil ity , be deve
l oped at different places und er l ike condi tions .With the large animal s of the Plankton , matters are , however ,
very difl‘
erent. The Animal Plankton has been very thoroughlygone in to hv A t'mv tLs ,
who . especially in hi s l atest great work
[98] gives a general account of thei r relation to the ocean currents .
A L’
Biv iLL i t'
s bases hi s observation s on the Plankton of theSkagerak . which is partly endogenous , and partly allogenus .
The allogenus specie s he separates into 5 group s .1 Forms from the Jutland current .2 . Forms from the amalgamated waters in the Northern Ocean .
3 . Forms from the no rthern parts of the Gul l Stream .
4 . Forms from the Arctic curren t .5 . Forms from the Baltic waters .Thi s classificati on has been partly founded on the di stribution
o f the species in the No rthern Ocean &c .
, which however , i s tosome extent but l ittl e known , and partly , and especial ly on thei rperi odical appearance in the Skagerak .
Thus for instance,the forms in the Jutland current a ttain
the i r maximum in September—October ; those of the Arctic currentin F ebruarv .
The Author,however, says (I. c . p . 1 27)
“W'enn l'erner dieErscheinungszei ten der Formen einer jeden di eser funf binn enJahresfri st auftretenden Klassen unter s ich vergl ichen werden , sogeht hervor ( lass si e n icht in der Meinung von einander gesondertsind , dass die einc au ftri tt. w enn di e andere ve rschwindet oder imBackgang begrifl
'
en i st , sondern vielmehr gre ifen di e Per i oden ineinander tibe r so (l ass gl eichzei tig his auf vier Kategorien vertretense in konnen. So i st z . 8 . im Januar d er F all
,w o noch ein ige
Formen der Jiitschen Stromung z u tretien sind , wahrend dass
gl eichzeitig all e drei Gruppen nord lichen Ursprungs mebr oderw eniger zahl reiche Vertreter haben .
”
In this , in our op inion , l i e s the kernel of the question . We
consider i t as settl ed that , throughout the vear , bod i e s o f oceanicwa ter flow into the Skagerak , especially along the coast of Jutl andw here the strong current which pours in has long been recognised .
And the wa ter must convey w ith i t Ocean ic organi sms , providedthey have suffici en t powers o f resi stance to withs tand the changestha t occur in the surround ing water .
But we regard i t as being doubtful,whether
,from the sol i tary
spec ies o r group , i t i s possible to ind icate w i th ce rtainty the pal eof sea , or the ocean currents from which they originate .
Two stretches o f ocean or land . with not too different a climate ,own , as i s known , most species in common , whil st but a minori ty , ofmost often rare , sensi tive forms , are typical o f indiv idual spheres .
And even were i t possibl e with certainty to say that certainspeci es but existed , for in stance in the Polar cu rrent (such asCalanus hyperbm
'
eus , Clione l imacina) , one cannot , therefo re , ei therin the North Sea or Skagerak poin t out certain layers of wateras being
,or having been direct continuation s of the Polar cu rrent .
This current shews its influence by giving the northern portion of the Gulf Stream a lower temperatu re and lesser sal inity thanel sewhere . We saw on Pl . 4 , that the great development of thePolar cu rrent , during the winter and spring of 1897, lowered themaximum temperature on the l in e Sogne Fjord—Jan Mayen (1 2thi5th May) to w hi l st in 1896
,at the same pe riod i t was
The Polar current i s checke d to the north of the Shetland Islands,
but as al l the Arctic o rgani sms can thr ive in water of 5° to 7°
(see A UR IV ILL IUS l . c . p . 87 they may be conveyed on inthe amalgamated layers to the North Sea and Skagerak .
As A unrv umius , gen erally finds his geographical groups intermingl ed
,th i s su rely l ikewise indicate s that the waters become
mixed , and that i t i s , thereby , impossibl e to point out strata ot'
any
certai n origin .
The ocean ic waters which fl ow into the Skagerak must pass ,partly . through the Engl ish Channel , partly through the northernentrance to the No rth Sea , and the Norwegian Chann el . Thenatu re of the iii - fl owing layers are therefore d etermined by thehyd rographical condi tions ex i sting in those parts .
There, as eve rywhere el se the changes of the season s affect
the ocean water and its organi sms so that the temperatu re . andthe Pelagic Fauna and Flora obtain an annual peri od . This comp lication alone can
,i n our opini on , cause great yearly changes in
the Plankton of the Skagerak . To this must be added the fact,
that the Gul f Stream during winter. in th e northern portion ofthe Nor th Sea
,becomes chil l ed by the proximity o f the Arctic
curren t,and that
, possibly , i ts fauna is suppl emented with Arctican imal s .
The biol ogi cal conditions can , thus not affect the resul ts o fou r hyd rographi cal stud ies . The general resu lt of the combin edinvestigations we may sum up in the fol lowing manne r .
R e s um e
Hydrographical Conditions i n the Northern Ocean are determined by three factors, viz .
,the Gulf Stream ,
thc Arctic Currentand the Continent . The influence of each of these factors i s subjectto annual period s having their maxima and minima .
T h e G u l f S t r e a m reaches i ts maximum during the summer .
It then attains tho se dimensions with which we have been madeacquainted through the instrumental i ty of the Norwegian NorthernOcean Expediti on . In November i t begin s to decrease and by thewinter i ts th ickness
,both on the surface and down in the deep ,
dimin i shes . Wh il st i t , during summer , covers the greatest portionof the surface of the Northern Ocean , i t in winter becomes reducedto a narrow s tripe running in the d irection SS\V to NNE,
throughoutthe central and easterlyl portions of the Northern Ocean . But ,n everthel ess
,i t forms a barrier at all times of the year between
the East Iceland Arcti c current and the North European coastalsea . In the d eeps of the Norwegian coast the annual period i sseen through its being met with
,during summer , up to 50 metres
below the surface,whil st , during winter, i t sinks to a d epth of 2H0
to 250 metres .In addition to the annual period , the Gul f Stream , according
to our investigations,l ikewi se undergoes changes from one year to
another,but we canu vt , from the materi al s to hand , determ ine
whether these vari ations are connected w ith a great period or not .The eastern branch of the A r c t i c c u r r e n t (to the eastward
of Iceland) i s forced hack during the summer , so that it but reachesthe south eastern poin t of Iceland . During winter
,on the other
hand it attains so great dimension s during March and April , asto occupy the whol e of western portion of the Northern Oceanfrom the surface down to a depth of at l east 2 to 300 m etres . Duringthi s peri od
,as in 1897, i t can descend so far in a SSE direction ,
as to be separated from the Shetland Islands by but one degreeof l ati tude . There
,however
,i ts course i s always checked by the
northern branch of the (nlm S tream,but probably a great admix
tu re of thei r w aters occurs .
Thi s current too , i s subject to great changes from year to year ,and these changes are most cl o sely connected with correspondingchanges in the Gul f Stream .
T h e C o a s t a l W a t e r,along the entire coast of Norway
,under
goes the same annual peri odical changes as previou sly described byHJOR T The most striking phenomenon in thi s peri od i s theincreasing thickness of the coastal water during the autumn and
win ter , whil st the Gulf Stream is simul taneously forced down towards the bot tom . From our investigations
,thi s expansion is
chi efly caused by the mixing of Atlantic water with fresh waterfrom the continent
,and not by the !addi tion of water from the
Arctic Ocean as i s assum ed by PETTER SSON and EKMAN .
The Plankton. In the foregoing pages we have given an accountof the vari ou s kinds of v egetabl e Plankton exi sting on the shores ofNorway . and the annual peri odicity in the occurrence of the individual Plankton organi sm s .
Of more general interest are our enquiri es into the causes ofthi s p eri odicity . It i s caused on the one part by the stationarycoastal forms ’ depend ence on the physical and chemical condi tionsnecessary to li fe , as individual sp ecie s flouri sh under those specificcondi tion s which favour them , and fal l to the bo ttom in a dormantstate so soon as those condition s are absent . On the other part ,the ocean currents convey oceanic organisms from adj acent portionsof the North Atlantic . The fate of these organ isms is too , both inthe ocean and the coast
,entirely dependent on hydrographical changes .
Thei r occurence on the coast i s thus dependent,partly
,on the
hydrographical condition of the eastern branch of the Gulf Stream ,
and partly,on the condi tion s present on the coast i tsel f.
As all the inflow ing bodies of oceanic water are of an Atlantickind , the Arctic organisms , which may be met with at certain times ,must
,in any case , pass through Atlantic water i f they real ly are
der ived from the Arctic current,but their subsequent appearance
,
in the colder and fresher water on the coast , i s no proof of thecoastal water’ s Arctic origin .
B i b l i o g r a p h y.
96 . A tmn'
tm l'l , C . S. Das Plank ton d er Bat
’
flns bav und Davis S trai t.1896 . F a tah -i]? fo
'
r L ilj ebory.
V ergleichend e th iergeograflsche Unters uchungen uber d ie
Plank tonformen d e s Skagerak s in d en Jahren 18923—1897.
1898. Kong] . Srn wka Vete nskapsakadm i iens H and linqar.
B . 3 0 . no. 3 .
Bmom wnu , Ta . On the Fi lamentous . Longhorned D iatomacew , w i th a
Description ol"
l‘w o N ew Species . 1856 . Q uarterly Jo urnal
of Microscop ical Science. Vol. I l
86 . Ga rm en ts nz om A su nnntnu a . A . F. R eport on the D iatomaceae col
lected by H . M . S . Challenger during the years 1873—76 .
1888 . R eportof the Scientific Results of the Voyage ofH. M .
S. Chall engm'
. Botany. Vol. II.
97. 0mm. CAR L . D ie Bez iehungen z w ischen d em ark tischen und antark tischenPlankton . S tuttgart 1897.
94. P . T. PIank touund ersokn ingar. Bihmvg til konyl . srenska Veten
skapsakademiecs H and lingar. B . 2 0 , A fd . III. no. 2 .
Ven etabilsk Plank ton . Ibidem B . 2 2 ,A fd . II ] . no. 5 .
A Treat ise on the Phy top lank ton of the Northern A t lanticand its Tributaries . 1897.
97. Cm vx, P . T.,Exams . G. . HJORT. J 0m m 0 0 P errnassox . Orro . Skagerakstilstand und er ind evaarend e sild et
‘
i sk eperiod e .
54. m nsxm . Mikrogeologie . 1854.
97. F ULTON , T. W . On the Currents ot‘
the North Sea and their R e lat ion to
F isheries . 1897. F ifteenth A nnual R eport of the F ishery
Board for Scotland Being for the Y ear 1896 .
GR AN , H . H. Protuphyta : D iatomaceae. Cilioflagellata 0 0 Silicoflagellata .
1897. D en norske Nor-dimrue- Expedition . 1876—78 .
Bacillariaceen ans d ein kle inen Karajak tfiord . 1897. Biblio
theIi‘a botanica H eft. 42 .
Bemerkungen nber d as Plank ton d es Ark tischen Meeres .
1897. Berichte tierD cutschen Botmiischen Gesellschaft. B . X V.
84. a ow , A . Die D iatom ean von Fran z Josephs Land . 1884. D enkschriflen
d . kaiser] A lmd . d . lViss. Jfath. Cl . B . 48.
90 . Hi m n, ERN ST. Plank ton - S tud ien . Jena 1890 .
87. Hm sxx, V . Ueber d ie Best immung fi es Planktons od er d es im Meeretre ibend en Materials an Pflan z en und Thieren . 1887. F iinfter
Bericht (Icr Kommission z ur Untersuclnmg der deutschen lifeere.
95 . HJon'r Jom . Hyd rografisk - biologisk e stud i er over norske fisk erier. 1895.
U nd ersegelser over organiem erne 0g strom forhold ene i d etnorske N ordhav . Naturen
64. LAUDZ B. R emarks on the Marine Diatomacea found at Hongkong , w i thDescript ions of new Spec ies . 1864. Transactions of the
Micr . Soc. Lond . N . S . Vol. XII.
96 . L AOTBRBOBN , R . Ueber (last Vorkom inen d er Diatomeen -Gattungen A ttheyaund Rhiz oaolm ia in d en A ltw assern d es Oberrheins. 1896 .
Berichte d . deutsche n baton -Escher: Gesellschaft. B . XI V.
68. Leann ,J. R . t sikal ische Verha ltniuse und V ertheilung d er Organismen
im Q uartierischen Golfe . W ien 1868.
98. Mz unn nntm, W . Ueber einige meteorologische Bez iehungen z w ischen d em
N ordatlantischen Ocean and Europa im Winterhalbjahr . 1898.
Meteorologische Zeilschri/t. B . XV, H. 3 .
87. Moan. H . N ordhav ets Dybd er, Temperatnr og Stromninger. 1887. Den
norske N ordlmve-E zpedition 1876—78.
88.
93 .
96 .
91 .
96 .
MURR A Y , G. R eport of Observations on Plant. P lank ton . 1897. F iftee nthA nnua l Report of the F ishery Board for Scotland , Part III .
MURR A Y . J. On the E fl ects of Wind s on the D istribu tion of Temperaturein the Sea and Fresh -water Lochs of the Wes t of Scotland .
1888. The Scottish Geographical ill agaz ine.
Summary of the Conten ts . R eportof the Scientific R esults ofthe Voyage of H . M. S . Challenger.
PETER SEN C . G . Jon . D et videnskabelige ud hy tte at kanonbaad en“Hauch”
s
togter i d e d anske have intlent‘or Skagen i aarene 1883—86 .
Planktonstud ier i L im fjord en . 1898. Beretning til Indenrige
ministcm'
et fra D e n danshe biologiske Station . VII .
PRT’I‘ERBSON , O. Ueber d ie Bez iehungen z w i schen hydrocraphischen und
meteorolog ischen Phiinomenen . 1896 . Ill eteorologische Zeit
schrift. B . XIII .
PET'I’ER SSON . O. and E KMA N
, G . Grund drag en af Skagerack s och Kattegats
H ydrografi. 1891 . Ko ngl . Svenska Vetenskaps . A lcademiens
H andlingar . B,24
,no. 1 1 .
De hydrografiska t'
orandringar ind om N ot‘d sJons och Os ter
sjiins Omraad e und er tid en 1893—97. 1897. Ibidem . B .
2 9, no. 5 .
Die hyd rograph ischen V erhaltniase d er oberen Was-er
sch ich ten (l ea n iird lichen Nordmeeres z w ischen Sp i t z bergen ,Gron land und d er norweg ischen Kiiste in d en Jahren 1896
und 1897. 1898. Bihang til k . s-
venska Vetenskaps - A kade .
mim e H andl'ing‘
r. B . 23 . A fd . I,no. 4 .
R ORDAM K . D e hyd rografisk e. F o l-hold i d e d anshe F arv and e ind ent‘or
Skagen i 1891—93 . 1896 . Beretning fra Kommissionen for
tidenskabelig Umlersooelse af dons/cc F arvande. B . I .
96—97. Bo'rma, R . Isforhold ene i farv and ene Get for Gron land 0 g i Dav is
79.
97.
88.
93 .
96 .
80 .
97.
straedet sam t H av ets Overflad etemperatur i d et nord l igeA tlanterhav 0 g Dav isstraed et 1896 . ll/Ieteorologisk A arbog
1 896 III . 1897. D etdanske meteorologiske Iiwtituts nautisk
meteorologiske Obsw vationcr 1897.
R Y DER,C . Den ostgron land sk e Exped i tion 1891 92 . Hyd rogra fiak e Do
d ersegelser. 1895 . hfeddelelser 0m Gronla-nd X VII .
Isforho ld ene i lg‘
nrv and ene Get for Gronland 0 g i Dav isStraedet 1895. Meteorologisk A arbog 1 895, T. III .
Isforhold ene i N ordhav et 1877—99. Tidsskrift for Soccese n
1 896 .
Su e, G . O. Indberetninger til Departementet for d et Ind re om d e l
A arene 1 864—78 anstilled e Und ersiigelser angaaend e Saltv and sfiskerierne .
SCHR ODER , B . A ttheya, Rhiz osolem'
a und and ere Planktonorgauismen im
Teiche d es botan ischen Gartens z u Breslau . 1897. Berichte
der deutschen botanische n Gesellschaft. B . X V.
Scmrr'r,Fr. Ueber d ie Gat tung Chw toceros . Botanische Z eitung 1888.
Das Pfianz enleben d er Hochsee . K iel u. Leip z ig. 1893 .
STBODTMAN N , S. P lank tonuutersuchungen in holste inischen un d meck len
burgischen Seen . 1896 . F orschungebericht ans der biolo
gischen Station eu Plan . Th. 4.
Tow on, H. Chemi. 1880 . D en norske Nordhavserp editwn 1 876 78.
“ m om s , E . Die F auna und Flora Gronland s . 1897. Gro'
nlands -Expe
dition tier Gesellechafl fitr Erdkunde z u Berlin 1891—93 .
B . II . 1 Theil .
A . Summer time .
1. Sections off the Norwegian coast June and July 1895.
S ec tion ofi‘
S tavang er.ete uly0 20 20 17 36 3 1 41 30 2 8. n
5 2 00 17 68 32 00 3 1
10 1 50 17 74 32 09 3 1
1 5 9 60 18 83 34 05 33
18 9 70 18 83 34 05 33
20 9 80 19 22 34 75 33
30 5 60
40 5 40 19 62 35 47 34
60 5 80 19 93 36 02 35
80 6 20 19 93 36 02 35
20 5 70 20 08 36 24 35
60 5 80 20 08 36 24 35
0 2 60 17 68 32 00 3 1
5 2 20 17 75 32 1 1 3 1
10 1 50 18 30 33 10 32
15 8 80 18 64 33 71 32
20 6 60 18 96 34 29 33
40 6 19 38 5 03 34
60 5 19 67 5 56 34
80 6 20 03 6 1 7 35
20 6 20 08 6 24 35
00 6 20 08 6 24 35
80 5 20 08 6 24 35
0 1 1 16 91 0 60 29
10 12 16 91 0 6 0 29
15 1 1 17 00 0 77 30
20 1 1 17 10 0 94 30
30 1 1 17 68 2 00 3 1
40 9 18 6 5 3 08 32
60 7 19 43 5 12 34
80
20
00
60
Sec t ion ofi’ Mars ten en b eacon near B ergen .
0°
402'
a .m . 0 19 o 4 34
10 19 o 4 34
N1
S ection ofi‘
Ch ris tian ss un d .
Meter0
10
20
30
60
80
1 20
200
300
0
1 0
20
30
40
60
80
1 20
200
300
0
1 0
20
30
40
60
0
10
20
30
40
60
80
120
6 ) S ection ofi‘
V igten .
64042’
90 8‘5
1 00 90
1 0
H
b—l
Gi
dfi
dt
kl
fl
fl
Q
CO
C
r—flmaflq
ot
oz
owo
P—‘b—dcr
e
a
me
r
i—tr—aOi
w
ci
ul
ct
w
c
h‘
95
46
96
00
16
50
29
1 2
88
20
85
05
25
75
48
40
86
72
70
55
95
35
85
92
56
95
10
20
20
80
60
70
95
Section ofl’
Bod o—B os t (continued ) .
pan .
