entanglement studies, st. paul island, 1989: juvenile male ... · this report presents the resulfs...

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ENTÀI{GLEMENT STUDTES, ST PAUL TSL,AND, 1989

JIIVENILE MALE NORTHERN FUR SEALS

Charles !{. Fow1erl

and

Timothy J. Ragenz

lNational Marine Mammal LaboratoryAlaska Fisheries Science Center

National oceanic and Atmospheric Adrninistration7600 Sand Point !{ay N.E., Bin C15700

Seattle, f{ashington 99115-OO7O

2craduate Studies Office, A-OO8Scripps Institution of OceanographyUniversity of California, San-Diägo

La Jolla, California 92099

May 30, 1990

ENTÀ¡{GLEMENT STUDIES, ST PAUL TSLAND, L989

JWENILE MALE NORTHERN FUR SEALS

by

Charles !{. Fowler and Timothy J. Ragen

INTRODUCTION

Entanglement in marine debris, specifically in plasticsassociated with the commercial fishing indusÈry, has been

documented for a number of species of seals and sea lions (Fow1er

1988). The effects of entanglement in such debris have been thesubject of a number of studies, especially as rerated. t,o theinpact on northern fur seals (callorhinus ursj.nus). Many ofthese studies have examined effecÈs at Èhe population level(Fowrer 1982, 1985, L9B7). others have studied the effects atthe level of the individual (see Fowler 1989).

Northern fur seals (Callorhinus ursinus) become entangled inplastic debris and scraps of fishing nets as they forage in theopen ocean. such entanglement, especiatly in scraps of net, is a

source of mortality for this species and has been the focus ofresearch examining recent declines in the northern fur sealpopulation on the Pribilof rslands (Fowler 1997). A number ofrecent studies conducted by the National Marine Mamma1 Laboratoryhave focused on the effects of entanglement in narine debris on

northern fur sears (Bengtson et al. 19gg; Fowler 19g4, LgBs,

L987; Fowler et aI. 1999, L990, in press).

Juvenile males (aged 2 Eo 5 years) frorn st. paur rsrand,Alaska, are the component of the population most readily studied.

2

Entanglement among these males is studied during roundups (as

described in more detail below). This report presents theresulfs of the L989 field research conducted by the NationalMarine Mammal Laboratory to examj.ne entanglernent and its irnpact

on male northern fur seals.

The objectives of this work are: (1) continued monitoring ofthe proporÈion of sears enÈangred, (2) determination of thenature of entangling debris, (3) deteraination of the rnortalitycaused by trawl webbing, especially as related to effects at thepopulation level, and (4) assessment of the reraÈive rates atwhich entangred and contror animals are resighted. part of Èhe

study of relative rates of resighting addresses the question ofwhether or not an animalrs chances of being seen again arealtered by beingr or having .been, entangled..

METHODS

The studies reported here involved roundups, a procedure

conducted on st. paul rsland, Alaska near breeding coronies ofnorthern fur seals. All work hras conducted during the breedingseason of this species, whire aninars erere congregated at, ornear, breeding rookeries arong the shoreline of the island.

During roundups, young mares are herded together to be

examined for debris or tags and for apprying tags. To conduct a

roundup, fierd biorogists approach a hauling ground near a

breeding rookery where young males come ashore in 1arge numbers.

Avoiding disturbance to the rookeries, the members of the

3

research tearn posit,ion themselves between the hauling ground and.

the water. The males on Èhe hauling ground are then surrounded

and herded together away from the rookery but close to the

waterrs edge. Care is taken to ¡nininize the movement required ofthe animals and to allow them sufficient space to prevent

crowding and overheating.

Once the seaLs are in a conÈrolIed group, field workers then

allow small numbers of animals to leave the group and file toward

the water. Once one or more seals begin rnoving toward the water,other seals follow. This movemenÈ is controlled (to ensure thattagged flippers will be seen) by the field cre$r. t{hile moving

toward the water, seals pass between obsernrers, some of whom are

engaged in counting seals whire others watch for tags and

entangling debris. others of the field crew remain prepared tocapture seals, while the remainder work to assure Èhat Èhe main

group of sears remains in prace. By the end of the roundup, ar1

seals have returned to the water. Most seals, handred or not,return directly to the water.