12 nl id n.
3 a .m .
II. Observations from Nordland
Ob ser vations from L ofoten .
1 Dieter
O
10
20
30
40
60
80
120
200
1) Hula in Lofo ten .
2) H e lligw er.
12
12
10
8
7
ti
6
6
6
80
50
40
80
70
60
30
15
00
Saline contents
3am a we
19 93 16 0 1 1
19 89 15 95 0
19 93 1
3 3 08
19 39 35 0 3 18
19 6 4 35 5 3 62
19 80 35 7 21 88
19 88 35 9 11 0 1
20 0 1 36 1 3 23
20 0 1 3 1 6 9 23
20 09 3 6 2 3 216
20 19 36 4 3 50d
N)
kl
3) Stensv ze r.
4) Vestfjord en .
S ection Ofi’
Bod o—R ost (cont inued ) .kl e te
10
20 7 75
3111 ii ( 111
40 5 10
60 4 52
80 4 60
120 4 90
200 5 30
811111 11101“
44
47
48
49
01
o:
8;
on
\I
1 3
13
13
13
13
13
14
14
14
14
14
14
14
10
12 m .d .
p 111
p .m .
I p.m .
1 1 p m
2 45 a m
an
7 30 a m
9 30 a m
1 1 a m
12 30 p m
10
20
40 43
31
31
01
40
00
20
40
20
20
I Sal ine contents
19 50 35 25 34 36
19 80 35 79 34 88
19 80 35 79 34 88
19 80 35 34 88
c
14
14
15
7 p m
9 p m
2 a m
2 a m
a m
30 a m
1 a m
1 30 p m
2 p m
30 a m
Observations June 1896,H . M . S.
“R anst-een ”
S ection
a .m .
0 ) S ection ofi‘
P raiau .
8
8
19 89 85 96 35 04
S ec tion H ustad v ik en—Storeggen .
64"
S ection 0 11” Hal ten b eacon .
64° 5
H ustad v ik en—Storeggen (cont inued ) .Mete60
80
100
1 50
200
250
290
0
20
40
60
80
100
15 0
2 18
245
0
20
40
60
80
100
1 15
sqxi
q
q
q
q
co
q
q
q
q
q
q
oo
xl
fl
fil
xl
ct
fl
fifi
.
oOOl
.95
.96
.85
.51
.22
.1 7
.01
.32
.32
.20
.52
.80
.71
.50
.42
.30
.20
.92
.23
.69
.60V 7
.0 0
19 93
20 0 1
20 01
20 01
20
20 0 1
20 0 1
1 9 06
1 9 29
19 71
19 95
20 0 ]
20 01
19 06
19 29
1 9 47
19 89
20 0 1
20 01
20 0 1
36 O3
36 16
36 1 6
36 1 6
36 1 6
36 16
36 16
34 46
34 88
35 62
36 05
36 16
36 16‘
34 46
34 88
39 19
35 96
36 1 6
36 1 6
36 1 6
35 1 1
35 23
35 23
35 23
35 23
35 23
35 23
33 63
34 01
34 71
35 13
35 23
d ) Sec tion 0 8 Hal ten beacon (continued ) .
p.m .
9) Sec tion o u t ofl’Sognetjord .
3° 6'
Meter100
150
20 0
250
30 0
380
0
20
40
60
80
100
150
220
~1
~l
kl
sl
fl
u
q
al-l
fl
w
o
.42
. 12
.52
.05
.05
.75
.42
.62
.25
.00
.98
.05
.0 0
a) Section Sognefiord—Icelan d .
a.m .
19 95
20 0 1
20 0 1
20 0 1
19 53
19 89
19 89
19 89
19 89
20 0 1
20 0 1
1991
36 05
36 16
36 16‘
35 30
35 96
35 96
36 16
36 16
35 99
35 13
35 23
34 40
35 04
35 04
35 23
35 23
June
H . M . S.
“He imd al ”V. Section Sognefjord—Iceland May 1897,
a) S ectio n Sognefiord—Iceland (cont inued ) .p m
4 p m
p m
12 a m
4 a 111
atm
l p m
7 p m
Il a/4 p m
0 19 74. 35 59 34 77
0 19 63 35 5 1 34 6 1
0 0 0 0 19 59 35 42 34 59
S ection out ofl’Sognefjord (cont inued ) .
Meter40
60
80
10 0
150
200
250
300
370
0
20
40
60
80
100
150
200
250
300
330
365
100
9
12
10
. 18
.30
. 14
.70
.30
.85
.48
.72
.40
020
.26
.72
9 .45
oz
q
oo
q
oo
oo
co
.20
.73
.1 5
.60
. 10
.90
.50
20 0 1
19 91
20 1 1
20 02
19 98
19 99
19 94
19 91
19 94
19 34
19 94
90 1 1
20 04
20 08
20 06
20 08
20 02
98
19 99
20 03
19 88
36 16
3 6 15
36 20
36 I6
36 10 2 .
36 I5
36 04
35 99
36 04
34 96
36 04
36 29
36 19
3 6 21
36 22
36 24
36 16
36 10
36 15
36 17
35 93
35
35
35
35
35
35
35
35
34
35
35
35
35
35
35
35
35
35
35
a) S ection Sognefiord—Iceland (cont inued ) .Mete
0 35 32 34 42
1 0 0 20 35 32 34 42
20 0 20 35 32 34 42
50 0 00 35 32 34 42
80 0 00 35 32 34 42
1 20 0 20 35 65 34 76
200 0 30 35 6 1 34 69
300 0 30 35 6 1 34 69
0 50 35 2 1 34 33
35 25 34 36
0 20 35 25 3 4 36
0 20 35 2 1 34 33
35 29 34 40
35 6 1 34 69
35 42 34 53
1 1 Surface observations May and September 1896,mad e by Cap t . H . A N DR ESEN , Trom so
fl)
ay ay
139 14 8 p .m . 0 40 19 19 34 72 33 86 1 0 1 6 4 p 0 3° 40 19 64 35
140 14 1 2 m id n . 0 4 1 9 26 34 84 33 98
1 1 16 m id n 0 0 00 19 36 35 02
4 a m 0 5 19 57 35 39 34 50
1 2 1 O 0 40 19 29 34 90h a m 0 5 60 19 70 3 5 62 34 72
9 a m 5 so 19 81 35 82 34 9 1[ 9 43 3" 14
0 2 60 18 92 34 23
144 noon 0 5 60 19 81 35 82 34 91
145 5 50 19 3 1 35 9 34 91 1 5 1 4 p m 0 5 20 19 64 35 52
146 0 5 40 19 81 35 82 34 91 1 6 1 8 p m 0 5 20 19 67 35 5"
147 2 m id 5 40 19 81 35 82 34 91 1 7 1 4 a m 0 4 80 19 50 35 27
148 4 a .m 0 4 40 1 8 1 8 a m 0 5 00 19 64 35 52
149 8 e .m 0 4 40 19 81 35 82 1 9 1 10 a m 0 5 60 74 35 70
1) D istances in geografical m iles .
34
34
34
33
34
34
34
34
a) S ection Sognefiord—Iceland (continued ) .Me ter20
50
80
120
200
300
0 .00
0 .30
0 .10
0 .00
0 .40
19 59 35 42
1 9 59 35 42
19 59 35 42
19 59 35 42
19 59 35 42
19 59 35 42
Icelan d—F eie b eacon , s u rface ob servation s .67° 0
’
1 0° 5’W
34 53
34 53
34 53
34 53
34 53
34 53
181 p .m.
O
0 a m 0
0 9 .00
0 9 .40
O 8 .60
0 9 .40
0 0 .20
4 a m 0 9 .80
O 9 .60
8 . W inter time
Sections off the Norwegian West coast February—March 1896,
taken by 0 . N ORDGAA BD .
a) S ection ofi’Stavang er (continued ) .
41- 5} p m 0
5 5 .71
10 5 .71
I5 5 .71
20 5 .81
30 5 .90
40 6 .50
60 6 .95
80 7 .2 1
100 7 .20
b) S ection ofi'
Marstenen b eacon .
0° 9‘
5 6 p m 5° 4‘
1 5 1 1 12 51 111
19
19
19
19
19
19
19
18
\l
\l
\l
35 62
35 57
03O‘
3!
ul
34 37
34 67
3 1 72
34 67
34 67
34 67
34 67
33 51
b ) S ection 0 13?Marsten en
Febr. 60° 7’ Meter
185 1 5 2—3 a. m 0
10 5 .70
20 5 .85
30 6 . 15
40 6 .20
60 6 .45
80 7 .1 7
1 20 7 .35
150 7 .20
Ch ristian ssun d .
Me ter22 104- 11} a.m. 0
1 0 5 .60
20 5 .80
30 5 .81
40 5 .76
60 5 .87
80 6 .1 5
1 20 6 .55
1 50 7 .07
200 7 . 15
7 . 1 0
1 2 1 - 1 a .m . 0 5 .60
10 5 .65
20 5 .57
3 0 5 .60
40 5 .6 1
60 5 .77
80 5 .85
100 5 .85
120 5 .83
22 2315
- 3 p .m 0 4 .60
10 4 .65
20 5
30 5 . 1 5
40 5 .25
60 5 .70
80 5 .85
10 0 5 .85
120 5 .83
28 12—1 p .m .
28 2 % 34p .m .
28 4g 5 p
b eacon (con tinued ) .
"0
19 36
19 36
19 36
19 42
19 42
19 54
19 78
19 90
1 9 96
19 45
19 45
19 5 1
19 51
1 9 51
19 60
19 63
19 69
19 80
19 83
19 94
19 38
19 38
19 41
19 45
19 45
19 51
19 5 1
19 51
19 51
18 74
18 74
18 92
19 09
19 09
19 33
19 5 1
19 5 1
19 57
19 39
35 00
35 00
35 00
35 10
35 1 0
35 32
35 75
35 98
36 07
35 1 6
35 1 6
35 28
35 28
35 28
35 42
35 51
35 60
35 79
35 85
3 6 04
35 03
35 03
35 08
35 16
35 1 6
35 28
35 28
35 28
35 28
33 88
33 88
34 23
34 5 1
34 51
34 94
35 28
35 28
35 38
1 9 57
34 1 3
34 1 3
34 13
34 23
34 23
34 42
34 84
35 05
35 15
34 28
34 28
34 38
34 38
34 38
34 53
34 6 1
34 70
34 88
34 93
35 12
34 16
34 16
34 2 1
34 28
34 28
34 38
34 38
34 38
34 38
33 06
33 06
33 38
33 66
33 66
34 07
34 38
34 38
34 50
18 98 34 32 33 48
19 04 34 42 33 58
d ) S ection of V igten (con tinued ) .Meter60
80 5 .8
1 20 6 .5-5
March1 3 9 94
1 3 1 2—1 a .m .
1 3 24- 3% p .m .
1 3
14 645
- 7 a .m .
1 4 94- 10 a .m .
198
March14
10
10
10
10
14
14
14
14
14
up 5
Meter0
10
20
30
40
60
Observations from Lofoten.
0
e Section 0 3 Lofo ten (continued ).
19 14
19 15
8 .47 19 15
1 9 15
19 15
19 27
18
18
18
18
3 .60 19
8 .40 18
3 .40 18
84 62
34 62
34 62
34 62
34 62
34 83
taken
samp l es ob tained on the line H el ligvmr—Sv olv eer.
1 p .m .
3 p .m .
4 p .m .
5 p.m .
te
0 1
1
1
1
1
1 0
33 78
33 78
33 78
83 78
83 78
33 97
by O. N onneu m) .
38 15
33 15
33 85
33 29
33 58
33 48
33 48
Mete80
120
150
200
250
March—April 1896.
ete
e) S ection of L ofo ten (cont inued ) .
5 .70
6 .10
6 .45
b .57
1
5 16 34
5 38 34
5 60 84
6 03 35
49
~
l
9
63
64
March
10
10
10
10
1 1
1 1
1 1
8
12 noon
4 p.m
8 p .m
4 mm .
6 p .m .
10 p .m
24 am
6i a m
1 p .m .
12 noon
4} p .m .
U tsire—Icelan d (continued ) .
b ) Iceland (Mal ey re).
ete
0
0
0
5
10
O
O
0
c) Iceland—Hammerfest.
Ma r
‘1
s]
lo
is
C
O
x!
!oO
‘
10
ino
O _
o
0
0
0
0
0
0
0
0
0
0
0
01
0
0
C
50
60
80
80
19 39
19 46
19 3 1
19 35
1 9 41
19 38
1940
19 37
19 6 1
19 62“
19 64
19 64
19 65
3 6 10
36 03
36 03
35 96
36 05
36 04
36 08
35 66
36 08
36 03
34 89
35 32
35 04
35 1 6
34 91
34 98
35 08
35 03
35 06
35 0 1
35 52
35 53
35 1
35 1
35 1
35 1
35 1
35 0
35 1
35 1
35 1
35 1
35 1
34 3
34 0
34 4
34 18
34 30
34 04
34 12
34 2 1
34 1 6
34 20
34 14
34 54
34 56
34 62
34 62
34 63
68
x]
01
76
77
79
80
81
82
83
10
10
10
10
10
1 0
1 1
1 1
1 1
1 1
1 1
1 1
1 2
12
c Ioeland—Hamm erfes t (con tinued ) .Me ter Meter
9 0 19 62 35 47 34
1 p .m . 0 19 68 35 58 34
5 p .m . 0 19 53 35 30 34
7 p .m
121 am
5 a m . 0 19 36 35 00 34
8
1 p .m
54 p .m . 0 1 .20 1940 35 06 34
74 p .m
12 2} a m
44 a .m . 0 19 73 35 66 34
8 a.m
1 p .m .
6 p .m . 0 1 9 94 36 04 35
1 1 p .m . 0 19 92 36 0 1 35
5 a.m . O 19 98 36 10 35
1 2} p .m 0 1998 36 10 35
63, p .m . 0 19 86 35 89 34
1 3
1 3
13
1 3
14
14
14
14
e Icelan d—Hamm erfest (cont inued ) .
0
44,
o
9 0
4 0
Q 0
9 0
39 0
4 .65
1 9 93
1991
19 89
19 90
19 93
19 89
19 96
36 03
35 99
35 96
35 98
36 03
35 96
36 07
1 3
35 10
35 07
35 04
35 05
35 1 0
35 04
35 15
296
297
300
30 1
A pl'i
14
15
c) Icelan d—Hammerfest (con tinued ) .
I) urfd ee observations in the Norwegian
February—March 1897.
U t sire—A rc tic Ocean , S /S ”Westye Egeberg Capt . TUF TE .
to
0
0
C
C
O
O
O
O
C
O
O
C
3 o
5
6
1 8 81
19 73
1 9 39
19 50
19 34
19 26
19 89
19 26
19 81 '
34 0 1
35 66
35 60
36 02
36 02
36 05
3 5 96
35 96
35 91
35 89
33 19
34 73
34 70
34 36
34 10
33 95
35 04
33 95
34 89
34 73
34 36
34 73
35 10
35 10
35 1 3
35 04
35 04
35 00
34 97
a) U t sire—A rc t ic Ocean ,
3 1
TC
8
8
O
C
QD
QC
CC
CD
o
00
ml
.\
A
War
MeteO
10 5 .10
20 5 .00
50 5 .1 0
100 5 .1 5
200 5 .30
0 4 .1 0
0 2 .00
in North
19 65
19 6 1
19 67
1 9 68
19 75
19 78
19 51
35 53
35 45
35 56
35 58
35 71
35 75
35 28
34
34
34
34
34
34
19 52 35 29 34
1 9 52 35 29 34
S/S VVestye Egeberg Cap t . TUF TE (con tinued ) .
63°58'
N .
64 8’
2 23'
64 23'
2 26’
34 38‘
2 24'
64 53'
o 90 1
65 8‘
2 17’
65 24'
2 12'
65 40‘
te
0
O
O
C
C
O
O
O
C
O
O
C
O
O
O
C
O
O
O
5
41/
5
19 87
19 82
1985
19 84
19 90
19 89
19 90
19 89
1 9 89
19 89
19 93
1 9 89
19 89
19 89
19 91
19 89
19 85
19 89
19 89
35 91
35 85
35 88
35 86
35 98
35 96
35 98
35 96
35 96
35 96
36 O2
35 96
35 96
35 96
35 99
35 96
35 88
35 96
35 96
35 00
34 92
34 96
34 94
35 05
35 04
35 05
35 O4
35 04
35 04
35 10
35 04
35 04
35 04
35 07
35 04
34 96
35 04
35 04
U ts ire—A rctic Ocean , 8 S "Westye Egeberg“
, Capt . Turn; (con tinued ) .Are}
10
10
10
10
10
10
10
10
1 1
l l
1 1
l l
1 1
1 1
1 1
l l
8
10}
01 pm
2} p.m .
6 } p .m.
7} p .m .
10} p .m .
1
31 a.m .
61} a .m .
9} a.m .
p .m .
8 p .m .
6 p .m .
1 1 p .m .
b ) Utsire—A rctic Ocean ,
3!
p .m .
1 ) Ice .2) Ice .
te
0
0
0
0
O
Sm ousnn.
Capt. O.
”Prospero“
.
l 70‘W
55 29‘
0 41‘‘V
55 45‘
O15’ W
56 1‘
0 1 1' E .
56 18’
0 38' E .
56 34‘
1 60‘
56 48’
1 29‘
57 10‘
l 50‘
57 16’
2 1 5’
57 30‘
2 40’
57 45‘
3
57 59'
3 32'
58 14'
3 56’
58 28‘
4 22‘
58 42’
4 48
59 0
5 17'
d ) Christianssaud—N ew castl e , S/Ste
4 p .m . O
1 5
Christianssaud—N ew cas tl e , e) Christianssaud—A n tw erp en ,
4 p .m .
2
4 a .m .
e) Christianssaud—A ntw erp en , S/S "Odin“
te
0 'oc 33 45 32 65
0 33 82 33 00
O 34 65 33 79
35 66 34 75
34 69 33 84
35 38 34 50
8
8
8
8
8
8
6 a.m . 35 53 34 63
35 38 34 508 a .m .
35 06 34 20
8
8
35 2 1 34 33
8 35 19 34 32
.00 35 38 34 50
.50 35 38 34 50
.50 35 38 34 50
.00 35 30 34 40
.50 35 14 34 27
c
o
o
o
o
o
o
o
c
fi
h
a
m
w
m
m
m
w
w
w
w
w
h
w
w
tg
'oo
O
O
O
O
O
.50 35 38 34 50
Observations from Lofoten February—April 1897.(0 . N OR DGA ABD ) .
f ) A ntw erp en~ Christians saud , S/S ”Odin
te
0
©
0
0
0
0 5 .50
.50Cl
.50O‘
Ct
.50
O!
.00
10
65
L erfjord 25
(He lge .
land )
A t Stii t,
(K arma)
Them outhof the Sal
ten fjord
0
50
100
0
50
0
10
50
0 0
10
0
OD
CJ
CE
OQ
p.
oc
oo
v-fl
w
a
s:
00
03
03
[0
10
10
10
80
80
20
50
1 0
10
10
10
80
10
20
50
80
80
70
70
19 05
19 09
19 0 1
19 01
19 01
19 12
19 12
19 1 2
19 09
19 12
18 72
19 12
19 12
19 1 2
19 22
34 59
34 47
34 54
34 40
34 40
34 40
34 59
34 59
34 59
34 54
34 59
33 87
34 59
34 59
34 59
34 77
34 96
33 73
33 73
33 73
33 6 1
33 68
33 54
33 54
33 54
33 73
33 73
33 73
33 68
33 73
33 04
33 73
33 73
33 73
33 91
1 7
A t Groto
Hola
10
“
My
.10
30
231 )
30
30
3 1
\1
VI.
6 p .m .
8 p .m .
10 p .m .
12 m idn.
2 zu n .
4 mm .
6 mm .
8
N.
)
4 p.m .
6 p .m .
8 p .m .
10 p .m .
12 m idn .
12 m idn.
2 a .m .
12 noon
2 p .m .
Surface observations in the North Sea 1896,
8
.60N1
st
10c:
8
mad e by Capt . Tnovssx S,‘
S MercurB erg en—N ewcastl e .
9
1 7
28
IOa
.
10 O!
10 \
1
6
10
6
6
8
p .m .
!l ‘ ln '
p .m .
p .m .
midn
aO ln .
10 a m .
4
6
p .m .
Meter0
0 5 .90
1 9 83 35 85
19 58 35 4-1
2 su n .
4 mm .
ti mm .
8
10 tu n .
0 0 0 “
8 p .m .
1 0 p .m .
4
8 su n .
9 .40
0 7 .00
0 6 .40
0 6 .40
Sal ine contents
18 84 34 09 33 25
19 12 34 59 33 73
19 08 34 54 33 68
s 44 :
_ §L_ 53
11 111
1)
8
12 m id n .
2
to P S
4
12 noon
2 p .m .
Salt Sal tper per
li tre l i tre im i llo
NOTES.
The sample s were gathered by means of small bags of fine canvas (No . 16 or These were ei ther towed along near the
surface of the water , or sunk to a certain depth , for instance 50 metres , and hauled straight up . The given temperature and sal ini ty ,
in the latter ins tance refers to that at the greatest depth reached by the bag . The occurrence of the various Plankton Organi sms is
represented by the follow ing symbol s .
C C
PLATE 1.
Chart of the Depths of the Northern Ocean . (MOHN : The northern Ocean , Its Depths , Temperature and Circulation , P] . H ) .
Bergens Museums Plate 1 .
Lith.Aust. .Julius Klinkha rdtl eipz ig
PLAT
Chart of the Northern Ocean , shewing the Sal in ity and Temperature on the surface during the Summers 1876 compi led
from TORNOES and Moun’
s charts in the Report of the Norwegian Northern Ocean Expedition , suppl emented by the resul ts der i ved
from the Drache Exped i ti on .
The Isotherms are p ri nted in red .
Chart of the Northern Ocean, shewing the temperature and sal in i ty on the surface during March and Apri l 1 897.
The Isotherms are p ri nted in red.
The bl ack l ines indicate the routes on whi ch observations were made . The Surface Observations are denoted by cross l ines,
the Deep Sea Sounding Stations are indicated by smal l circle s .
See al so the Hydrographical Tables B, III—IV, pp . 1 1 —1 5.
PLAT
Bergens Museums Plate 3 .
Lith.Anst.Jul ius fl inkhardt,Leipz ig.
PLATE 4 .
Section Sogne F jord (61 0 9'
5" N . Lat ,
3 ° 50'
5" E . Long .) Iceland (66° 32
' N . Lat , 70 1 5
'
“7. Long ) , May 1 896 .
The Sal in ity of the variou s layers i s given in the same col ours as on Pls . 1—2 .
The I sotherms and Temperature are p rinted in red l ine s and figures . The coloured doubl e columns under indivi dual Stations
rep resent the occurence of Plankton Organisms . The indiv idual Species are pri nted to the l eft of the hori zontal l ines ; the
Oceanic Sp ec i es be ing denoted by Blue colouring, the Neritic by Red (Southern or Summer Forms) ; Brown representing the
Northern or \Vinter Forms,and G reen th e Arctic Forms .
The comparative frequency is given i n var ious tones of colouring , the l ight tints indicating that the species occurs in fewnumbers
,the darker denoting a pl en tiful appearance .
See Hydrographical Tabl e A,III
,and Plankton Tabl e 2 .
This rep resents the same Secti on in May 1 897. Hydrographical Table A ,V. , Plankton Tabl e 4 .
strob e eiooiw mo : acm ftiswii
Good naiocuo cm nh icm
a kim olm io 0 6 mm
3mm .
cin am
W M b ngdooim a
g im ph tj-eio a cu te.
m . lo ngi'
pco
Hjor‘t' Gran del
PLATE 5 .
1 . Section , Uts i re—Iceland , March 1897. Thi s Section i s del ineated on the Surface Chart,Pl . 3 .
See Hydrog. Tab . B . 111 .
Secti on off Hustad viken near Christianssund . The Isotherms are printed in black .
Se e Hydrog. Tab . A . IV, Sts . 77—80 .
Graphic representation of the variations o f Temperature at var iou s depths during each month of the year off the West Coast
of Norway .
Similar representation of the different degrees of Sal in ity down in the deep throughout the same p eriod at the same place .
The col ours have the same significati on as those on P ls . 2 - 4.
1—4 .
1 a .
1 5.
2 a,5.
3 a , 6.
4 a, b.
PLA E
Sections off the Norwegian Co ast in Summer and \Vinter .
Ofi'
H vidingsij , near Stavanger, Summer . Hydrog. Tab . A . I,Sts . 1 3 .
The same local i ty during Winter . Hydrog. Tab . B . I,Sts . 1 79—182 .
0 3“
Marstenen ,near Bergen . Hydrog. Tabs . A . I
,Sts . 4—6
,and B . I
,Sts . 183 185.
Off Chri sti an ssund . Hydrog. Tabs . A . I,Sts . 7—1 0 , and B . I
,Sts . 186—1 88.
0 11 Vigten . Hyd rog. Tabs . A . I,Sts . 1 1—13 and B . I
,Sts . 1 89
See Hydrog. Tab . A . IV, Sts . 8 1—83 .
Bergens Museums SkrifierNoLVl .
Veetem afoeggew .
Stl .
3'l . 22 .
3't. 38 . 18 . 15 . B'i
b?! “1 M ia/ 1896
PU
CON TEN TS.
General Remarks on the Lofoten Fi she ri es .
Hydrographi cal Inves tigations
Biological Investigation s
a) Observations concern ing fish es , especial ly cod (gadus ca llarius , Linn .)
b) Notes on ce rtain plancton forms
Final Remarks
A. General Remarks on the Lofoten F isheries.
many centu ri es No rwegi ans have gone to the Lofoten i slandsorder to fish cod . At several places in the old sagas
accounts are found showing that the winter fisheries have been ofgreat importance during al l the time that Norway has existed as aun ited kingdom . In the past
,as wel l as at present , the cod fishery
of Lofoten has given a certain harvest every year,though the
amount of the catch has vari ed very much . The fact that theLofoten has from ancient times been known as the place wheremen could most surely harvest from the ri che s of the sea, canprobably be adduced to a plural ity of circumstances . The Lofotenfishery is a “
gaabfishery”
,i . e . the arrival of the ocean cod
within reach of the several catching gear (sink - l i ne,set- l ine , nets ,
&c.) i s o riginated by the powerful impul se of propagation , which ,supported by a remarkable instinct , causes l arge masses of sexuallyripe indiv idual s of cod to move in upon the coast banks . Therei s certainly reason to think that during the spawning time the coddoes not deny its nature and despises the claims of its stomach
,
but stil l the real thing seems to be that during the spawning timethe feeding questi on becomes one of secondary importance . Iti s al so wel l known that the F inmarken “ lodde -fishery
” i s morevariabl e than the Lofoten fishery , a fact evidently caused by theci rcumstance that the migration of the cod shoal s in the latter casedepends on the presence of the “ l odde ” (ma llotus v i llosus) . Thechi ef cause of the favourabl e re sults of the long - establ ished Lofot enfisheri e s is certainly to be looked for in the construction of theocean bottom . By the soundings of the government chartographersand of the Norwegian North - Ocean Exped ition
,a good survey has
been obtained of the bottom of the ocean ; thu s the existence hasbeen proved of considerable bank plateaux outside th e chi ef districtsfor the cod fisheri e s. Especially that of Lofoten i s su rrounded byvast banks
,which the North - Ocean Expedition could follow al l the
way up to Spitsbergen . The circum stance that the water has amotion that makes it wash against the edge of the banks and thuscauses a stowing up of the planctonic food material , i s most p robably an essential condi ti on for the rich development of benthosfo rms of which the above mentioned Norwegian expedition has
gi ven sufficient evidence . Prof. Sans says in the report of theexpedi tion of 1877 : “Outside the district of Aalesund stretches
the bank - edge Storeggen , already known and used for bank fishingin older days ; outside the Lofoten district howev er l i es , as we havebeen abl e to show , an edge of perfectly l ike condition . But in thesame relation , in which the Lofoten fisheries surp ass the
,
Aalesund fisheries in importance , i n the same relation the now di scovered Lofoten edge has an extent as much l arger than that ofStoreggen . On thi s extensiv e edge
,which stretches along the whol e
of the long isl and group of Lofoten and further northward,as w el l
as in the coast sea lying inside of it,there i s no lack of room
even for such enormous masses of fish as those appearing duringthe Lofoten winter fisheri es . ”
There are many reason s to bel iev e that Mr . SAR S i s right indescribing this edge as the real hunting ground of the ocean cod .
Among other things may be mentioned that the hoe-fish huntersreport that this rapacious preying fish particularly sticks to th eedge menti on ed . It i s another thing that the fishing here canhardly be carri ed on owing to the strong current . That al so codand other bottom fish
,as l ing
,haddock
,torsk
,hal ibut , exi st on
the extensive plateau inside the edge , has been proved by th ebank fishers . For that the “bank- cod
” i s nothing but the Lofoten“skrei
” has been made ev ident by the examin ation s of Mr. Sans.
The reason that the ocean cod in the summer is more sparelycaught by the fishermen
,has probably to be sought in the circum
stance that it then moves more thin ly spread . A crowding- togeth erof the cod may however also occur in the summer time
,viz . under
circumstances when some “aate
”
(food matter) appears in greatquantity . Rich catches of summer cod have thus been made occasionally at Spitsbergen , as far north as the 80 - th degree lat . Mr .SAR S in hi s report for 1878 statest hat the North Ocean Expeditionnear Beeren Eiland fell in wi th large shoal s of cod , which were
gorging in fly- a ate ( limacina he licina) . During that same summerlarge catches were al so made at N o r s k - a e r n e in shallow waters
(1 6—18 fathoms) . Here too the limacina proved to form a mainpart of the contents of the fish- stomach . Such a fishery , however ,must be varying, j ust because it depends on a pl ancton organi smthat i s very irregular in i ts occurrence . In 1 883 the summerfishing at Spitsbergen fai l ed completely
,and since that time scarcely
any trial worth mentioning has been made .
Also in Western Norway there occur during the first monthsof the year arrival s of ripe cod , at l east as far sou th as the reefof Jaederen . The fishing of th e ocean cod coming up to the coasthere, thus coincides as to time and place with the spring herringfisheri es . The last mentioned cod fishery however does not in impo rtance come near to the Lofoten and Sondmore fisherie s . TheLofoten fishery i s by far number one , then fol lows that of Sondmore as no . 2 , and that of the
“Wes t land as no . 3 . Even atplaces ly ing between those mention ed , ocean cod is al so beingfished
,but
,as far as has been hitherto ascertained , the amount of
fish i s not so large as on the Lofoten and Sondmore bank s , al
though for in stance on the Vigten bank s and in the d istrict Vester
aalen—Soroen i t i s by n o means unimportant . In these placeshowever the fishing sometimes fai l s .
On a chart of Norwegian waters showing depth curves of thesea bottom. wi l l be seen that the edge of the ocean banks , inmak ing a considerabl e bend inwards , formally points towards theWest- fj ord ; that thereby the chi ef direction of the movemento f the fish towards the coast i s given , i s considered to be af
firmed by the exp eri ence of many years . It i s therefore notvery likely that the cod l iving along the great edge should , whenthe propagating time approaches , take the direct course on theLofoten ; the fish wil l foll ow the edge as i t runs on , and thatthe stream of fish w i l l then be directed i nto the West- fjord i sthereby given .
Professor Hannaxn“) says about thi s : “ If th e ocean cod ,
w hich we know is a bottom fish , on i ts way to i ts spawning groundshas no other guidance for i ts submarin e navigation than the configuration of the bottom ,
whil e the fi sh i s following a depth sui tablefor i t
,then th e conclusion i s obvious that the Lofoten fisheries
must be annual ly con stant , becau se the present configu ration ofthe bottom has been essentially unchanged during the time knownto hi story .
”
About the chief d irecti on of the inward migrati on of the codthere have , however , prevai l ed different opin ion s .
Thus the renowned German geologist LEOPOLD VON BUCH supposed that the cod entered through the Gimsostrom and the Raftsund . and an older Norwegi an author , amtmand BLOM ,
thoughtthat the w id e chann el be tween Ward and Rest was the greatentrance gate .
Lofo ten 0 g Veateraa len, p . 126 .
It i s well known that no cod fishing worth menti oning takesplace on the continental s ide of the Vestfiord . A reason for thi si s easily found . Between the coast l ine and the edge there i s hereonly an extremely narrow band , and the edge con sequently v eryabruptly sinks towards the bottom of the Vestfjord . In other words
,
the bank plateau i s here so smal l, that it does not afford suitabl efishing grounds . It i s however l ikely too that there are no suchmasses of fi sh along the inner edge as along the Lofoten edgeproper . There i s reason to bel i eve that the greater part of thecod shoals that vi si t Lofoten start from the edge and bank plateausituated to the north of Lofoten
,and these shoal s will
,by fol low i ng
the ocean edge , at la st he directed to the fj ord edge on the insi deof the Lofoten i slands . Thus i t i s but l ittl e probabl e that l argemasses of the fish coming from the north shoul d pass across tothe continental edge of the fjord .
On the other hand the bank plateau to the south of Lofoteni s not of such extent as that to the north
,and can consequently
not support corresponding numbers of fish ; besides , the cod fishingthat takes place on the coast of Helgeland shows that the cod l ivi ngmore to the south choose more southerly ways for mi grating to thecoast banks . In other words , i t i s l ik ely that but a very smallpart of the cod l iving to the south of Lofoten seek northward inorder to perform its Spawning .
The fish that hav e spawned in Lofoten,and escaped the fisher
men there , seem also to return northward . Among other thingsthat go to show this
,i s the circumstance that the late fishing that
occurs (the so- call ed “skraapfiske
”
) i s most successfully carriedon off Vesteraalen (for instance at Gaukvsero) .
It i s however a fortunate fact that the Lofoten fisherie s havebeen rather con stan t. season after season for centuries , which canbe explain ed by a con siderabl e stabi l i ty in the natural rel ationsthat determin e their course . It i s no easy matter to point out theposi t iv e and negative causes and the extent of their op eration
,but
in our searching for cau ses we shal l at lea st find two prominenton es , v iz . the immense su rrounding banks and their great powerof producing food for the fish . The ancient glaci ers have secured
our country , so it i s l es s fit for agriculture ; in return the sameglaciers have , by their contributions to the mak ing of our oceanbanks
,given some compensation for what spoi l th ey have taken
from the land .
The then supervi sing chief, Mr . Jean, maintain s that the in
fluence of the ai r temperature on that of the water ne ither seemsto be very great nor to extend far down . This i s of course to bethu s understood
,that a sink ing of the air temperature for a shorter
time does not cause a corresponding sinking of the temperaturedegree of the water layers . The old asse rtion that the co ld shouldexerci se an unfavourabl e influence on the fishing by l owering thetemperature of the water, i s thus depri ved of any support . Theincorrectness of the assertion must al so be said to be proved byexperi ence .
At that time , however , peopl e began getting a strong beli efin the i nfl uence of the sea temperature on the progress of thefishing . The measurements al ready undertaken had sufficientlyshown that the temperatures in the usual fishing d ep ths wereextremely changing . Experience had also proved that in one casefloating gear (
“ doit- redskab”
) made the best catches , whil e in an
other case bottom gear was most successful . It was therefore anobvious conclusion to attribute these anomal ies to the various tem
peratures of the water strata . I will later on enter upon a closerexamination of thi s question .
The Lofoten report for 1880 contains a complete account ofthe measurements of in sp ector LIE at Lodingen from May to December 1879 (p . 94 It appears from the latte r that thesurface temperature reaches i ts greatest values in the month ofAugust C. The average of the surface temperatures observed during thi s month is C . In Sep tember thesurface temp . remain s between 10° and 1 1 ° with an average of
and the temp . i s sinking from the surface towards the bottom .
In the month of October the sea enters into i ts autumn condi tionwith a temperature maximum below the surface
,and
,at the same
time as thi s in the course of the autumn i s l owered in positi vedegree
,i t i s dep ressed at the greater depths until at l ast
,in
value and situation,i t coincides with the zone that seems untouched
by the changes caused by the seasons . The upper l imi t of,
this
zone may be put at a depth of 1 00 fathoms , or a l i ttl e more .On the basi s of Mr . Lrn
’
s measurements , as wel l as the tem
perature media computed by Mr . Koxx for every hal f month forthe observation station at Lodingen (report of 1880 , p . 1 00
I wi l l shortly sketch the annual changes of the temperature of thewater strata . It will then appear whether later observati on s haveaffirmed the main features of thi s account .
In the four first months of the year the surface i s the seatof the temperature minimum
,but in May the latter i s di splaced to
a few fathoms below the surface . According as the heat of thesun influences the upper layers , thi s min imum becomes more prominent and i s at the same time press ed l ower down .
Thus,accord ing to the observation s mentioned above , the tem
perature average for the first hal f of August i sat O fathoms C.
50
100 (bottom)In the first hal f of Sep tember the temperature medium i s
at O fathoms C.
70 6°. l
1 00
In the course of the autumn the surface i s much cool ed down,
and in October the temperature consequently increases down throughthe layers towards a maximal v alue , and then sink s again . Theautumn max imum has a simi lar movement as the minimum in thespring , i t i s pressed deeper and deeper unti l i t i s lo st or turnsinto the zone that seems untouched by the annual changes . Themeasurements show that the autumn condi ti on , which i s thus characteriz ed by a temperature maximum at a certain depth
,l asts to
the end of the year, whil e already the first hal f of January presentsitsel f with the typical winter cond ition , i . e . with a minimum inthe surface and a temperature ri s ing downwards to 100 fathoms .