The seals counted are those judged to be of the sizehistorÍcally taken in the commercíal han¡est (approximately 105

to L25 cm in total tength). Unless indicated othersise, data inthis report apply to seals of this size. The total count and thecount of entangled animals are used to estimate the entanglementrate for comparison with rates observed in the commercial han¡estprior to 1985. À11 entangled seals small enough to safely handlewere captured and freed of the debris.

4

when an entangled or tagged sear is seen among those

leaving, the movement of seals from the main group is stopped.

rf t,ag numbers cannot be read, if tags are to be applied, or if a

detailed examination of the debrÍs is required, the sear iscaptured with a wooden pole fitted with a rope noose (Iess than

2z of Èhese sears escape to the water wÍthout being captured).rf tags are to be applied, or the debris examined in detail, theseal is praced on a restrainÈ board (Gentry and Holt Lggz) for a

few minutes. Tags are applied on the inner trailing ed,ge of each

fore flipper, about 2-3 cn distal from the hair line accord,ing tostandard practice for this species (Gentry and Hort 1992).

rf the captured animal is entangled, Èhe nature of theentangrement is recorded (and tags appried if not previousrytagged), and the debris is'removed. Data recorded at the tine oftagging include the tag nu¡nber and the extenÈ of the wound thedebris has caused. The coror, size (weighÈ), and type of debris,and mesh and twine size if it is a net fragment, are determinedfor each pÍece of debris. Sanples are retained for analysis toidentify plastics.

Two control seals about the same size as the entangledaninal are also tagged Èo compare rates of return in succeedingyears. The choice of tagging two conÈrol seals is arbitrary.Tagging more conÈrols than entangled sears ensures a rargersampre of returns to be used in comparing the relative rat,es of

5

return of the two groups. It also aids in the study of the

frequency of resighting rates and the locaÈions (for study ofintermixture) of resighted seals.

Some of the animals seen in the first roundup are seen again

in later roundups. The resulting sampling: scheme is one ofsampring with repracernent, and the data for both the controranimals and the entangled animals are treated accordingly.

RESULTS

Roundups

SÍxty-five roundups of male northern fur seals were

compreted on st. Paul rsrand during July 1999 (Table 1). During

thêse roundups, 18rs65 male seals judged to be of the sizehistoricarry taken in the commercial ha:r¡est were counted. Às

wirl be exprained below, about 25t of each of the total counts(unentangled and entangted) r¡/ere repeated sightings. fn all, 43

entangled subadult nale seals judged to be of harr¡estable sizewere captured and double tagged with numbered orange À1lfIex1tags bearing the address of the National Marine Mammal Laboratory(Table 2). Following experimentar procedures from previousyears, Èwo controls per entangled sear hrere also tagged tocompare rates of return in succeeding years (Table 2). A totarof 86 simirarly sized contror seals with no entangring debrishrere tagged.

lReference to trade names does not irnply endorsement by theNational Marine Fisheries Sen¡ice, NoAÀ.

6

Tagged Seals frorn Previous years

Seals Èagged in previous years were resighted (Table 3)

along with sears tagged during the 1989 season. As in previousyears, some of the seals tagged in L9g9 were seen on more than

one occasion. of the resighted seals for which the tags vrere

read, 68 had Allflex tags from 1995, L996, and 1988 duringearlier phases of research to evaruate the mortality of young

male seals entangled in debris. Fifty-nine of Èhe 68 resightedseals vrere tagged in previous years as contrors. Nine had been

entangred when tagged. of the 9 sears resighted after having

been tagged as entangled, 4 had lost their entangling debris.Three pieces of debris that were lost had been noted at Èheirfirst sighting as being smarl (o-lso çt in estinrated weight) and

one $ras medium (150-500 g). Three additional tagged seals fromprevious years (Èwo with orange Allflex and one wiÈh whiteAllflex tags) were sighted but the tags were not read; none ofthese animals were entangled at the time of the resighting (i.e.they were either conÈrols or entangled seals that had lost theirdebris) .