The other tables in the report of 1880 show temperature conditions in variou s parts of the Lofoten fi shing sea
,accompanied by
observations on the progress of the fishing . At one and the sameplace the changes of temperature may occur rather qui ckly , butthe general rul e i s however that i t i s lowest in the surface andri ses towards the bottom . As a resul t of the whol e of the obser
vations , the supervising chief emphasizes that good fishing,partly
even rich,has occurred in depths where the temperature has var ied
from 2° to 5° C.
The Lofoten report of 1 881 contains an account of continuedmeasurements at Lodingen (p . 1 79 as wel l as the computations by Mr . KOKK of the mean water temperature at the sameplace for each half month from May 1880 to January 1881 (p .
184 The results stated confirm my above given account .May and October are . months of transition , and the bottom temperature at 1 00 fathoms varies , during al l the changes in the overlying strata , only between and The highest temperatureaverage fall s on August with for the first half of the month ,and for the second .
The Lofoten reports for 1881 also contain accounts of severalmeasurements made at the fi shing station s (Svolvzer, Os tnes - fj ord
,
Raftsund , and other pl aces) . The experi ence made at the O stnesfj ord seemed to indicate a certai n connection between the watertemperature and the fishing . In 1882 a rich fishing took place inthe O stnes - fj ord . The chief of the superv i sion
,Mr . BRODTKOR B ,
says (Defot rep . 1882 p . 77) that in l ess than 8 we eks more than6 milli on cod was brought up from the sea. The measurementstaken showed that the temperature at 60—80 fathoms vari ed inFebruary and March between 5° and Q uite commonly , however
,
“ floi t- redskab” (floating tackle) was used , so that the fishingchi efly was done in water of 4°—5° C .
Also in 1883 measurements were undertaken in the O stnesfj ord
,but
,al though the temperature in February and March does
not seem to have differed much from what i t was in the corresponding months of the previous year, the fishing did not succeed .
In 1884 temperature series were taken in the R aftsund . Thesupervi sion chief
,Mr. KNAP, state s that the best fishing was made
at a depth of 40—50 fathoms , the temperature of the correspondingstrata being 4° Stil l the nets were preferably used at 60 f.
,
and at thi s depth the temperature was higher , nearly up to 6° C .
In 1885 and 86 measurements were undertaken ofi the fishingsta tion Hopen . The first year 5° was reached at 30—40 f. byobservations in February and March
,and the fishing was very
good .
On March 5th the following temperatures were noted
At 0 fathoms C.
1 0
20 4° .O
30
50 5°.O
60
In 1886 the fi shing off Hopen was not a good one,whil e on the
con trary i t succeeded very well off Henningsvaer . The temperature,
from the surface to 50—60 f. , was , from March 1 1 th to April 3 rd ,rather unchanged in the fishing waters off Hopen . Thi s i s of interest
,
because many measurements from the prev ious year had shown amost unstable and very variable di stribution of temperature .
The measurement on March 1 1th giv es these results :
At 0 fathoms C .
1 0
20
30
40
50 3 ° .O
If we compare thi s tabl e with the measurements ofMarch 5th1885 the difference i s strik ing .
In 1887 no temperature measurements were undertaken bythe supervi s ion servi ce , but Envann ME ISF JOBD , the captain of afishing boat , employed a d eep w ater thermometer in th e executionof his profess ion , and thought i t to have been of great serviceto him .
In that year appeared professor MonN ’
s well - known work“Depths , temperature , and current s of the North Ocean ”
. Profeasor Monx has here giv en a description of the natural condition of the whol e of the North Ocean based on the knowledgeobtained by the Norwegian expedi tion s of to 1 878. Thework besides contains a great deal of information on the hy
drography of the fishing banks and fj ords . Several of theseresults are of special importance for the hydrography of the Vestfj ord and the Lofoten banks
,and I shall at the end of the present
chapter , mention some of the facts for comparison with my ownmeasurements . In 1888 no measurements were made by the supervi sion , but Envasn ME ISF JOBD went on constantly employing histherm ometer , and was confirmed in the bel i ef in its practical u sefulness . The fol lowing year five boat - captains had thermometers
,
and all express the opin ion that the cod was to be sought in waterof 4—5° C .
The year 1890 seems to have shown special conditions for thefi shing according to the report of the supervi sion Chi ef, M r . KNA P.
The cod at an early peri od migrated to the shores,pressing into
fjords and bays . A good fi shing could thus go on close to the shoreat a depth of 5—10 fathoms . It i s true that only a few measurements were taken , but these at any rate do not seem to indicateexcepti onal temperatures . Thus it does not appear that for in stancethe higher water strata have had a higher temperature than usualy .
I n the years 1891—92 the government cau sed temperaturemeasurements to be undertaken in Lofoten on a greater scal e .
They were made by marine l i eutenant GADE , who publ ished the
results in ”Temperaturmaalinger i Lofoten 1 891—92
, Kristi an iaThe whole fishing sea of Lofoten was thus for the first
time subj ected to a systematic examination as to the occurringtemperature conditions . In 1 891 the lowest temperature C .)was measured in the surface of the O stnes - fjord, on March 1 6th ,and the highest C .) at 75 fathoms on March 28th on theedge south of Skraaven . The temp . of 6 ° was u su ally reached at75—1 00 f. The highest surface temp .
, C.
,was measured on
Feb . 26th in the R aftsund . In 1892 the temperature conditionsdiffered very much from those of the previous year . About themiddl e of January there was in Vestlofoten about 5° in the surface
,
and at the bottom of th e bank,in several pl aces 7° and more .
Even in East Lofoten - the surface temperature at the end of January w as about In the course of February and March thetemperature decreased in the surface
‘
strata,but the deeper strata
constantly k ept at about Temperatures of above 7° in winterhave not been found in Lofoten
,n either before n or afterwards ;
the condi ti on s of the fishing sea must certainly have differed muchfrom the usual on es. The comparative particulars of the progres sof the fishing given by Mr. GA DE show that the fishing went onwithout any difference in water of 4°—7° C .
In the years 1 893—94 no observations were undertaken undergovernment authority , but several boat - captains used the thermometer , and the belief in the usefuln ess of thi s in strument waskept al iv e.
By agreement between commodore KNAP and dr. HJOR T,samples of the sea w ater were taken in 1895 by the captainof the saving sl oop ”Liv “ in the fishing sea off Henningsvaer .Besides , Mr . KNAP caused samples to be taken at several otherplaces in East Lofoten . The resul t of thi s work i s p r inted in dr .H JORT
’
s book (”Hydrografisk
- biologiske studier over norske fiske
ri er“ , p . 1 40 The temperatures giv en there show a normalcharacter , and the sal tness of the surface vari es between and
p ro mil l e . The saltness i s slowly increasing from the surfacetowards the bottom . 5° C . i s reached at different depths
,the
saltn ess as a rul e then exceeding 34 In the autumn of 1 895Mr . HJORT himself undertook an expedi tion to Lofoten (hydrogr.
tabl es A . In 1 896 captain BIE and myself took 5 sectionsin the coast sea from Stavanger to Lofoten
,after which we made
observati on s in the Lofoten fi shing sea,partly in saving sl oop s
,
partly in steamers . Besides w ater sampl es,plancton was al so
taken .
In the winter of 1 897 I undertook alone observations inLofoten
,Vesteraalen , and Ofoten .
Professor MOHN has in hi s above mentioned work (I. e.) collected a great number of in teresting facts about the seas that surround Norway . However
,as it i s not my task to give a general
v i ew of the hydrography of the North Ocean , I w il l from Mr. MOH N’S
work only quote what i s most n ecessary for il l ustrating the l ocalcondition s in Lofoten . From the tabl e at page 49 w ill be seenthat the di stribution of temperature on the edge off Lofoten presents itself thus
Q
1877 June 29th. Lat . long . E .
0 metres C.
91
183
366
549
732
914
1083 1 ° . l 2
Not far from Rest the North Ocean Expedition measured onJune 28th 1877, lat. l ong .
0 metres C .
18
37
55
73
91
1 15
At the mouth of the Vest - fjord was found on Jun e 22nd 1877,in l at . long .
0 metres C.
1 8
37
55
73
91
1 10
1 28
146
183
2 19
256
According to Mr . Mom : (I. c.,p . 87) th e following series was
observed from the surveying ship ”Hansteen “ on August 2 l st 1 885
at the mouth of the V est- fj ord :Lat . N . Long . 1 3 04
' E .
0 metres C.
25
50
70
1 50
200
Bottom 280
From the deep basin of th e innermost part of the Vest- fj ordthe exp edi ti on measured
June 2 1st 1878, l at . 68° l 2’
, l ong . E .
0 metres C.
18
37
73
1 1 0
1 46
183
366
549
624
Besides the temperature measurements in summer taken by theNorth Ocean Exped ition and the ”Hansteen “ , we have al so the observations of dr . HJORT from the summer and autumn 1895 (see hyd rographical tabl es A . H ) . The l atter show a temperature of 6—7° ata depth of 200 m . , with a saltn ess of about 35 °
/oo. The 35 p romill e water ri ses i n the summer to a height o f about 40 metre sfrom the surface . As a remainder of the winter cold , a temperature minimum is found at a certain depth in thi s l ayer with a highdegree of sal tness . From the observati ons of d r . HJORT appear sfurther that the 35- curve in the course of the autumn i s againl owered
,whil e the summer heat has sp read down - wards , so that
the deep layers late in the autumn are warmer than at any otherseason .
The temperature changes of the seasons take a somewhatdifferent course on the banks and in the open sea from what theydo in the fj ords . For the Vest- fjord , in my opini on , the accoun t.that has been given for Lodingen i s upon the whol e correct . Inp rofessor H ELL A N D
’
S work “Lofoten 0g Vesteraalen” the physi cal
condition of th e Lofoten sea in winter i s thus characterized (p . 1 17)“ A . The 35 and 34- curves are l owered stil l more down than
in the autumn .
B . The temperature at a con siderabl e depth (about 200 m .)i s as a rul e sometimes Hence it decreases towards thesu rface . The degrees of warmth in the different years undergogreat changes according as greater masseS '
of colder or fresherwater form a lay er above the 6°—7° water . Therefore
,the surface
temperature i n February—March vari es from 5° to of wh ichnumerous instances are giv en by temperature measurements und ertaken in Lofoten .
”
This description of the winter condi tion in i ts general featuresi s suffici ently supported by observations .
When in the fol lowing I am going to treat of certain detai lsof the Lofoten hydrography
,I shal l especial ly have in v i ew the
condi tion of the sea du ring the first months of the year,that is
du ring the time that the great cod fisheries take pl ace .
From my tabl e s i t wil l appear that in the two winters 189697 there was in the West- fj ord at a depth of 200 m . a temperature of 6°—7° C. In most cases 6° were al ready reached at1 50 m. ,
when the temperature has been 6° or more , the sal tnes shas been greate r than At 200 m . the sal tness verymuch approached to 35 At the mouth of the Tjeld sund Ithus found (24 Feb . 97, no . 486) at 200 m .
,temperature
being In the Ofoten - fj ord (24 Feb . 97, no . 489) I measuredat 300 m . a temperature of the saltness being afterwardsdetermined at °
/oo. From the surface to at l east 1 00 m .
the temperature kept at sal tness v arying from tothe 6th degree being reached at 1 50 m . This l eads to two
essential conclusions , v iz . that the ocean water exi sts even in thedeep of the i nner fj ords in winter , and that the col d fjord - watermay have a considerable volume . Thi s circumstance i s no doubt ofgreat importance in regulating the temperature on the Lofotenbanks
,as during continuous land - w ind the fresher and colder water
i s pressed out,from the fjords of th e continent, and in to the Vest
fj ord , whereby the temperature on the banks i s l owered . Thatsea- winds have the opposite effect may be concluded a priori , andhas several times been proved by experi ence .
the win te r. ” That the surface temperature in winter, at harboursor close to land general ly , i s lower than further out, has constantlybeen confi rmed by experi ence . Even though the land he a com
paratively small i sland , i t has proved to be the case . Thus onM arch 13 th 1896 the surface temperature in the Rostnes-Vaag
(View ) was C., whi le about 3 mile s 05 land I measured C.
As a ru le,the saltness too i s l east n ear the lan d . I will giv e a
few in stances chosen at random
February 25th 1897.
Liland harbour , Ofoten - fj ord t . C. , 8 .
°/oo
Out at sea , off Liland .
At mouth of Ofotemfjord
March 18th—1 9th 1897.
Secti on across the Vest- fj ord (Groto—Svolvaer) .At Groto t . C.
, 3 .
°/oo
Six mil es off GrotoIn the middl e of the Vestp fjordBola , near Svolvaer
Thus it seems to be a rul e that in winter temperature as wellas saltn ess i s highest along the m iddl e of the fjord , a loweringtak ing place to e ither side . I have b efore mentioned that the waterlav ers on the outer banks show a greater homogenousness in temperature and sal tness than in the fj ord s and on the inner banks .Thus it h as al so been shown that in the harbours o f the outers ide of Vesteraalen the water i s exactly of the same saltness asfurther out
,while however the temperature i s somewhat l ower on
account of the coldness of the land .
In a paper in the transaction s of the Kristiani a Videnskabsselskab for 1873 . professor Moan ha s discussed the effect of ourrents on the temperatures of the water and the air .
Mr . Moms here emphasi zes as the resul t of hi s own Observation s that the surface temperature in the streaming water of narrowchannels i s i n summer lower than at neighbouring places w here
the waters are wider . It i s al so suggested that in w inter the surface of streaming water i s somewhat warmer than in places wherethe water i s at res t
,but that the d ifference i s l ikely to be small .
The author all eges many i llu strating instances that the differencementioned can be quite considerabl e
,even as much as 3 ° C. The
phenomenon is , according to Mr . Mons , explained thereby that thecolder water, on account of the streaming motion , i s drawn up tothe surface .
During my expedition in 1896 , I made a few observationssupport ing Mr . Mos s ’s theory about the win ter temperature instreams . Feb . 14th 1896 I measured off Kverven near Bergen3 ° in the surface , in th e Vatlestrom south of Bergen furtherdown in Vatlestrommen and in the Kore- fj ord on the samed ay C. In the wel l known Mosken- strom that runs betweenLofotodden and Veero , I have also perceived a small d ifferenceof temperature between the surface of the stream and the surrounding Open sea (see hydr . tables no . 202 With al i ttl e increase of temperature al so follows a corresponding smalli ncrease of saltness . It i s obvious that the increase of temperature in streams in w inter i s rather sl ight
,j ust becau se the increase
in temperature i s quite trifl ing in the upper water layers .
10
The local condition s of the Lofoten streams are of no smal limportance during the fishing, as a strong current i s a hindranceto the use of the fishing tack l e . The current caused by the tidei s very much differing in strength, and there are great irregularities in i ts d irection . It often happen s that the d irection of thecurrent n ear the Lofoten i sl ands i s quite opposite to what i t i sfarther up the Vest- fjord . Thus for in stance on March 26th 1 896
I observ ed , 8 mil es off Reine , a sharp boundary between a southwesterly curren t and an easterly one , the former of which wasnearest to Lofoten . That thi s was no mere chance i s proved bysome statements I received from captain A . StinE N SEN of observationstaken at Reine in Apri l of the same yearApril 6th and 7th at 10 e .m. the current ran westwards about 8
mile s off Reine,wind being SW .
April 8th, 1 2 noon , wind NW, near Lofoten an easterly current,8 mil es off Rein e a westerly curren t .
Apri l 9th, at wind SE , near Lofoten easterly current , 6mil e s off Reine westerly current .
Apri l l oth, 2 p .m . , wind SW ,current condi tions the same as on
the previ ou s day at 2 p .m.
April 1 1th, 4 p.m.,wind NE
,the current n earest Lofoten easte rly
,
and about 8 miles off i t was westerly .
This at any rate shows that the directi on of the current cl oseto the i slands and farther up the Vest- fjord may differ for severalcon secutive days . It i s most l ikely that thi s is the rul e . Mymeasu rements on March 26th 1 896 showed different surface temperatures at the two sid es of the boundary of the currents
,the tempera
ture of the east - running current being and of the westrunning on e C . In saltness too there was a small d ifference
(see hydr . tabl e s, no . 2 19,
I cannot wel l l eave the present chapter wi thout once moremen tion ing the much debated question of the dependence of thefishing upon the temperature of the sea .
From what has been said above i t will have appeared thatthe temperature measurements of the first years seemed to l ead tothe conclusion that the use o f the thermometer might be of practicalservice to the fisherman . It i s however quite a common thing thatat first too much importance i s attached to the bearing of sci entificdiscoveri es upon practical l ife . People will see assi stance and improvement where such are really not at hand . I therefore think that nogreat importance can be attached to the few statements we have fromfishermen about the help Obtained from the thermometer in theirwork . Nor can i t be denied that 5 degrees as the best temperature for fishing has been made doubtful by the investigations ofrecent years . Mr . GADE
,as before mentioned , found that good
fishing was carri ed on in water of 7° C. , and I haveascertained that about the middl e of March 1897 there was goodfishing on the banks from Henningsvaer to Bal stad
'
in water of 3degrees . In the month of March , when the chi ef fishing takesplace , the thermometer can consequently be of no guidance to thefisherman because the scope i s too great (3—7°
A li ttl e cod-fishing I have al so seen going on in water of 2degrees (Cstnes- fj ord).
The fi shermen state as a common experience that the cod atthe beginning of the season most often keep s to the fjord edge in
rather deep water . The reason i s supposed to be that the fishdoes not like to enter up into the colder water ion the banks .There may be something true in this , but i t i s al so possible [th atthe stay of the fish on the edge for some time before sp awning iscaused by the circumstance that most food i s found there . It hasbeen supposed that the cod dur ing the spawning time eats next tonothing . It i s certainly true that a great number of the s tomachsexamined have been empty and contracted , but thi s may asmuch be caused by want of food as by want of appeti te . Severalci rcumstances
,however
,bear evidence that the cod eats even
close before spaw ning , and it i s therefore likely that i t stay swhere most food animals are found , i . e . on the edge . Whenthe spawning time approaches
,the fi sh goes up on the banks
to shed its roe and milt ; i t i s then of course caught in moreshal low water. That temperature has any es sential influence onthe migration from the edge to the spawning grounds
,I do not
think can be maintain ed,after the observations hitherto made .