Entanglement Rate

I{e examined forty-seven entangred juvenile mare sealsencountered in the 1989 roundups (the 43 seals mentioned above

and 4 that stere judged to be larger than historically harrrested)to remove and determíne the nature of their enÈangring debris.

7

The size and kind of entangling debris, the extent of any wound,s,

and the tightness of the entangling debris on the animal arepresented in Tabre 4. A key to the tags applied during the t-989

field season is provided in Table Z.

For the ent,angled sears examined (47) , 19 (38.3å) carriedfragrments of trawl webbing, 15 (31.9t) ptastic packing bands, and

9 (19.1t) string, small rine or cords. The remainder (5 or10.6*) were entangled in other debris. The overall entanglement

rate is estimated by the ratio of alr (both initiar and arIsubseguent) entanglement sightings to the total number of sealsexamined (Bengtson et aI. L9gg, Fowrer et al. in press). rn 1989

this sarnpring design included the resighÈing of animars fromwhich the debris was removed during the same season but whichvtere counted as entangled. rn all, there srere s6 seals (the 43

from above with Èheir repeated sightings) seals of ha:r¡establesize obsen¡ed entangled. The entanglement rate for 19g9 v¡as thus0.302t (56118565). The 1999 rate of entangrement is Ìess thanthe obsen¡ed rate of about 0.4* between L976 and 19g5 (Fig. 1,

Fowler et a1. 1990). The majority of the reductj.on can be

attributed to a reduction in the rate of entanglement in trawlwebbing (Table s). HistoricaJ.ry, the rate of entanglement intrawl webbing has been about o.2z* (Fowrer et ar. 1990). rn 1989

that rate dropped to about 0.159, a reduction to about s6z ofearlier levels (Fowler et al. 1990). In 19g9 this rate remainedlow, at about O.L2Z (Table S).

I

Resightings and Sulr¡ival

Table 6 shows the record of tags applied to juvenile males

during entanglement sÈudies for each year since 1985. No samples

$tere collected in L987. À total of 156 tagged seals judged to be

of han¡estable size vtere tagged and released in 1988 ì 52 of these

lvere entangled. rn 1989, 20 (19.22) of these seals, originallytagged as conÈroIs, !ìrere resighted (Table 6). Five (9.64) of theseals tagged as entangled animals in 1988 vrere resighted in 1989

(Table 6). This inplies a resighting rate of seals tagged as

entangled in previous years of about 50* of the rate for controls(9.6/L9.2 = 0.5). AlÈhough not significantly different from a

ratio of 1.0 (chi-sguare test, p ) o.o5), the difference inratios for 1988 and 1989 is consistent with the sutr¡ival rate(about 0.5) estinaÈed for the effects of entanglemenÈ in srnall

debris (Fowler eÈ al. in press).

rn 1989, 32 of 279 seals tagged as contrors in L9g6 srere

resighted. Four were resighted out of a group of r2B animars

tagged as entangred in 1996. The resighting rates are 1L.5å and

3.18, for their respective groups and are significantly different(Chi-sçrare test, p ( O.OS).

No animals tagged as entangled in 1995 were resighted inL989; however, eight controLs from L9g5 vrere resighted. This isa significant change from the original ratio of tagged entangledseals to controls for that year (Table 6).

9

As reviewed above, the data for relative resighting rates ofseals Èagged in 1985, 1986, and 19Bg and seen in L9g9 are shown

in Figure 2 along with the data from previous work reported, inFowler et al. (in press). As described above and as can be seen

in Figurè 2, the 1999 data are consistent with the results ofearlier work (Fowler eÈ aL. in press). The cumulative datacontinue to show estimated annuar sun¡ival of 0.5 for sealsentangled in s¡narl debris, independent of alr other sources ofnortality.

Characteristics of Entangling DebrisBecause the debris was removed fron the entangled seals in

1989, it was possible to dírectly detemine weights of thedebris. The size frequency distribution of the fragments oftrawl webbing on seals is shown in Figure 3 for d,ebris weightsand in Figure 4 for mesh size. Specific weights and mesh sizesare listed in Table 4. These distributions are very sinilar tothose seen for debris fron entangled northern fur sears inprevious studies (Fowler 1987). Slightly over 70å of the debrisfound on seals (seals seen entangled for the firsÈ tirne) weighed.

between 0 and 150 q (Table 7). AbouÈ 2oz of the debris weighedbetween 150 and 5oo g. Àbout log of the debris weighed over5o0 g. The rates of return for seals entangled in debris of thethree size categories dÍffered markedly. Approxinately harf as

nany seals entangled in nedium sized debris vrere resightedcompared to seals entangled in the smarler debris (Table B). The

10

reÈurn rate drops again by nearly soz for seals in heavy (over

500 g) debris compared to seals in debris of the intermediate

category. Thus, it is seen that ¡nortality rates increase withsize of debris.

Within Season Resighting Rate

The fraction of seals tagged as entangled seals and

resighted in the same fierd season was about the same as forcontrorsr âs seen in previous work (Fowler et al. 1990). This

resighted fraction is close to zsz for alr years. There is no

statistically significant difference in the rates of resightingbetween the two groups (Chi-sguare = 0.805).

DISCUSSTON

Entanglement related field studies of juvenile male northernfur sears in 1989 vrere different from earlier years in thaÈ

debris was removed from entangled animals. Accounting for thisdj.fference through counting the resighted, entangled anj.mals withdebris removed, the entanglement raÈe continues to show thereduced levels obserr¡ed in 1988. À second year of reduced ratesprovides more convincing evidence that a change has occurred inthe entangrement rates, especialry since it continues to be

attributable to a reduction in entanglement in trawl webbing. An

explanation for such a change can not be conclusively establishedat this time. However, the differences between the 19g8-g9 ratesof entangrenent and those of previous years may be a resurt of

t1

changes in the rate of loss and discard of net fragrments.

Various education programs at national and international levelshave been in place for severar years and internationalregulations prohibiÈ Èhe discard of such debris. Other studieswould be necessary to determine if reductions have occurred inthe rate at which debris is entering the narine environment.

ResulÈs of the 1989 studies are consistent with those ofearrj.er work in showing that some animals escape from theirentangling debris. This appears to be one mechanism contributingto surr¡ival from entanglement. However, as documented in Fowleret aL. (in press), Èhe ani¡nars that lose their debris arepredominantly seals entangled in snall debris (less than 150 g).This, in combination with data showing that nortality increaseswith Èhe size of debris (Table B), continues to ernphasize thefact that there is mortality beyond that estimated with data fromstudies of the seals seen on land.

SUI,ÍMARY

Entanglement research on juvenile mares in 19g9

demonstrated:

1) A continued reductj.on of the overallfrom about 0.4t (1925-86) to about

1989.

entanglement raÈe

0.33 in 19Bg and

2) Entanglement Ín trawr webbing in 1989 was about half ofentanglement levels obserr¡ed for this kind of debris in

L2

previous years (1-981 to i.988) and very sinitar to therate observed in 1999.

3) The rate of resighting for animals Èagged in L9g6 showed.

Èhat entangred anirnals tagged in that year were seen ata rate that was significantly less than that forcontrols.

4) Data for relative return rates of entangled seals (insmall debris) continued to produce an esti¡nated

surrrival rate independenÈ of natural causes ofnortality of about 0.5 per year.

5) There is further evidence from the 1989 studies that therate of return of sears enÈangled in heavier debris isless than for seals in lighter debris.