From the reports of the supervi sion chi efs i t i s cl ear that in someyears large shoal s of cod , already at the beginning of the fishingseas on
,migrate into fiord s and bays , where the fishing then takes
pl ace in comparatively shallow water. At the same time the exi
stence i s reported of some ”aate
“
,e . g . herrings or cuttlefish
,and
i t seems undoubtful that the disturbance in the normal migrati onof the cod i s caused by this ”
aate“
. But this al so proves thatfood is of as much importance as temperature . Nor have wehitherto any observations to support the idea that the presence of”aate
“ i n thi s case i s owed to exceptional physi cal condition s ofthe upper layers ; on the contrary the few tempe rature observationswe have from such years do not at any rate testify to anythingunusuaL
At the present standing of the investigations,the opinion seems
therefore most reasonable that the temperature of the water exer
cises l ittl e i nfluence on the fishing in Lofoten . The year 1 892 forinstance gave a moderate produce
,notwith standing that th e 5
degrees curve lay high up in the water .Dr. N . KN IPOW ITSCH
”
) has publ ished a l i st of fishes exi s tingin the Murman Sea and the W'hi te Sea . According to thi s authorthe cod is very general in the White Sea : ”Am haufigsten im
Annuaire du mus é e z oologique d e l ’acad émie impé riale d es sciences d eSL - Peternbourg. 1897, no. 2
, p . 144—158.
1 1
Golfe von Kandalakscha,NW- Theil des Weissen Meeres . Great
quantiti es occur at the Murman coast, where it i s the obj ect oflarge fisheries . The most easterly place on the said coast wherecod -fishing i s carried on on a l arge scale i s Wostotschnaja Liza
(KN IPOWITSCH ) . Thus, general ly speaking, i t may be sai d that theWhite Sea forms the l imit of the extension of the cod to the East .This i s certainly not accidental . Mr . Km pow rrscrr (l . c.
,
-
p . 1 55)notes th e Murman coast as belonging to the warm area . Thebottom temperature i s
.
nearly without exception above 0 ° C. duringthe warm season ; there i s li ttl e formation of ice in winter , and nodrift ice . In the White Sea the summer temperatures in the
'
upper
layers are rather high , but during the long winter large masses ofdr ift i ce exi st , and in the deeper l ayers the temperature in certainplaces i s all the year round below 0° C . To the east of theWhite Sea the bottom temperature
,even in the warmest months
of the year , i s below 0 ° C. , and during the greater part of theyear drift ice occurs in great masses . Temperature thu s puts al imit to the hori zontal di stribution of the cod ; i t i s exclusivelyconfined to the warm area ; the 0 - point i s not exceeded .
If thi s i s appli ed directly on the conditions in Lofoten,i t may
at once be noted that the temperature on the u sual fishing'
banks
i s n ever but as a rule 2—5 degrees above zero . So far,the
temperature of the water should never be a hindrance to the fishing .
Such a conclusion , however , must be made with a great deal ofreserve . Allowing it to be it a fact that 0 ° C . i s the lower limitto the accomodating power of the Species , we dare not directlyconclude that ind ividual s usually l iv ing in water of 4°—6 ° C. woul dvolunteer up into water the temperature of which greatly approachesthe boundary that puts a l imi t to the horizontal di stribution of theSpeci es . I do not think , however , that between the migrations o fthe cod and the physical conditions of the water layers exi sts thatclose co nnection that the investigation s of recent years have asoertained in the case of the herring . An abundant occurrence of foodanimals certainly contribute s far more to keeping the cod gatheredin one place than the ci rcumstance that the water i s 5° C . N or
i s it'
improbable that fluctuations in the fishing,partly at any rate ,
may be ascribed to changes in the amount of l ower animal s gatheredon the banks . Bottom trawling in one and the same place , on eyear after another
,has produced facts indicating that the fauna in
some degree changes character . Our knowledge of these things ,however
,i s v ery deficient .
0. Biological Investigations.
a . Observations concerning fishes, especially cod (Gadus callan‘
as,
oonocrcan inve stigations of the sea for a practical purposemay be said to date
,in the case o f our country from the
year 1864 when professor GEOR G Ossi ax Sans started his obser
vations during the Lofoten fi sheri es . Al ready the fol lowing yearSans made a d iscovery greatly calculated to create a sensation ,when he proved that the spawn of the cod floats and goes throughits development in the open sea . Because however the resul t wasonly publi shed in the Norwegian language
,th is di scovery did not
attract the attention it deserved . In the years 1 864—70 Mr . SAR Swas engaged in studies of the development of the cod - fry and otherci rcumstances relating to the natural hi story of the cod
,the chi e f resul ts
for each year being publ ished in reports to the home department .Mr . SAR S divided the Lofoten fi sheri es in three phases
,th e
immigration of the shoal s on to the banks,the spawning period ,
and the emigration . The immigration may be sa id to commencewith the month o f January , and lasts to the middl e of March ,which i s the actual spaw n ing month for the masses of cod thatmigrate to Lofoten . The fishing that goes on in the month ofApril may be gen erally sa id to depend on the outgoing shoal s .That the main mass of the cod spawn in March is certainly therul e , but thi s does not prevent the occurrence in the sea of codspawn at the end of Febru ary
,which Sans emphasizes
,and which
I have had Opportun iti es of confirming . Further i t may al so bemention ed in this connection that I have seen female cods havingfi ll ed roe - bags at the beginning of May , though thi s i s only excep
tional . In the year 1865 SA KS undertook artificial fecundation ofcod . After 8 days the fetus could di stinctly be seen
,and i n the
course of 18 days the developmen t of the embryo w as finished .
The expe riments showed that only the roe that allowed of beingp ressed out of the fish by a gentl e pressure
,was fit for fecundation .
Likew i se i t was proved that ev en roe of recently died fish retainedthe power of germination
,and that w e having reached a certain
stage of devel opment w as li ttl e susceptibl e of outward influences .Even i f the sea water was considerably deteriorated
,and the egg
covered w i th fungoids , the devel opment went on rather undisturbed .
Even the recently sl ipped young ones could stand deterioratedw ater but herein an immediate change occurred the momentthe yolk - sac w as absorb ed . When the gil l - spl i ts were formed
the young did not all surv ive coming into deteriorated water.Concerning the spawning i tsel f, Sas s remarks that the femalesstand at a higher l evel in the sea than the males
,which d epended
on the circumstance that both roe and mi l t rose to the surfaceafter be ing shed . Al so , the micropyl e through which the fecundati on was performed turned downw ards
,and the development of the
embryo took place at the lower pol e . In the winter of 1865 Sansal so proved that the haddock , as wel l as other speci es , shed floatingspawn , and during a voyage in the fol lowing summer the mackereltoo (scomber scombrus) was regi stered on the l i st of fish es whosespawn
'
shares the fate of the plancton .
Throughout the years 1866—70 Sans appl ied himself with greatvigour to the study of the biology of the cod
,and his efforts were
crowned with success . At the end of May 1866 he found that agreat deal of cod fry had migrated into the bays and sounds onthe east side of Skraaven . The l ength was then (May 20th) 7—8mm .
, and they were swimming about in the surface of the water ;the stomach contents were found to con si st chiefly of calanides.
About the 1 2th of June the plancton was very abundant , and thetiny fry were swimming v ividly about , snapping after the smallspeci es of calanus . The l argest specimen then had the length of24 mm . Gradually the embryonal fin began dissolv ing into thedorsal and ventral fins
,and in the largest individual s there were
signs of the barbal thread in the form of a small knot at thepoin t of the lower jaw . A peri od of bad weather for some timepreven ted the investigation s , and when fair weather returned (June23rd) i t w as only exceptional that cod fry was to be seen . Aftersearching in vain for sev eral days
,Mr . Sans (5th July) at the
fi shing station of Brettesn es became aware of a very young fishjotting out from under a j elly -fish (cyanea cap illata ) . It proved tobe a young cod , and by examining a greater number of jelly -fishes
he found a great deal of young cods as wel l as haddocks . Fromunder the d i sk of cyanea
,as wel l a s aurel ia , young cods were
frequently taken,the largest being about 40 mm . long and having
5—6 dark crossbands . In the stomach were found Specimen s ofan amphi pod (hyperia) , which leads a parasiti cal exi stence on the
jel ly -fishes. Thi s circumstance seemed to suggest a reciprocal usefulness of the young fi sh and the jelly-fishes.
latter , thus tak ing the character of sta tionary fjord fish , anotherand larger part move further and further out on the ocean banksand the large edge towards the deep of the arctic sea , whence theythen return ripe for propagation . At thi s period they d el i ver theirtribute to the Lofoten fisheri es , but the greater part of those thatescape the fishing tack l e , retu rn , after having spawned , to theiroceanic l ife . Afte r the Lo foten fisheries there i s usual ly the“skraapfiske
”
,which is most successful in Vesteraalen ,
for instanceatGaukvmro. This seems to indi cate that the fish-masses on returningfrom Lofoten move northward . Even late i n the summer somestrav specimens of the Lofoten cod may be caught , and these hav eas a rul e an emaciated appearance .
The principal features of the li fe of the cod , as stated above ,may be modified in different ways . Mr . Sans giv es in stances ofthi s in hi s report for 1870 . In the month of June the sand eel
(ammodytes fabianus) draw near the shores in orde r to spawn .
Consequently masses of cod, small and large , pursue it . By openingthe stomachs of cods taken
, Sans found that the contents almostexclusiv ely consi sted of ammodytes , especial ly at the beginning ofthe migration of the latter fish . Afterwards , when young herringsappeared in numbers in the same pl aces , the sand eel was refu sed ,and cod , as wel l as green cod , were found crammed with youngherrings .
On the basis of Mr . Sas s ’ s investigations and material s , professor has given the fol lowing measures for the youngof the ocean cod
V, month ol d , total l ength 7—8 mm .
1
2
3
4
5
1 20 1 30
about 1 95240
400—500In the summer follow ing on their hatching the cod
,at l east
a great part of them, are supposed to move out upon the outerbank s , i n order to return , at three years of age , rip e forpropagation . For ocean cod ripe for propagation
,COLLETT (1.
puts the l ength at 650—700 mm . , while of the fjord cod the smallestind ivi dual s ripe for propagation have the l ength of 350—400 mm .
A.few times I have undertak en measurements of young cod caught
close to the Biologi cal Station . On August 26th, 1895, the aquariumw as suppl i ed with a number of young cod whose length was foundto average about 80 mm . On September 15th they al l di ed fromwant of ai r as the condui t had been choked . In the mean timethey had been wel l fed on myti lus edulis , and the foll owing sizeswere found : 104, 88, 87, 93 , 85, 85, 98, 97 mm . ,
average about90 mm . In 20 days the growth was consequently about 1 0 mm .
For another and l arger l ot, the feeding of which had been l ess regul aron account of the greater number , the increase during the sametime averaged 6 mm . Thi s observation from the aquarium
,however
,
Professor Connm , Norges Fiske, p . 104—107.
cannot of course be directly applied to the rel ation s in free nature .
This fry that on August 26th had an average length of 80 mm .
“
were of course belonging to the progeny of the year , after thenormal Spaw ning time . At the beginning of Jun e of the foll owingyear a few shoal s of young cod were seen near the station bui l ding
,
some of which were caught and had a l ength of 140—2 15 mm .
These could not bel ong to the batch of the year , but at the sametime they were also rather too small to be in the ir second year.Even supposing that the Spawning had taken place in the mon thof February , they were stil l too large to be of the fry of the year ;i f however we suppose the spawning to have taken place in May,
this fry w ould have been one year old , and even under that supposition they difiered rather much from the normal s ize that professer Sans has found for the one year old progeny of the oceancod in Lofoten . In another part of the coast, i n the harbour ofLarvik
,I undertook , Nov . 25th, 1896 , some measurements of smal l
cods . T he l ength was here 190—200 mm . , which very wel l agreeswi th the measures given by Sas s for the corresponding stages ofdevel opment from Lofoten . The stomach was crammed with em
phipods (e . g . gammarus) and decapods (e . g . crangon vulgaris) .
T he maj ori ty of the fry of fishes i s obl iged to l ive on planctonorganisms
,and whil e some cont inue plancton eaters al l their l ife
(e . g . herring, sprat, there are others that, after eating nothingbut plancton during the first part of their l i fe , l ater o n change toa mixed food of plancton and necton . The green cod (gadus sirens)i s no doubt such a one
,probably the mackerel too . Further
,
there are some that rather soon leave off feeding on plancton , th eplace of thi s food being taken by the rich crustacean fauna of thel i ttoral region . Thi s i s the case of the cod
,and Sans has shown
that for the Lofoten cod the change i s made when the young hav ereached the length of 50—60 mm . That the young green - codcontinue feeding almost exclusively on plancton un til they are atl east on e year old
,seems to me evident from the observations I
have made ; though more about thi s l ater on . Thi s circumstan ceal so explains the difference existing between the fry of cod and thatof green - cod in the cho i ce of their staying place . At the periodsduring which sufficien t food i s found in the surface layers
,the
green - cod fry stay at shal low p l aces ( in small bays and in barbours) , whil e they move into deep e r water in the typical wintermonths , when the plancton i s extremely scarce in the upper layers .
As for the grown -up fish (cod , green - cod,
I have in thefollowing tried to give a somewhat detail ed description of theirfeeding condi tions .
The food of the cod .
The cel ebrated knower of fishes , M r . KROY ER , wri tes aboutthe cod that it may , on account of i ts veracity, be regarded as
the enemy of nearly all sea animals that i t can master . It i showever of considerabl e interest to see what turns up in its stomachin different p laces and at d ifferent times . I have therefore examineda great number of cod stomachs . The cond itions under which thecod feeds in our waters have of course been in vestigated before ,especial ly by the professors Connnrr and Sans . In “Meddelelser
om Norges fiske i aarene 1 875 p . 65, COLLETT writes : “The
animal forms that contribute the chief food for the l arger individuals
of thi s speci es are nearly g
alw ays caught on the bottom of the sea ,or close to i t
,and largely consi st of!decapods and echinoderms ,
as wel l as different bottom fishes . ” In July 1 878 COLLETT foundnumbers of cod stomachs fi ll ed with hyas am neus and ophiopolis
aculeata ; he fu rther al so frequently found some small holothurides,as well as ann elida and gephyrea . Of fi shes he found especial lyicelus, centridermichtys, an d the young of anarrhichas, sebastes
,
lump em cs , chirolophus, centronotus, cyclopterus, and other bottomfishes . Previ ous inv estigation s have also shown that the fishes thatparticularly in great masse s supply food for the cod are mallotusvillosus
,clupea hare'ngus , and ammodytes fabianus . The latter three
species are on a large scal e used as bait for the cod . Dr . P .
OLSSON (A cta un i t-emirates L unden sis, VIII, in hi s “Iagt
tagelser ofver skandinaviska fiskars foda” , menti ons the followingfi shes as h aving been taken from the stomachs of cods : Gadus
merlangus, g. ceglefinus , g. minutus, clupea, coitus scorp ius , p leuronectes limcmda . G . O . SA KS , by examining the stomach contentso f cod caught at Spitsbergen
,found indiv iduals of the arctic species
o f lycodes . Final ly,as a rare occurrence
,argyrrmelecus olfersii and
argentina sphymma have been found in the stomach of gadusca llar’ias . The only specimen of macrm '
us coelorhyncus (Ri sso) thati s known to have been observed at the coasts of Norway
,was found
by Mr . Sans in the stomach of cod (at H erlovaer, no rth of Bergen ,Feb .
The following fishes I have taken from cod stomachs : l iparis5p , sebastes marinas , chirolophus galerita , anarrhicas lupus, gobia s
3p . , gadus rallarias. hippoglossoidcs platessoides , g. (Pylefinus, clupea
harengus .
In order to give a picture of the variety of organisms thatcontribute to the feeding of the cod
,I here giv e descrip tion s of
the stomach contents for d ifferent places on the coast of Norway .
Feb . 20th, 1896 . Ocean cod (skre i) caught on - the banks off Kri
stiansund N . A great number of the stomachs were empty .
Contents : Herrings , decapod crustacea , cypr id 'ina norvegica ,G . O . Sars .
March 6th, 1 896 . Ocean cod tskrei) caught at Svolvaer , Lofo ten ,at 40—50 fathoms . Most of the stomachs empty or contain ing only remainders of the bait . The roe rather l oose .
March 1 8th,1896 . I examin ed a large specimen caught at Ben
ningsvaer, Lofoten . MeasuresFrom end of tail to pectoral fin 855 mm .
pectoral fin to snout 3 1 5
Total l ength 1 170 mm .
Stomach containing : Herrings,s ipho glaber.
A pri l 20th,1896 . Bal stad Lofoten . Out of a considerable number
,
only one had fi ll ed roe - bags . Stomach contents : H ippo
glossoides p latessofdes, ophiurides , &c.
Apri l 30th, 1896 . Balstad . Ophioctcn sp .,sipho 579.
Feb . l 0th,1897. Snudero in Vesteraalen. A number of one
hund red fishes . The largest ones had a l ength of 1 20 cm .
In rather many of the stomachs were found solid obj ects,
only a few were qui te empty,there being at any rate
found a whiti sh semi - l i quid pulp . In the guts the dissoluti on was so far advanced
,that no determination of the
15
con tents was possible,but that the food had been of vari ous
kinds appeared from the colour of the contents. The latterwould be greeni sh , reddish , yellow , greyi sh- white
, &c. A
granulary , reddi sh pulp in the guts testified to the anima1having eaten chiefly echinoderms . In the gut were oftenseen cestodes, and in the stomach mematodes . Of ectoparasites , caligus was common , a few times lemma branchialisbeing observed . The fish examined had been tak en in anet . Besides cods , al so l ings and green cods had beentaken . Several specimens of cod and l ing had been consumed by myxine , which had eaten all the flesh
,and al so
roe , l iv er, heart, 850 . Only the bones and skin were left,
the swim - bladder and the stomach being al so as a rul el eft intact . What remained of the guts was empty , thecontents of the guts had probably also disappeared . Whatmight have been l eft by myxine had been done away with byamphipods . Thus , under the skin of the sucked - out fisheswere found a great number of sp ecimens of hop lonyx cicad a,Fahr . On one occasion w e got up a cod that had onlybeen half eaten by myxine . On cutting it Open
,as much
as 7 specimen s were found of th i s mischievous animal,
which the Lofoten fishermen call “worm ”.
Con tents of the cod stomachsOmmatostrephes todm'
us,
ciona intestinalis, munida
rugosa , hyas coarctatus.
Feb . 1 2th , 1 897. Snudero. Number , 40 . The maj ority empty.Contents : Shell s (pecten) , remainders of decapod
crustacea and ophiurides, sebastes marina s.
Feb . 1 7th,1897. From the fishing sea off Svolvaer . Stomachs
generally empty , in some specimens boreophausia inermis
was seen .
March 3th, 1897. From Hola in Lofoten . Fishes taken on setl ines at a depth of about 50 fathoms . Many stomachsempty
,or only con taining remainders of the bait . The
gut generally w ell fill ed with greeni sh,yellow
,or grey
contents according to the description of the food .
Number examined : 1 00 .