ACKNO!{LEDGMENTS

The research reported herein vras partially funded by theNational Marine Fisheries Sen¡ice Marine Entanglement program,

James coe, program Manager. !{e would rike to thank NorÍhisaBaba, Bruce Fowrer, Floyd Fowler, Mike Grenn, Masashi Kiyota,Rolf Ream, and f{illia¡n (Bud) smithey as members of the roundupcrest for L989. The help of groups such as this have been crucialto the production of the data on fur sear entangrernent. JasonBaker is to be credited for weighing the extremely foul smellingfragments of debris removed from the seals in 1999. we

13

gratefully acknowledge reviews of this paper by Kara Amundson,

George Antonelis, Howard Braham, Laurie Briggs, James Coe, Gary

Duker, Sharon Giese, Hiro Kajimura, Tom Loughlin, and Ralph

Svrjcek.

L4

REFERENCES

Bengtson, J. L., C. W. Fowler, H. Kajimura, R. Merrick,s. Nomura, and K. yoshida. 1999. Fur seal entanglement

studies: Juvenile rnales and newly-weaned pups, st. paul

rsrand, Àlaska. rn: p. Kozroff and H. Kajimura (editors),Fur seal rnvestigations, L995, p. 34-sz. u.s. Dep. commer.,

NOAÀ Tech. Memo. NI4FS F/NWC-146.

Fowler, c. w. 1984. EnÈanglement in fishing debris as acontribuÈing factor in the decline of northern fur seals on

the Pribilof Islands. NatI. Mar. Mamural Lab., Northwest and

Alaska Fish. cent., Natr. Mar. Fish. serv., NOAA, seattle,wA 98115, 33 p. (Background paper submiÈted to the 27tjin

Ànnual Meeting of the Standing Scientific Cornnittee of theNorth Pacific Fur seal comnission, 9-13 epril 1994, heId, inMoscos¡, U. S. S. R. )

FowJ-er, c. w. 1995. An evaluation of the role of entanglementin the poputation dynamics of northern fur seals on thePribilof rslands. rn: R. s. shonura and H. o. yoshida

(editors). proceedings of the workshop on the Fate and

rnpact of Marine DebrÍs, 26-29 Nov. 1994, Honoruru, Hawaii,p. 291-307. u.s. Dept. co¡nmer., NOAA Tech. Memo. NMFS,

NOAA-TM-NMFS -SWFC-s 4 .

Fowler, c. w. L997. Marine debris and northern fur sears: A

case study. Mar. polrut. Burl. 18(68):326-335.

15

Fowler, c. W. L988. A Review of seal and sea lion entanglement

in marine debris. In: D. L. Alverson and J. A. June

(ediÈors), Proceedings of Pacific Ri¡r Fishermenrs Conference

on Marine DebrÍs, Kai1ua-Kona, Hawaii, ocÈ. 13-16 , Lgg7,

p. 16-63. Natural Resources Consultants, 4055 2Lst Àve. w.,SeatÈle, WA 99199.

Fowrer, c. w., R. Merri.ck, N. Baba. 1999. Entangrement studies,St. PauI Island, 19gg; Juvenile maLe roundups. NWAFC

Processed Report 89-01. NaÈl. Mar. Mamnal Lab., Northwest

and Alaska Fish. Cent., Natl. Mar. Fish. Serv., NOAÀ,

Seattle, WA 98115, 24 p.

Fowrerr. c. w., R. Merrick, N. Baba. 1990. Entanglement studies,St. Paul fsland, 1989, juvenile nale roundups. fn:H. Kalinura (editor), Fur seal rnvestigaÈions I rgBT and

1988, p. 85-99. NOAA Tech. Memo. NMFS F/NWC-I8O.

Fowler, c. w., R. Merrick and J. D. Baker. (in press) studiesof the population level effects of entanglernent on northernfur seals. proceedings of the second rnternationalconference on MarÍne Debris, HonoluJ.u, Hawaii, Aprir 2-7,1989. (Available D922, user serv. Branch, Environ. sci.Inf . Cent., NOÀ.A, Roc)anil1e, MD. )

Gentry' R. L-, and J. R. Hort. Lgg2. Egr¡ipment and techniquesfor handling northern fur seals. u.s. Dep. commer., Natl.oceanic Atmos. Àdmin., Natl. Mar. Fish. serrr., NoÀå, Tech.

Rep. NMFS ssRF-759, 15 p. (Àvailable DB2z, user serr¡.Branch, Environ. sci. rnf. cent., NOAA, Rockville, MD.)

Table 1. --Surnmary of roundups ofseal males conducted onJuly of 1989.

juvenile (subadult) norÈhern furSt. Paul Island, Alaska, during

Taqqed TotalDate Totala in se-a-Isb seals(Ju1y) Location rounduÞ resighted tagcred

L414L4L4L51515151515151515161.61616161616161818181819191919192L2L2L2I2222222223232323232323

7713323569637I

13264535153195

51273494245274280LO72073L7472642742136387209318328

9413021,467].492L643483602LT11822925L605L32316227L79277

003030503008922000203

L231303061030L34004300730

Tolstoi SandsTolstoi SandsTolstoi SandsZapadni Reef SandsGorbatchReef NorthReefReefReefReefReefZapadni Reef SandsZoltoi SandsKitoviLittle ZapadniLukaninPolovínaPolovinaPolovÍnaZapadniZapadni SandsMorjoviVostochniVostochniVostochniTolstoiTolstoiVostochniVostochniZapadni Reef SandsGorbatchReefReefZoltoi SandsKitoviReefReefReefLittle ZapadniLukaninPolovinaPolovinaPolovinaZapadni.Zapadni Sands

01L430211203I45020435310133203361314032512412

L7

Table L.--Continued.

Date Totala inTaggedsealsÞ

Totalseals

224238303

3686

823380

40222776

881091482494L7L87

792L2300496

18,565

"seals that are judged to be of the size that srere taken in thecommercial halr¡est prior to 1995.bseals which had any kind of tag in eiÈher fore-fripper and that!î¡ere successfguy restrained to read the tag. rncrï-des any thatvrere resighted more than once this year.

2424242424242425252525252525252626262626

Totals

TolstoiTolstoiTolstoiZapadniZapadniZapadniZapadni Reef SandsMorjoviMorj oviMorj oviVostochniVosÈochniVostochniVostochniVostochniKitoviReefReefReefZoltoi Sands

31111400351110162713

140 L26

00300900253006000010

IB

Table 2.--List of orange broad banded Allflex tags applied. tonorthern fur seals during roundups conducted on st.Paul fsland, Alaska, 1999. Entangling debris wasremoved from entangled seals prior to being rereased.

Tag Date Entangled (e)number (Julv) sex Location contior (c).

1151TLs2r.153LL541L551156LI571158115911601161II621163116411651166LL67116811691170LL7 LIL721173LL7 4LL75LL76LL771178LL79118 01181LLg2118311841185118611871188118911901191LT92119 3LIg4

l4L414L4I4L5151515L51515151515151515151515151515151515151515151515161616161616161616L717

mmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmnff

Tolstoi SandsTolstoi SandsTolstoi SandsZapadni Reef SandsZapadni Reef SandsZoltoi SandsZoltoi SandsZoltoi SandsZoltoi SandsZoltoi SandsZoltoi SandsZoltoi SandsZoltoi SandsZoltoi SandsZapadni Reef SandsZapadni Reef SandsZapadni Reef SandsZapadni Reef SandsZapadni Reef SandsZapadni Reef SandsZapadni Reef SandsZapadni Reef SandsGorbaÈchGorbatchGorbatchReefReefReefReefReefReefReefReefKiÈoviKitoviPolovinaPolovinaLittle ZapadniLittle ZapadniZapadni SandsZapadni SandsZapadni SandsZapadni ReefZapadni Reef

êcceêeêeccc

c

ccc

cccce

ce

ccôc

ceôôeeccf"f"

l9

Table 2.--Continued.