Contents : Pandalus brew/roams
, p andalus 3p , cw 'n
gon almann i, hippolyte polaris, boreophausia inermis, p amthemisto oblim
'
a , opercula of gastropodes . Of boreophausiainermis a considerabl e number were found .
March l 6th, 1 897. Svolv zer. Number : 1 00 fishes . Among thoseexamined was found a Specimen whose liver was greenthroughout. The greater part of the cods stil l retainedtheir roe . Some stomachs empty . Stomach contents : Candalus 8p ,
crango'n almanm'
, boreophausia inermis, tyscm oessa
neglecta , idothea baltfica , p arathemisto oblivia, paroed iceros
Iynceus , hippomedon denticu latus, euchceta 'norvegica, ophi
ura sarsii, modiola mod iolus, opercula of buccinum, ciona
intestinalis , the low j aw of a fish .
The occurrence of ascidians in cod stomachs I haven ot prev iously seen observed , and i t i s probably the firsttime that any copepod has been observed in the stomachof the cod . However , of euchwta norvegica only on especimen was taken
,a femal e with adjoined spermatophores .
March 29th, 1897. Re i ne in Lofo ten . Number : 100 fishes .Contents : Buccinum sp . , bucc i -num undatum, s ipho
glaber. boreophausia inermis , cyprid ina non'
egica, yadus
wglefimw . 28 cm . long .
The maj ori ty had now spawned , the roe - bags wereblui sh - red , and te ste s had not the prominent white col ouras before .
March 3 l st, 1897. Re in e . Number : 250 .
Now that the cod had spawned,many of the stomachs
were empty too ; the contents however indicated that theappetite at any rate had not become l ess than before .Besides remainders of the bait , the intestines of cod wereoften found , in an i solated case was even found a largehead of a cod . The thing i s that the cutting up of thefish is often done while the fishermen are rowing homefrom the fishing places ; the instetines are then throwninto the sea .
Stomach contents : Idothea mglecta, i. baltica, re
mainders of amphipods , remainders of holothurides , ophiurasarsii. onuphis cmwhylega ,
mytilus , sipho glaber, buccinumundatum, opercul z of buccina -m. Some of the cods examined had their stomachs almost crammed with tentacl es ofholothm
'ides . Mr . H J . Osrancaas at Upsala has been goodenough to examine this material , and says that most of thembelong to phyllophorus sp . , and a few to cucumaria frondosa .
Apri l 12th 13th, 1897. Balstad . Number : 400 fishes .In the largest cod - stomachs w ere often found the
intestines of cods , in some even the heads . W i th a brachyOpod (coalflheimia) followed al so the stone to which ithad stuck . That a great part of the smal l stones thatare frequently found in cod stomachs have come there ina similar way , i s mos t l ikely . That the Cod should take“ ballast ” before i t again seeks out into the deep sea
,i s
not v ery credible . At Balstad I found for the first timea starfish in the stomach of a cod , viz . a young specimenof cribrella sanguinolenta , and also a young indiv idual ofsalueta '
endear.
Contents : Strongylocentrotus drobachicnsis,
solastcr
endeca , cribrella sanguinolmzta, ophiura sarsii, operculaof buccinum , pee len tigrinas , lunatia montagu, wald
heimia , anaphia conchylcga, leodice norvegica , nymphon
stromii, hatirages fulvocinctus , amp elisca Sp ., pan dalus
annulicornis, cion a intestinal is .
Here at Bal stad too , tentacl es of holothuridce werevery common . Mr . OS'rEnGaEN mentions one nearly com
plete specimen of stichopus tremulas , as well as tentacl ecoronas and loose tentacle s of phyllophom s sp . The calcareous substances of the sk in and the tentacl es weredi ssolved , as were al so in nearly al l of them the calcareous ring . Among other curiositi e s found in cod stom ~
achs at Bal stad was al so a bi t of orange p eel .
Apri l 28th, 1897] Rest i n Lofoten .
Contents in cod stomachs : Remainders of decapodm istacea, ephaus idw and amphipoda.
Eb'oni the cod fisheries off Kristi a n sund N . (March , 1897) Ihave examined about 900 cod stomac hs . The fish were caught 4miles SW of the Grip l ighthouse . A great deal of the stomachswere empty , or contained only the remainders of the bait ; I foun d ,however , also remainders of fishes and cuttlefish, further crustacea
(decapods , i sopods) and sn ail s .Specification of the contents
Remainders of ommatostrephcs, sipho gracilis, s. fusifmm is,opercula of bzwcinum and sipho, munida rugosa , erangon almanni,
(ega stromii rocinella danmonierw is, cirolana borealis, cypfl dina
norveg ica .
From the fishing ofi'
Kalvaag , Bremanger, in March 1 897, Iexamined about 200 cod stomachs . Simultaneously with the fish ingof cod , spring herrings ” were also being caught
,and the majori ty
of the cod stomachs were fi lled with herrings or herring spawn indifferent stages of development. About half the number of thestomachs examined were fill ed with herring spaw n, and the otherhalf wi th spring herrings . With the spawn foll owed algae , shel ls ,&c. A great part of the spawn was so far developed
,that the
eye - spots were distinctly vi sible . Further, one specimen was foun dof (marrhicas , cm . l ong, as wel l as remnants of other fishes
,
besides specimens of ascid ia mentula, o . f. m . , several gastrOpod sand opercula of the same , galathca sp ., cribella sanguinolenta, &c.
In one stomach were found several ball s of algae . The generaloccurrence of Spring herrings and herring spawn in the cod stomachsdeserves special attention . The largest specimens of herrings observed measured as much as 28 cm . Among molluscs taken fr om codstomachs from the Bremanger fishing may be men tioned : Buccinumumiatum,
trichotropis borealis, nassa incrassata, chiton marmmeus,
margarita gré’
nlmuliea, lunatia mon tagut, cribella sangu inolenta ,ophiu
'
ra sarsii.
Also in March 1898 cod fishing took place off Bremanger. Instead of the cod stomachs crammed with herrings and herring spawnas I had seen them the previous year , the March fishing of 1898 onlysuppl i ed me with rather empty and shrunk stomachs for examination .
In some,however , I found remnants of fishes , among these al so
herrings,but in n o case spawn was found . Generally speaking
,
there seems thi s year to have prevail ed scarcity of food . In thestomachs of cods taken near Bergen in March 1897 were , amongother things
,al so found herrings , and spawn of cottus, while there
were traces of portunus depurator, galathca strigosa, &c.
During the cod fisherie s off Se tra (a li ttl e South of Bergen)i n February 1898, I have further made some observation s about.the food of the cod .
On Feb . 23th, 1898, about 900 stomachs were examined , mostof which were empty and shrunk , as in Lofoten , or only containingrests of the herring bait . In a few specimen s spring herringswere seen ; of other fi shes were found on e sebastes, one gobias ,and indefinable rests of others . Among other things were foundstri ps of laminaria , the j aws of ommatostrephes, many apercula ofbuccinum un datnm,
further specimens of nassa incrassata, lunatia
montagui, margarita grifnland ica, &c. In a few cases were seenascid ia and holothurides, and of larg er crustacea may be notedcancer pagum s, carcinus moenas and lithodes maja. Further maybe mentioned several smal l er amph
'ip oda, one isopod (cega psm'
a,
taken many individual s o f the latter schiz opod in stomach s ofsebastes caught in the Kristiania - fj ord .
Of amphipods in stomachs of green - cod (Feb . 8th, 1897,
Sundero) may be mentioned pa-
rathemisto oblivia, e uthemisto com
p ressa, and mathemisto bisp inosa. The two latter ones have onlybeen observ ed in a singl e local i ty , v iz . at 80 rd in Western Finmark
(G . O . Sans) .During the fishing at Rest at the end of April 1897 there
occu rred , togeth er with the ocean cod , sev eral other fishes , as torsk
(brosmius bw eme) . l ing (molva vulgaris) , haddock (gadus (eglefinus) ,hal ibut (hippoglossus vulgaris) , sea - cat (anarrhicas lupus) , Norwayhaddock (sebaste s marinas) . It was di fficul t to examine the stomachcontents of to rsk and l ing as the stomach as a rul e stood far ou t of themonth when the fishes came into the boat. Only exceptional ly thestomach had i ts natural positi on . In stomachs of l ings I sawbones of haddock (both at Rest and at Sundero) . In stomachs oftorsk were found decapod crustacea, chiefly lithod es maja, the Spin esof which were v i sibl e on the outsid e of the stomach , without howeverhaving pierced the stomach bag . Besid es crustacea I have seenannel ida (Ieodice) in the stomach of torsk . The gut of anarrhichaswas as a rule fill ed wi th a gruel derived from echinodermata.
The largest l ing I saw during my stay at R est measuredmetre . The females had at the end of April unrip e roe .
On the feed ing circumstances of the haddock i n the neighbourhood of Bergen , some observations have b een made .
Mr . GRfEG , curator at the Bergen Museum , has defined thefol lowing form s from the stomach and gu t of the haddock
July 9th, 1897. Hjelte- fj ord .
OphiOphoI-is aculeata, ophiura squamosa, amphiura
squamata, echinocyamns pus illus , lima hians , l . loscombi,
limatula ell iptical , l. subauriculata, card ium fasciatum.
The most common of these forms were lima hians andloscombi, cardium fasciatum,
and ophiura squamosa.
D ec . 16th, 1897. Herlo - fj ord .
Gasterosteus amcleatn s, munida, aega, pecten septem
rad iatus , p . s im i lis, p . v itreus , area pectunculoides , port
land ia tennis, philine scabra, cardiun fasciatum . To therather common ones belonged pecte n vitreus and area
pectunculoides .
Dec . 23th, 1897. Herlo - fjord .
Stichop zw tremulus, ophiopho lis aculeata, ophiura sarsii,
strong. drb’
bachieow is , pecten v itreus .
Echinodermata and molluscs afford,i n our waters as el sewhere
,
the chief quantity of the food of the haddock,but besides
,thi s
fi sh eats bottom crustacea (as munida, raga) , ann el ida , and evenfishes . The haddock may consequently be characteri sed as a typicalbenthos - eater .
At the end of the Lofoten fisheri es young green - cods (gadusv irens jun .) are often used for bai t for the cod . During my stayat Bal stad late in April 1896 , sein es were regularly u sed to catchyoung green - cod , which in large shoals swarmed in the harbour .
The foll owing measures , from the snout to the tail - fin , give a fairidea of the sizes that occurred : Balstad , April 2oth, 1896
,
cm . , 19, 25, 1 3 , 14 , 1 3 cm . Among theyoung green - cod occurred a few small cods , one for instance 3 1cm . l ong
,which however was more l ike skrei than ordinary fj ord
cod . Among the small e r specimens of the young green - cod themajori ty were blui sh - black on the back and blui sh on the sides
,a
few however had a reddi sh tinge on the sides and fins . Ontheir being opened
,the stomach was seen to be much expanded ,
and in the smallest sp ecimens some peculi ar granulary contentswere perceived through the expanded skin of the stomach . Thesecontents soon proved to con si st chi efly of fish spawn
,among which
al so the spawn of the ocean cod in great numbers . When it is considered that every harbour in Lofoten in the spring swarms w i thvery young green - cod which incessantly sn atch at fish- spawn
,one gets
an idea of the enormous destruction that the germs of th e cod areexposed to from the progeny of its kindred . In the stomachs werefound , besides fish- spawn , a great number of cypris and naup lius
stages of cirrip ed'ia, al so microsetella atlantica was observed,as
wel l as another copep od,which profe ssor Sans has defined as
thalcshv'
s yibba , (Kroyer) .
On April 3oth, 1897, I caught, off the quay at Glea (R est) ,some. young green - cods measuring about 1 3 cm . Here too fish- spawnwas found in the stomachs , though not in such a large number asat Balstad the prev ious year . At the time there was however
,at
any rate in side the harbour , not very much spawn . The greater partof the stomach contents con si sted of cirrip ed cmw is ; fur ther thereapp eared larva: of enphaus ida and copep oda, z oea of brachyurdecapod , calanas finmarch'écus , pseudocalanus elongatus , harpacticusche lifer, &c. In the harbour of the hamlet there were at thi s timel arge masses of young green - cod
,a great deal of boats were moored
there , and it was interesting to observe how the small fishes withpredi lection stuck to the shadowy side of the boats . In none ofthe stomachs of the young green - cods that I examined I foundbottom animal s . It i s l ikely that green - cod feed almost exclusivelyon pelagic organi sms
,the younger stages being l imi ted to plancton
,
and the grown - up ones to the larger pl ancton forms (boreophausia,nyctiphanes, parathemisto, &c.) as well as n ecton (cuttle - fish, herrings,sprat, sand eel , capelan , In Lofoten Mr . G . O . SAR S hasobserved that green - cod occur in l arge numbers in the month ofJuly , chasing the fry of the cod as wel l as their own . On oneoccasion the professor even succeeded in making a green - coddi sgorge a coupl e of l i ve young cods . It might appear that thegreen - cod had several advantages in competing wi th the cod
,but
n everthel ess the two species may keep alongside each other inl arge masses in the same area . The cod lack the power of thegreen - cod for cooperation , and the green - cod are l ik ely to make agreater destruction of the eggs and fry of the cod than v ice versa,but as the green - cod does not spare their own young
,which of
course in thei r turn make no diffe rence between cod - spawn and greencod spawn
,thi s ci rcumstance i s l ikely to keep up the balance between
the two nearly related species .On the weight of the ocean cod the supervi sing chief Mr . KNAP
has caused a seri es of observations to be made . Thus the averageweight for the whole of Lofoten was found to be as fol l ow s :
0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
O O O O O O O O O O O O O O O O O
O O O O O O O O O O O O O O O O
During the fishing season of 1889 a great deal of measurementsand weighings were undertaken . The l ength var i ed between 74 and100 cm .
, and the weight of the fi sh in round condition averagedfrom to kg . for different fishing station s . Sometimes Spe
cimene are caught of unusual size . On April 1 3th,1888, two
fishes were caught off Skraaven , weighing 3 1 and 37 kg . respec
tively, and off Svolvaer , on March 1 7th i n the same year,a cod
was caught measuring m . in l ength,and m . roung the
belly,the weight being 43 kg . (HELLAND , Lofoten 0g Vesteraalen ,
p .
On March 23th, 1897, a cod was taken in a n et off Brettes
naes Whose l ength w as m .
, total weight kg.,weight of the
roe kg.
, of the l iver kg . It i s not only in Lofoten thatcod of such dimensions occur . According to Norsk F iskeritidende ,1887, p . 30 1
, a cod was caught June 7th, 1887, at Losvik in the
Tana fjord whose l ength was m . and weight in round condition kg . Of this weight , that of the body was 25 kg. ,
headkg.
,l iv er kg.
,and intestines kg .
In conclusi on I give a l i st of the most important an imals thatare used as bait for the cod in Lofoten :
b. Notes on certain plancton form s .
Galcolam'
a (d iphyes) truncata , M . Sara.
A few specimen s of thi s siphonophor I took Feb . 5th,1898,
i n the Hjeltefj ord near Bergen , at from 0 to 1 90 m . the largestspecimen had a l ength of 15 mm .
Mr . M . has taken the species at Floro in the monthsof September , October , and November .
It has further, been observ ed by the German North sea Expedition of 1872 , July 25th, in the surface , near Lindesnes .
P leurobrachia pi leus , Fabr .
Til l now I have only met with a singl e ctenophor, vi z . p pileus .
It was taken close outs ide the Bergen Biol ogical Station in the
autumn 1896 by the keeper , Mr. GLLMM E . The speci es thus appearedi n samples taken from the Pud defjord from November 1 7th to 24th,
F aun a Li t toral is Norvegia , h. I. , p . 41 .
1896 . Afterwards i t has not been seen at thi s place .\
In thesample of Nov . 17th a pecul i ar copepod al so occurred
,a kind of
monstrilla, of which I have publ i shed a short characteri stic in the
Annual Report of the Bergen Museum for 1 897.
Cyphonautes .
Outside the Biological Station cyphonautes was observed in th eplancton in al l the months of 1 896 and 1897, excepting JanuaryApri l inclusively . For occurrence el sewhere
,see the tabl es . During
the summer of 1 896 colon ies of membranipora membranacea, Linn . ,
were often seen on the glass panes of the aquariums of the station .
These were of course founded by cyphonautes that had enteredwith the water from the conduit .
Bip innaria .
In Feb . 1896 I took bip innaria at several places along thewest coast . The smal l five- armed sea - stars could distinctly be seenon all
,and the arrangement of the processes on the l arvae makes
it lik ely that al l must be cl assed among bip innmv'
a asterigm'
a
Sars . In a su rface sampl e taken in 6 1 ° N . and 3 °
B ,May 1 2th, 1896 , a l i ttl e sea - star was found the appearance
of which corresponds wel l w ith the small ones on the bip -im zaria
mentioned . It seems to have been made ev ident that b. astw igera
i s the larva of luid ia sarsii, whose spawning time must con sequentlybe very irregular as Mr . M . Sans has observed the said larvae inMay
,Messrs . KOR EN and Dam snsnx in the months September
October,and I in F ebruarv .
Spadella (sagitta) hamata Mobius .
Thi s chaetognath I have taken many times , both in the fj ordsnear Bergen and in Lofoten
,but never in shal low water . Mr .
Meme s") mentions i t from the Korsfjord in depth s of from 1 35 to337 fathoms whi le A UR IVIL L IUS, during the Swedi sh ScagerrackExpedi tion of 1893—94, n otes it from 0—1 00 m . in water whosesal tness was and temperature 0 .
Mr. A UBW ILL IUS") gives the length at 18 mm . for sp ecimen s from
the Swedish Scagerrack coast . The largest ones I have til l nowmeasured w ere 24 mm . (Feb . 23th, 1897 ; bet-ween Bart) and Lodingen , 0—190 Mr . STBODTMA N N state s that s . hamata mayreach the l ength of 3—4 cm . , but such large indi vidual s are probably only found in high arctic regions . I have the idea that s.
hamata at our coast i s thri ving best in water of 6°—7° C., andwith a saltn ess of 34—35 In some places , as in the (lstnesfj ord and at Sundero in Vesteraalen , I have observed chaetogo
‘
zata
also in the su rface , but th i s has been another k ind (3 . bipunctata) .
Tomopteris sep tmztrionalis, Stenstrup .
In “Videnskabelige Meddelelser fra den Natuihistoriske Forening i Kjobenhavn
”
,1 849—50 , p . IV , Mr. S'
I'
EN STBUP state s thatthe Copenhagen Museum had received from dr . RINK a great number of specimens of thi s k ind , in part taken a few miles off theNorwegi an coast , in part in the sea round the Orkneys and theFaroe i slands . Mr . STEs s'
rRUP considered i t different from the
form observed in the South Sea by E scnn on'
rz (t. oniscifomnis) .
In “F flnfter Beri cht d er Kommission zur w . Unters . d . D eutsch .