Tag Date Entangled (e)number (July) sex Location contior rèt'11951196TT971198119912 0012 01L20212 03L20412 05I206L20712081209L2LOL2LTT2L2L2L3L2L4T2L5L2L6L2L712 18].2L9L220L22LL222L223L224L225L226L227L228L229L230L23LL2321233L234L235L236L237L238I239

1818181818181818

1818t818181818181818181818191919191919191919191920202L2L2L2L222222222222

f"f"e4¡

cc

ê

e

cccceeccecceccccèeeccef"faeccôÀ

eccôc

ffmmmmmm(not

mummmmmmmmmmmmmmmmmmmmmmff,mmmmmmmmmm

Zapadni ReefZapadni ReefMorjoviMorj oviMorjoviMorj oviMorj oviMorjovi

used)Morj oviMorjoviMorj oviMorjoviMorjoviMorj oviVostochniVosÈochniVostochniVostochniVostochni SandsVostochni SandsVostochni sandsVostochniVostochniVostochniVostochniVostochniVostochniTolstoiTolstoiTolstoiTolstoiZapadni Reef SandsZapadni ReefZapadni ReefZoltoi SandsReefReefReefReefReefReefReefKitoviKitovi

20


Tag Date Entangled

1240L24L1242]-243L2441245L246].247L248124912501251L2521253L2541255L2561-257L258L259L260L26LL2621-263L264t265].266L2671268L269L27 0L27LL272L273L274L275L276L277t278L279128012 81L282L2g3L284

222323232323232323232323232323232323242424242424242424242424252525252525252525252525252525

mmmmmmmmmmmmmmmmlllmmmmmmmmmmmnmmmnmmmmmmmmmmmm

KiÈoviLukaninLukaninLukaninPolovinaPolovinaPolovinaPolovinaPolovinaPolovinaPoLovinaLittle ZapadniLittle ZapadniLittle ZapadniLittle ZapadniZapadniZapadniZapadniTolstoiTolstoiTolstoiZapadniZapadniZapadniZapadniZapadniZapadniZapadniZapadniZapadniMorjoviMorj oviMorjoviMorj oviMorj oviMorjoviMorj oviMorjoviVostochniVostochniVostochniVostochniVostochniVostochniVostochni

ce

êcc

cc

cceccecceccecc

ecebcccÂ

cA

cceccc

2I

Table 2.--Contínued.

Tag

L285L286L287

252526

ceà

mmm

VostochniVostochniReef

tFemale seal tagged for Japanese behavioral study with rad,iotransrnitters.bThis seal hadcontrols were

been tagged as a control on Kitovi in 1986; notagged for this seal.

Table 3.--List of tagged northernactivities on St. paulunless noted otherwise.

fur seals seen during JuIy juvenile male roundupfsland, l-988. Tags were seen on both fore-flippers

Debris was removed from entangled seals.Date Tag Taq Tag Entanqlement

es

14 Tolstoi Sands

L4 Tolstoi Sands14 Zapadni Reef Sands

14 Zapadni Reef Sands 14 Àllflex

5184 ÀIIflexAO343O monelO478 ÀIIflex

white

orange

blue

pc

Tagged on Aug. 3, 1986 atToIstoi.Tagged in L987 as a pup.Tagged on Aug. 24, 1-986 atZapadni.Tagged on JuIy 17, 1988 at Reefwith the same debris. At thattine was also fit with radio.Ànimal was in very poor conditionon the 7/L4 sighting.Tagged on July 20, 1988 atVostochni.Tagged on JuIy 29, 1988 atVostochni.Tagged July L7, 1988 at Reef.Tagged Àug. 25, 1986 at ZoltoiSands. Both tags present, Ieftone was read.Showed a rub mark on its neck.Tagged on Oct. 16, 1986, on Reef.Tagged on July I?, 1988 at Reef.Tagged on July 31, 1988 atKitovi.Tagged on July I7, L988Tagged on JuIy 31, 1988Tolstoi.Tagged in L987 as a pup.Tagged on Oct. 2 , 1986 ,Zapadni.