Meere ”,Mr . N osw s (p 1 1 7) has mentioned a form ,
t. helgolandica,
Greef, which in all probabi l ity i s synonymous w i th t. septentrionalis.
Besides in other places , the German Exped ition has al so observedthe form mentioned in the neighbourhood of Lindesnes . Mr . G .
O . Sans has info rmed me that he has often met wi th tomoptm'is
Jahresbericht d er Comm iss ion z ur w issentschaftl . Untersuch. d . Deu tsch.
M. I] , III Jahrg., p . 158.
Daa P lank ton d es Balt ischen Meeres, p . 37 (Bihang t . Kg] . 8. V et.
Akad . Hand l. Band . 2 1 , Stockholm
20
both in the Kri stiania- fj ord and along the whol e W' est- coast as faras Lofoten . In the many plancton samples that I have takenduring the last two years , thi s form has only occurred a singl et ime
,namely Feb . 25th
,1897, in the Ofot en - fjord in a sample
from 0—250 m . Further,dr . A PPELLOF took a fine specimen in
the Bergen By-tjord in the summer 1894. It had a total l ength ofabout ~ 40 mm' .
Calanas finmarchicus, Gunnerus .
Mr . GIESBR ECHT has n oticed that thi s i s probably the firstmar in e p elagic Copepod that has been described . That honourbelongs to the Norwegian bishop JOHAN ERNST GUN N EBUS ( 1 718
The original n ame was monoculus finmarchicus, and theo rig inal descripti on
x
is found in Det Kongelig Norske Videnskabsselskabs Skrifter” . This copepod seems to occur in the planctonat our coast at any time of the year
,at l east the females , the
mal e s on th e contrary b eing rarer . Mr . GIE SBBE CH '
I‘ in hi s “Mono
graph i e ” giv es the fol lowing measures for the femaleAt Napl es mm .
Gibral tarSpi tsbergen , th e l argest ones 4
The grown -up males are stated to vary between —32 mm .
I have undertaken a number of measurements of both sexes .Feb.23th, 1897; between Bari) and Lodingen ; 0—200 m .
Q mm .
6‘
or
Feb . 24th, 1 897 ; off the mouth of the Tjeld sund ; 0—200 m .
Q mm .
07‘
July l st, 1 897 ; 1 5 geogr. mil es north of Jan Maya ; 0 m .
Q mm .
Feb . 1 4th , 1898 ; H erlofjord near Bergen ; 0—400 111 .
Q mm .
o"
From thi s will be seen that even in the deep of the fjordsnear Bergen the mal e may reach the l ength of mm .
,whil e in
the arctic sea the female can reach a l ength of 5 mm . The upperl imit of variation i s thus somewhat extended .
Calanus hyperboreus, Kroyer.
9Apart from the difference of si ze , the female of c. hyp erboreus
i s easily di stinguished from c . finm. Q , the lateral corn ers of the5th body- segment being po in ted in the former
,whil e they are
rounded off in the latter. The arrangement of teeth on the basal
joint in the fifth pa ir of feet (fig . 28) al so gives a good mark ofdi stinction . The in terval o f variation is stated by Gmssancnr tobe mm . Having taken several Specimens of the said formboth in Lofoten and in the Ofoten - fjord
,I give here some measures .
G . 0 . Sara. Thi s speci es i s said to have been found in Kvaanangenand at Tromso . In the summer 1897 I showed to professor Sansa preparati on of a copepod that I had been unabl e to identi fy .
H e then declared it to be the very madinopsis bradyi, and afterwards informed me in a l ette r that the sai d copepod had beendescri bed and draw n by Mr. a r (A monograph of the copepodaof the British Islands , I , p . 46 , pl . IV, fig . 1
The spec ies was , however, there w rongly identifi ed w i th pseudocalanas armatus , Boeck , which accord ing to Mr . Sans i s anotherspecies . As Mr. Sans , in hi s gigantic revi sion of Norwegian crustacea
,w i l l soon come to the copepoda
,I shal l do nothing but
here note the occurrence of und inopsis bradyi at the fol lowing placesMarch 14th, 1896 ; Vestfjord (67
° N . ; 13°
In plancton 0—200 m .
March sth 1897 ; O stnes - fj ord in Lofoten .
March 7th. 1897 ; Trold - fjord in Lofoten , plancton 0—65 m .
Besides , I have thi s year taken several specimens of the sp ec iesfrom the fjords near Bergen .
Euchceta norvegica , Boeck .
Mr . Boncx to ok the specimens of thi s speci es on which theo riginal descrip tion was based , at a depth o f 300 fathoms , offSkudesnes .
Mé nw s and Sans , which investigators have giv en extensive d escriptions of the animal . In the North Ocean Expedition , the 3 . nor
vegica was noticed at 1 2 different stations,and always from a
con siderable depth .
In Lofo ten I have observed the Speci es in plancton samplesfrom 0 - 100 m.
, viz .March 23th
,1896 ; Reine , Q length mm .
March 26th, 1 896 ; Reine , Q length mm .
I have fu rther taken a female wi th attached spennatophores
i n the stomach of a cod caught near Svolv zer,March 1 6th, 1897;
l ength mm .
l argest specimen s from the North Ocean Expedi tion,but thi s con
siderable l ength i s not likely to be reached by the forms exi stingin our fjords .
It has afterwards been mentioned from our waters by
Mr . Sans gi ves 1 2 mm . as the measure of th e
Centropayes typ ions, Kre ver .
The North Ocean Expedi tion observed the Species,besides in
other pl aces , on June 28th, 1876 , at st . 26 N .,
It probably goes somewhat farther northwards,but Mr. BOECK i s
scarcely right in saying that i t occurs in great numbers along thewhol e of our coast . It was found
,together with some other cope
poda, in a surface sampl e taken by capt . TH OV SEN in the NorthSea, March 8th , 1898 (57° 2 1
'
N ., 2° 27
' The surface temperature at the place was 7° C.
,sal tness
Ce ntropages kumetas, Liljeborg,
has not yet,to my knowledge , been observed as far north as Lo
foten . The North Ocean Expedition took the specie s in severalplaces . Outside the Biolog ical Stati on , 0 . kumetas has ch ieflyappeared in the late summer and autumn , simul taneou sly with c.typ imcs . Both these speci es were however al so found in the lin eStavanger—Newcastle on March 8th, 1898, in the surface of the sea.
mm .
Temora longicor nis, O . F . Mull er .
Mr . Boacx says that the species i s v ery common in the K ristiania- fj ord , but not quite as common on the West- coast . Duringth e North Ocean Expedi tion i t was observed
,besides in other
places,also at st . 1 24 N .
,.
6059' E .) on June 1 7th, 1877.
I do not th ink i t has as yet b een taken north of that lati tude .The speci e s in summer and autumn occurs in a large number ofindividual s in the fj ord of Bergen . In the prol ongation of th eBy
- fjord on which the Biological Stati on i s si tuated , tcmom occurredin the sample s of every month in 1896—97, with the exception ofMarch , and for the months Jun e—October incl . i t was very common indeed . In Lofoten i t was , at any rate in the winters of1886 and 1887, extremely rare .
Met'rid 'ia hibernica, Brady Rob .
Mr. AKSEL Bos cx described,i n Tran sactions of Kri stiani a
Videnskabsselskab for 1 864,two Speci e s of the genus of metridia ,
a l arger one that he cal l ed m. armata,and a smal l er on e , m .
Iucens. Mr . GIESBR ECHT has shown that m . armata m . longa,
Lubb .,and as for m . lucens, the said author is of Opinion that i t
can scarcely be classed to metridial
, because , according to Boncx,
i t l acks hooks on the first j o in t at the inner branch of the secon dpair of feet . It i s however l ik ely that m . lucens and m . hibern ica
are identical ; at any rate I have taken m. hibernica at severalplaces
,from Bergen to Lofoten . The north l imi t i s p ro tem . about
the 69th degree of lat . , most probably i t goes con s iderably furtherto the north . Accord ing to the rul es of p riori ty the name of hibernica should , I suppose , yi el d to that of lucens , but as the specieswas originally described so insuffici en tly , that it cannot be identified with certainty , i t may be right to k eep the term of hiberm
'
ca.
Whil e m . longa i s known from Greenland (A UB IV ILLIUS) , Spi tsbergen (GIESBR ECHT) , the Kara Sea (HAN SEN) , and has been tak enby myself at differen t places from Bergen to Tromso
,m. k iber
n ica has not as yet been found north of the arctic ci rcl e . Thefullgrown females of m . longa have a length of 4 mm .
'
or a l i ttl emore , whil e for the hibernica I can give the fol l ow ing measures
April 10th, 1897. Balstad in Lofoten .
0—200 (11 .
Q mm . , o" mm .
Nov. 24th, 1896 . Pud defj ord , near Bergen .
0—8 m .
Q Front body mm .
Hind
Nov . l oth,1 896 .
0—8 m .
of Front body mm .
HindM hibernica i s easily di stinguished from the longa by the
pointed corners at the last body - segment (fig . and by i ts com
paratively shorter furca , the breadth of the branches being abouthalf the l ength (fig .
Puddefjord .
mm .
Metrid ’ia longa, Lubbock .
The largest specimens of thi s species I took in the Ofoten .
fjord . The largest female measured mm . The mal e s had al ength of about mm .
fjords near Bergen , but the females here have scarcely exceededM . longa occurs at greater depths in the
4 mm . The largest one I have till now measured was mm .
H eterochceta norvegica, Boeck .
In Kristian ia Videnskabsselskabs F orhand linger for 1 872 , AXELBOECK has given a short diagnosi s of a copepod that he hadtaken at a rather great depth off the Norwegian coast
,and
which on examination was found to be of a sp ecies differingfrom the forms descr ibed by CLAUS (sp in ifi'
ons, papillige m) . Thesaid new species received the name of heterochaeta non
'
egica . GIBSUn
bestimmbare Sp eci es ” , at the sam e time stating that some of theBR ECHT
,in hi s wel l - known “Monographi e ” , has noted thi s as
characteri sti cs given suggest some known species . Boncx’
s descrip
ti on of 5th l eft foot of 07‘ does not however agree with any of thesp eci es prev iously described . The original de scripti on of h. nor
vegica i s as foll ows :“The upper feelers are not as long as the body . The basal
j o int of the outer j aw - foot i s armed with a strong thorn . Thefinal part i s di sti nctly separated . The first joint of the upp erfeel ers i s longer than the four others together . The outer branchof the second to fourth pai r of feet i s about three times as l ongas the inner branch . The final j o int i s very large
,oval
,suppl i ed
with three teeth in notches on the outer edge and at the point,
as wel l as near the l atter with three rough saw - teeth . In themales the basal j oint of the right fifth pair of feet i s drawn outinto a very large curbed hook . The second join t of the outerbranch ha s on the inner edge a knot . The third j oint i s drawn
In the l eft fifth pair of feet the th irdjoint o f the outer branch is Shorter than the second
,and inwardly
out into a strong point .
drawn out into a strong point,against w hich a curbed claw from
the point of the j oin t can strike ” . Thi s short description,which
is not accompan ied by drawings,i s certainly meant by the author
to be only a p rel iminary one . It i s seen from BoE cx’
s work
(“Nye Slegter 0 g Arter af Saltvand s Copepod er
”
) that i t was hi sinten ti on to deliv er an exten sive work on the copepods . Deathhowever abruptly put a stop to the real ization of thi s plan .
By examing a sample from the Ofoten—fj ord,taken Feb . 25th,
1897, depth 0—250 m .,I di scovered two specimens (Q , o
") of
23 .
heterochw ta which showed a rather great l ik eness to h. p ap illige m.
A closer inspection has p roved that the sp ecimens from the Ofotenfj ord differ , especially in the structure o f fifth pair of feet
,from
p apillfigera , whi le in al l es sen tial s th ey correspond with the descrip
tion of h. norvegica. The l atter will therefore,in my opinion
,
have to be maintained as a seperate speci es .Descr ipti on of Q .
mm .
Length . F
HindGreatest breadth 1 mm .
The front body consi sts of 5 segments,the two hinder ones
being j o ined into one . Of these th l and th4—5 are aboutequal ly broad , l ik ewise th2 and th3
,which however both are
narrower than the two former ones . (The terms of GIE SBRE CH T’
S
denotati on are here adop ted) . The head segment carri e s twoextremely small hairs , pointed forwards, and th e two rostralthreads . The brow papilla i s n ot pointed as in h. spinifrons , butbears an obviou s l ik eness to the corresponding one in h. papillige m.
The hind body (fig . 1 1) consi sts of four segments , dimini shingin l ength downwards ; the genital segment i s a l i ttl e longer thanthe three fol lowing taken together . The j oint connection betweenab s and furca i s rather indi stinct . The l ength of the furcalbranches i s not quite three times as great as the breadth
,the
l eft branch being a l i ttl e longer than the right one . Each furcalbranch carries 5 large bru shes and , bes ides , an extremely smallone on the inner side . One of the brushes on the l eft branch i smuch longer than the others . It was torn off b oth in the maleand the female
,but i t i s l ikely to be l onger than the body in
both of them . The piece that was l eft measured a l ittl e over 2mm .
,and at the fracture the thickness had not p erceivably de
creased . The geni tal segment i s on the v entral side very muchswoll en
,dorsally it has a peculiar inward curbing. Besides
,the
geni tal segment and the two foll owing ones carry on the dorsal sidea seri es of thorns (fig . In the former thi s thorny row
sits a l i ttl e above the l ower edge , in the two others i n the edgeitself. The first pai r af antennas con si st of 25 different pi eces
, (if
which the foremost one , which i s pointed forward , i s longer thanthe four fol lowing on es taken together . The l ength of the antennasi s mm .
,they are con sequently longer than the body , but as
the p roximal part i s sti ffly p rojecting , the antennas when foldedalong the body wi ll scarcely reach the end of the furca .
The posterior antennae which are fixed to a comparatively longhandle
,have two branches , of which the inner branch is somewhat
l onger than the outer branch . The inner branch i s made up oftwo j oin ts of which i l i s about three times as long as i ? (fig .
The inner branch i s made up of 8 j oints , the outermost of whichis l onger than the 4 fol lowing taken together (fig . The masticatory edge (fig. 2 1
,of the mandibl e has a characteri stic
armament,th ere being at one corner a curved tooth , at the other
corner three teeth,with one
,three
,and two points resp ectively ;
at the base of the last -mentioned point al so si ts a l ittl e brush .
The palp of the mandibl e con si sts of a short basal j oint and along one
,to whi ch are j oin ed two branches
,the outer branch being
broader than the inner one (fig. Both have feathery brushesat the top
,besides a l i ttl e feathery brush sitting at the second
basal join t. The maxilla are characterized by the inn er branch
(fig. 4) being very much reduced . The outer branch carrie s at theend 5 feathery brushes , and the reduced inner branch 3 extremelysmall ones . On one of the lobes of the basal part si t 5 verylong fea thery b rushes , and on the other a group of at least 10 such .
The firs t pair of maxil l iped s are characteri zed by a comparativelylong basal part, w hile the branches and lobes are very much re
duced . At the distal end there are two groups of l arge brushes ,three in each . In the upper group (fig. 7) the two are ben ttow ards the end and set w i th fine po ints that gi ve them a comblike appearance. In the other group two br ushes are equallylong and equally thick , while the thi rd i s thinner and scarcelyhalf the l ength of the two . The second pai r of maxi l l ipeds areconsiderably thinner in structure than the first pai r, especially thesecond basal j o int (bQ ) i s much p rotracted , the l ength being 5—6times the breadth . On the first bas al j o in t b l s its a very characteristic bru sh o r tho rn (fig . It i s curved and overlaps thedis tal end of b? . Besides there are at the end of b l two short
,
thin brushes and one th icker brush or thorn . Near the inner edgeof b ? is a row of smal l thorn s . The lowest of the brushes (1) ofthe uppermos t basal jo int s its a l ittl e above the middle of theinner edge of the jo int be. Altogether there are on the inner edgeof be 5 brushes . Of these (1) and (2) are smal ler than wich i sagain smal ler than The branch consi sts of 5 j o ints , decreasingin length toward s the end . Of these the 4 first join ts carry 3
brushes.In the first pai r of feet the inner branch is almost as broad
as the outer branch , and the length about of that of the outerbranch . The first pai r of feet i s shorter than the three fol lowing .
In the second pair of feet (fig . 8) the inn er branch i s not so longas the two lower joints of the outer branch , which is al so the casefor all the swimming feet 2—4 ; is i s about twice as l ong as i l ,and ya longer than y l y2 . In 3rd pair of feet ya i s comparatively longer and broader than in any of the others (fig. .
(There i s no perceivabl e difference in the structure af 3rd pair offeet in the two sexes) . 4th pai r of feet i s much l ike the 3rd ,though the poin t of y 3 short a somewhat d ifferent appearance
(fig . 5th pair of feet (fig . l ike the others, consi sts of twobranches , with 3 jo ints in each branch . The outer branch i sabout twice as long as the inner one ; y l l ack s bru shes, on y2s its a thi ck curbed thorn , with the curbing turned inward (proximal ly) . This thorn i s a l i ttl e longer than the inner branch . Onthe inner side of ya are four rather long feather- brushes ; the firstbrush i s about hal f as long as the jo int ya. Besides , ia has 6feather- brushes , and i ? has a thin , short brush , about half as longas the joi nt . A simil ar one sits on i l .
Apart from the comparative size , the femal e of h. norvegicashows great likeness to h. papilligera Q . The best di stinguishingmark I have found , is that the brushes on i f and i2 on the 5thfoot are cons iderably thinner and sho rter than the bru shes on ia.
By the thin and short brushes on the two lower joints of the inn erbranch , h. nomegica shows a l ikeness to h. clausii, Giesbrecht .From the latter, however, h. now egica i s di stingui shed by lackingthe thorn - like brush on y l . Besides i t may be noted that inh. claw ii the curbed thorn on y2 i s shorter than the inner
branch,while the final brush on ya i s more than hal f the l ength
of the jo i nt .
Length
H . norveg icaFron t body mm .
Hind
Totall st pair o f antenna mm. , consequently longer than the
body . Greatest breadth mm . The long furcal b ru sh was tornoff, but the piece that was l eft measured a li ttl e over 2 mm .
,so it
i s likely that i t i s longer than the body .
The anterior l eft antenna i s tran sformed into a clutching an
tenna. and i s di s tingui shed from the corresponding one in the femaleby several jo ints towards the distal end beingjo ined in to one (fig .
The segmentation of cephalo- thorax i s like that i n the femal e,
the hind body on the contrary consi sting of 5 j o in ts , of which the4 uppermost have a row of smal l thorns at the binder edge of thedorsal sid e (fig . In the structure of the jo i nted organ s of thebody there i s great l ikeness between the two sexes , only in resp ectof 5th pair of feet the l ikeness i s l ack ing. The second basal jo intin the right 5th foot has a characteri sti c p roj ecting formation thati s bent inwards towards th e j oin t (fig . 20
, y2 has a knottedproj ection on the inner side ; y3 , which is of a l engthened andvaulted form
,i s suppl i ed with 3 brushes , of which one short and
thick and one longer and thinner si t at the point of the joi nt, thethird i s on the under side o f the joint . The lowest j o in t of theinner branch i s rather short, and the connection between it andthe following one i s obl ique , compared to the l ongitud inal direction ;i l l acks brushes
,i2 has 1 and is 6 .
The l ength of y3 i s about as y l y 2 .
Especially characteristic of l eft foot i s the joint y3 (fig .
BOECK says about it :“Third j oin t of the outer branch i s shorter than the second
,
and inwardly drawn out into a strong poin t,against which a curbed
claw from the point of the j o int can strike” .
It i s mos t l ikely that i t i s h. now egica I have found , but inthat case BOE CK ’
s description i s not qui te correct . On the joint
ya are 3 brushy proj ections . Of these the two short ones (s , t,)di stinctly articulate wi th the j o int
,whereas the articulation between
f and y3 i s indistinct .Fifth pair of feet in the male shows an astonishing l ikeness
to the corresponding one in h. abyssalis , about whose appearancethe excel len t drawings of Gm snas cn
'r give suffici ent i nformation
(Monographie , Taf. 20 , fig . 29, However , the knotted projection on y2 of fifth right foot seems to be relatively small er in h.
norvegica than in h. abyssalis ; the thin final brush i s in aw rvegica
shorter,fo rming about Vs of the length of the jo int (ya), whil e
i n abyssalis i t i s more than hal f the l ength of the jo in t. Whatchi efly seems to distinguish the two specie s i s the appearance of
ya in l eft fifth foot,the brushy proj ection f in norveg ica being
d istinctly projected from the jo int, whil e in abyssalis they runtogether with no defini te l imi ts . Fifth pair of feet in the mal efurther shows a distinct difference from the corresponding on e inthe M edi terranean forms.
Id l/Il fureuta . Bai rd .
Box-20x states that the speci es i s common everyw here along theshore . I have seen it in plancton sample s from the l i ttl e fjordouts ide the B iological Stat ion .
Conclaoccia clegmw . G . O . Sars .
(Oversigt af Norges marine Ostracoder, p . 1 17—1 18. K ri stian iaViden . Selsk . F orh. 1865 . The diagnose in La t in) .
Ost racods have appeared in a few cases in the samples I haveexamined . Thus the above form occurred in a sample from 0—100111
,
taken March 26th, 1896 , 8 mil es S . E . to E . of the fishingstation Reine i Lofoten .
m hoecia obtusata. G . O . Sars .L . c .
,p . 1 18—1 19.
Of this species I found two sp ecimens in a sampl e from aboutthe same place (Mar . 23rd , 1896 , 1 6 mil es S . E . to E . off Rein e
,
0—1 30
Evadne nordmanni, Loven .
At certain times the evadne i s one of the commonest forms ofthe plancton . Thus in June 1897 the speci es occurred in greatquantity outside the Biological Sta t i on .
Podon polyphemoides, Leuckart.
In the l i ttl e fj ord on which the Biol ogical Stati on i s si tuated,
podon in 1897 occurred most frequently in the month of July .
Podon,as well as evadne , are by G . O . Sans gi ven among the
species that serve as food to the sprat .
Parathemisto oblivia ,Kroyer.
Thi s arctic form I hav e observed at different places in theplancton
,and also in the stomach contents o f gadus callm'ias and
y. z‘irens . In stomach s of the latter species (Sundern i n Vester
aal en,Feb . 1897) I al so took the forms far more rare on the
coasts of Nor way,of euthmnisto comp ressa, Go
‘e‘ s , and c uthcmisto
bisp inosa, Boeck .
Amathilla homari, Fahr .(A . sabim i, Leach) .
Fry and young i ndividual s of thi s amphipod occurred in thesurface at Sundero in Vesteraalen, Feb . 10th, 1 897. Sans state sthat the sp ecie s occurs in comparatively shal low w ater among algaefrom Kri stiania - fjord to Vadso. Among other amphipod s observed
26
i n the plancton may be mentioned monoculodes tesscllatus, Schneider ,taken in the Tromso sound (Apri l 2 0th, 1897) in a surface sample .
Boreophausia inerm is, Kroyer.
This schi zopod,w hich w as sometimes found in great quantity
in the stomach of the Lofoten cod,al so appeared in the plancton
samples . In the O stnes - fj ord , Lofoten , al so thysanoé'
ssa neglecta,Kroyer, was found whereas I have not ye t obtained nyctiphanes
norvegica i n the plancton net , but have seen thi s specie s i n greatnumbers in the stomach of gadus rirmzs . Besides the three ephausidae mention ed , the fol lowing belong to our fauna
Euphausia pellucida, Dana .
Borcophausia raschi i, M . Sars .Thysanoe
'
ssa longicaudata, Kroyer.
Pseudocuma cercaria,v . Beneden .
Of this cumace which must probably be noted as a southernform
,I took in a plancton catch on Feb . 22th, 1897, a singl e
Specimen , in the harbour of Brettesnes , Lofoten . Along the northern coasts the sp eci es i s l ik ely to be rare . SCHNEIDER statesthat he has taken a specimen at H illeso in Malangen -fiord .
In . some of the plancton samples that I have examined , Ihave been struck by the number of foramini fera that occurred .
The only explanation seems to be that a great d eal of bottomforms are w hirl ed up by the current and are kept floating forsome time . Mr . HANS Kmart of Kri sti ania has shown me thekindness of defin ing th e foramin ifera in some of the sampl es takenduring my journey in 1897, and the resul t i s here given from hi smanuscriptMarch 1 1th, 1 897. mil es SSE of Ure in Lofoten .
Planorbulina lobatula, Walk 8: Jacob , a few specimensCas sidul ina crassa , d
’
Orb. ,
H apIOphragminm nanum ,Brady one smal l
March sth, 1 897. s. to w . off Vater- fjord , 0—1 00 (O stnes - fjord) .Nonionina scapha , Ficht Moll on e defective specimenPlanorbulina lobatula, Walk Jacob , someUv igerina angulosa , Will ,Pulvinulina punctulata , d
’
Orb. ,
Cassidul ina laevigata , d’
Orb.
,
Verneuilina polystropha, v . Reu ssApri l 20th 1897. Tromso- sound , plancton from surface .
Polystomella striatOpunctata, Park Jones,2 sp ecimens .
March 1 1th, 1897, Gimso- strommen,pl ancton 0—50 m .
Planorbulina lobatula, Walk Jacob,some spec imens
refulgens , d’
orb . ,
akneriana, d’
Orb. ,
Miliolina seminulum , Lin . ,
Feb . 9th,1897. Sundero , Vesteraalen , in p lancton taken from
the beach .
Planorbulina lobatula, Walk Jacob,one specimen .
Apri l 30th, 1897. Rest. Plancton taken in the surface at thequay of Glea.
Planorbulina refulgens , d’
Orb. ,
lobatula , W' alk Jacob ,
coronata,Park Jones
,
many specimen s
akneriana , d’
Orb. ,
Uvigerina angulosa , W'
i l l .,
Cassidul ina laevigata,d
’
Orb.
,
Globigeri na bulloides , d’
orb .
,
Operculina ammonoid es , Gronov ,Polystommella striatopunctata , Park Jones , two
0 118
Uvigerina pygmaea , d’
Orb.
,
Bullimina marginata , d'
Orb.
,
Haplophragmium canari ense , d’
Orb.,
glomeratum ,Brady ,
Miliolina seminulum ,Lin .
,
Nonionina d epressula, “T alk 8; Jacob ,
stelligera, d’
Orb.
,
Textularia w illiamsoni, Goes , som ePulvinulina concentr ica , Park Jones
March,5th, 1897. O stnes - fjord , Lofoten .
Planorbulina lobatula , Walk 8; Jacob ,i
‘
efulgens , d'
Orb.
,
Plancton from 0—60 m .
many specimens
akneriana , d’
Orb. ,
Operculina ammonoid es , Gronow ,Discorbina globularis , d
'
Orb. ,
Cassidulina laevigata,d
'
Orb.
,
Nonionina depressula , Walk Jacob .
Miliolina semigumum,Lin . ,
Apri l 28th 1 897, O m .
, Rust.
Planorbulina lobatula,
Jacob,
refulgens , d'
Urb
many Specimens
coronata Park Jones,
akneriana , d'
Orb.,
Uvigerina pygmaeaangulosa
,\Vill . ,
Polymorphina compressa , d’
Orb
Cassidulina laevigata,d
'
Orb
Globigerina bulloid es , d’
Orb ,
Nonionina depressula , \Valk 8; Jacob ,H apIOpbragmium nanum ,
Brady,
Pulvinulina concentrica,Park Jones
Discorbina obtusa , d'
Orb. .
Lagena lucida , Wil l . var . nordgaard i, n . v . two
Descrip tion of the new var .
Py r i f o rm i s a u t o v a l i s , v i x c o m p r e s s a , o b t u s e m ar
g inata , utrin q u e c o s t a l a t a p raed ita , e n to s o l e r n ic a ,
a p e r t u r a o v a l i s m ag n a . L o n g . mm .
27
At the present stage of my investigati ons of animal planctonat our coasts
,i t i s impossibl e to give any general description .
What has t il l now been done in thi s field must rather be . said tobe of a reconnoitering
‘kind . I have tried to obtain knowledge ofthe forms , their hori z ontal and verti cal distribution , but have til lnow undertaken no quantitative plancton determin ations . Of courseI hav e seen that there i s great difference in the quantity of animalplancton in th e months of September and February . for in stance .
In Lofoten i t i s rather poor i n the latter month,especially in the
surface strata,as i s also the case in the fj ord s near Bergen . Both
animal and vegetabl e plancton , however, i s found al so in the monthof February . Arctic cop epods
,as metrid ia longa, euchaeta nort
'
egica,‘
and calanus hyp erboreus, I have scarcely ever taken in the surfacestrata (U—aObeen about 6" O ,
and the saltness —35 m . Zonga and c.
hyperboreus have occurred in greater numbers , especial ly in Lofoten .
But in the deep,where the temperature has
Near Bergen too,I have ob served a few sp ecimen s of the above ;
mentioned arctic copepods . Recently there occurred further afemale of heterochw ta norz
'
egica (By- fjord,Aug . 24th
,1 897
,0—300
The occu rrence of arctic coliepod s in our waters can scarcelybe used to suppo rt the so call ed "curren t hypothesis ’
. I t i s l ikelythatdeep of the fj ords because arcti c conditions are p revail ing there .
d r . HJORT i s right in saying that these animal s occur in the
Throu It a seal - hunte r at Tromso I have obtain ed someg
plancton samples from the sea between Norway and Spitsbergen,
the summer season . In some of these occur greatAt our
coast,however
,I have
,as mentioned above
,hitherto only taken
taken in
numbers of calanus hyperboreus from the surface strata .
this species in somew hat deeper water . What appears particularlycharacteristic of arctic condi ti ons
,i s the great uni formi ty throughout
the year of temperature and saltness,and i t i s therefore l ikely
that tbc arctic animal forms occurring in our waters keep in thedeep
,because the physical cond ition s there. are most corresponding
to those of the Arctic Ocean .
I thus think I have observed,in the case o f several arctic
copepods,that in our waters they are chiefly boun d to the deep
,
and thi s circum stance may be one of the cond i tion s that cause thei r
Thi s n ice form i s pear - shaped or oval,and scarcely compressed
from the sides , the keel i s obtuse and has on either sid e a paral lelrunning , thick ened strip e , w hich ends above in a rounded point ata di stance of about One third of the l ength of the shel l from themouth - open ing ; below i t i s somewhat bent upwards and somewhatnarrow ed by the button - shaped thickening that the shel l ends in .
Thi s strip e is by transparent l ight dark , by surface light it i swhi te , the el evati on of i t being quite smal l . At. the mou th theshel l i s squarely cut off
, at the lower end i t i s drawn out into anobtuse prolongati on . The species reminds one very much of l .
quadricostata , Reuss , but i s di stingui shed from the l atter specie s bythe form of the strip es
,the almost ball - shaped shell
,and by the
oblong aperture , w hich i s poin ted to both sides .Two specimen s were found by Mr . O . NOR DGA A R D at Rost in
Lofoten , and w ere call ed after him ’
.
i nferiority in number, s ize . &c . On account of the importance ofl ight to the vegetable plancton world , the quantity of food , insummer at any rate. w il l be greatest in the surface strata ; cousequently a certain species will here find the best conditions of l ife
,
i f the stay there i s not rend ered impossibl e by the physical conditions. In this connection I shoul d also mention that for in stancecal mus hyperboreus from the su rface of the sea at Jan Mayn hadvery red coloured antennae, whi l e those o f specimen s from Bergenand Lofoten were colourl ess .
The arcti c copepods , c. hyperborw s, metrid ia longa, e uchazta
non vegica . heterochw ta norvegica ,seem to occur at our coast through
out the year, and the i r occurrence need not at al l b e dep enden ton tran sportation by arctic currents . When , on the contrary , suchanimal s a s 0150 (m a ths and limacina hel -ieina, on rare occasionsoccur in our waters (according to statements by BOECK and Sans) ,it seems to me to support the Opinion that some times arcti c currents force thei r w ay up to our coasts .
I have mentioned above that the winter pl ancton i s ratherpoor . There may , however, even i n the month of February inLofoten occur rather many forms . As an i nstance of thi s
,I give
a l ist of the contents of the samples from Liland (Ofoten - fj ord)and Tjeldsnndet. The d iatomaceze , dinoflagel lata, tintinnodea, &c.
have been determined by Mr. Jonons ss s of Bergen .
Li land,
Febr. 24th 1897.
0—300 m .
Tjeld snnd et,
Febr. 24th 1897.
0—200 m .
Copepoda.
Galenus finmarchicns , Gunn .
hyperboreus,Kreyer
Metrid ia l onga , Lnbl)Enchteta norvegica , BoeckOithona simil i s, ClansMicrosetella atlan tica , BradyLarva: of copepodsChaatognatha
Diatomacesa.
Chaztoceros boreal e , Bailcriophilnm,
Castr.
decipi en s Cl .diadema
, (Ehrb.) GranCoscinodi scus radiatus , Ehrb
oculus i ridi s , Ehrbconcinnns, W . Sm .
Striatella nnipnnctata, AgSkeletonema costatum (Grev .) Cl .
Thuretn , BrebNavicnla latissima GregThalassiothrix l ongis sima , Cl .
Dinoflagellata.
Ceratium tripos , (O . F . Mttll .) Nitz sch .
v . bucephalus Cl .
v . macroceros , (Ehrb.) Clap. et Lachm.
v . arcticus , (Ehrb.) Clap . et Lachm.
C . fusns (Ehrb.) DnjC. furca , (Ehrb.) Dui.
Perid in ium divergens , Ehrb.
pel lucidum , (Bergh) Schittt.Gonyaulax spinifera, (Clap . et Lachm.)
D i es .DinOphysis norvegica, Clap. et Lachm .
acnta, Ehrb.
Tintinnodea.
Amphorella subulata , (Ehrb.) Dad . .
Tintinnopsis n itida , Brandtheroides
,Stein
Cyttarocylis denticulata , (Clap etLachmFol .
v . edentata , (Brandt)v . rotundata n . v .
Ptychocylis nrnnla, (Clap . et Lachm.)Brandt
0 0 0 0 0 0 0 0 0 0 0 0
The sign s above,as w el l as in the tabl es
,have the fol lowing
signification
After the above w as i n the hands of the printer, I had anopportuni ty of seeing the great work of dr. VA N H oF F EN on “D i eFaun a und Flora I see there that VAN H OF F E N inKarajak- fj ord has found the male of calanus hyperboreus as wel l asthe male (one specimen) of hetcrochazta norvegica. The total l engthof the l atter was mm .
, i t was consequently a l i ttl e bigger thanmy specimen . VA N BtSF F EN al so emphasize s the l ikeness wi th h. abys
sal'is, Giesb. I am,however
,incl ined to suppose them to be two
different species and I al so suppose that the identity of the h.
spinifi'
o'ns described by BR ADY and h. norvegica, cannot be main
tained with certainty .
Gron land a-Exped i tion d er Gesellschaft fur Erd kund e z u Berl in , 18911893 , unter Lei tung v on Erich von Drygalsk i .
cod season . And that a considerable d itlerence in the year ’s number of cod - ind i viduals fit for propagation exercises a perceptibl einfluence on the prod uce of the w in te r fishe ri es, must be consideredmos t probable. A red uction of the number of the cods of theseason that are fit for propagation , may of course in part be causedby unfavourable physical condi ti on s du ring the fry stages , (in an alogy with the unfavourabl e influence of sev ere frost on the younggrouse) , but at present not very much can be said about th i s matter.
30
In the present work I have tri ed , wi th a good will and atthe best of my abil i ty , to draw reasonabl e conclusions from theobservation s of others as wel l a s my own . In certain po i nts myv iews differ from those of prev ious authors . It may be that I hav econcluded more than the observ ation s allow of, or that I have even
judged of facts in a wrong way . It i s however my hOpe that th ematerial of observations I have brought forward wil l prove usefulfor future inv estigations .
Exp l an a t i o n o f the Pl a t e.
H . n .
C . h.
C . f.
M . h .
heterochaeta norvegica.
calanas hyperboreus .
finmarcliicus.
m etrid ia hibernica.
yi , y 2 , y3 jo in ts of the outer branch of feet .ii
,is
, is innerbi , M basal joints of fee t and max il l iped s .
proximal j oints of anterior antenna mal e .
y1 , y2 , foot of fifth pai r,female
foot of fifth pair,female
maxill a , female
cephalothorax and abdomen,male .
distal jo ints of anterior antenna,male .
maxill iped of l st pair,female
foot of 2d pair,female
maxi ll iped of 2d pair,male
posterior antenna of female
abdomen of female .
foot of 3d pair , male
foot of ath pair,l eft s ide
,male
maxil l iped of 2d pair,female
foot o f 5th pair,l eft sid e
,male 1 00 ’
the dentition curve on the basal j oin t of the
same
1 7. foot of 5th pai r , right side , mal e
18 . C . h., cephalothorax and abdomen male lateral vi ew H . n
y3 , foot o f 4th pair , femal e
foot of 5th pair , right side , male
mandible of female
y3 , foot of 5th pair , l eft side , male
the cutting edge of the mandible (mandibel
lade) , female
the inner branch of poster ior antenna,female
abdomen of female,dorsal v iew
the last j oint of cephalothorax,female
,l a
teral v iew
the dentition curve on the basal joint of the
foot of 5th pai r, female
the d ention on the basal joint of the foot of
5th pair,femal e
foot of 5th pai r , r ight side , male
the dentiti on curve on the basal j o int of the
l eft foot o f 5th pai r,male
foot of 5th pai r,l eft side
,male
foot of 5th pair , right s ide , male