at Reef.at

at Little

L4 Zapadni Reef Sands 54 ÀllflexL4 Zapadni Reef Sands 1-23 ÀItflex

blue

blue

blueorange

orangewhiteblueblue

blueblue

orange

15 Gorbatch1-5 Gorbatch

1.5 Gorbatch15 Reefl-5 Reef15 Reef

24 ÀIlflexO774 ÀIIflex

1157 Àllflex5l-17 ÀIIf lexl-8 ÀIlf lex161 Àllflex22 ÀIlflex148 ÀIlflexAOO432 monel0852 ÀIlflex

cc

etcec

cc

l_515

1515

ReefReef

ReefZapadni Reef Sands


Entanglg¡nent

15 Zapadni Reef Sands


t5 Zoltoi Sands

15 Zoltoi Sands

15 Zoltoi Sands

15 Zoltoi Sands15 Zoltoi Sands15 Zoltoi Sands15 Zoltoi Sands

Zoltoi SandsKitoviKitoviKitoviKitovi

16 Little Zapadni

5178

L23

o383

À04869

55

153o17303300604

ÀIIflex

Àllflex

Àllflex

monel

Àllflex

ÀIlfIexÀlIfIexAIIflexAIIfIex

white

blue

ornage

blue

blueoran9eorangeorange

c

gt

cccc

Tagged on Àug. 3, l_996, âtTolstoi.Tagged on July 29, t_988 atVostochni. Second sighting int_989.Tagged July 23, 1986 on Gorbatch.Tag not sighted on left.Tag hole in teft. Tagged in LggTas a pup.Tagged JuIy 2O, l_988 onVostochni.Tagged JuIy 31, l_988 on Tolstoi.Tagged Àug. 7, 19BS en Gorbatch.Tagged JuIy 19, 1986 on Reef.Tag on right tras present but notread; should have been 0605. lrlastagged on Zapadni, in August of1986.Tagged in I9B7 as a pup.Debris removedTag nissing on right side but thepost of a tag was seen.OnIy one tag read, side notnoted.Tag missing on right side, taghole seen. Tagged in 1-}BT as apup.Tagged July 21, l_9g8 on LittleZapandi.

NUJ

t_51616

16

À0535888809

LL7 4

À01199

60

monelÀllflexRoto

ÀIIflex

monel

Àllflex

blueblue

oran9e

blue

en

16


L6 Little Zapadni

16 Little Zapadni

16 Littte Zapadni16 Little Zapadni16 LukaninL6 Polovina

16 Polovina

16 Polovina

16 Polovina

16 Polovina

16 Polovina16 ZapadniL6 Zapadni16 Zapadni

16 Zapadni Sands16 Zapadni Sands16 Zapadni Sands16 Zapadni Sands

L23

0419

1169LL72143oo71

0105

o494

0732

0954

40234911551t-685I44

1L65LL71-À03430bc2249

Allflex blue et Tagged on July 29, l_98g atVostochni. Third sighting in1989.Tagged on Little Zapadni, July27, 1996.

Tagged JuIy 30, l_988 onTagged July 20, 1985 onNo tag on left.Tagged JuIy 27, 1985 onsection 7. No note madeon right.Tagged Aug. 25, t_986 onTag hole on right.Tagged Aug. 24, l_986 onVostochni. No note made on whichside tag was observed.Tagged Oct. B, 1986 on Morjovi.Tag with number 0955 observed onright flipper.Tagged in 1-987 as a pup.

Tagged at Zapadni on Aug. 1,1986.

Tagged in I9B7 as a pup.

Allflex

ÀIlflexÀIlflexÀIlflexAIIflex

Allflex

Àllflex

ÀIl-f lex

Àllflex

monelÀIIflexÀIIfIexAllflex

ÀIlfIexÀlIfIexmonelmonel

orange

orangeorangeblueorange

orange

orange

orange

orange

orange-orangewhite

orangeorange

cccc

Zapadni.Tolstoi.

Reef,of tag

Morjovi.N)È

etcc

cc


Date Tag Taq Tacl EntanqlementES

18 Morjovi

18 Morjovi18 Morjovi18 Vostochni

LB Vostochni Sands19 Tolstoi1-9 TolstoiL9 Tolstoi

19 Tolstoi19 Tolstoi19 Tolstoi19 Tolstoi1.9 Vostochni19 VostochniL9 Zapadni Reef Sands

À01931 MonelM8346 Monel037O Àllflex66 ÀIlflex28 Àllflex29 ÀIlflex54 ÀIlflex

0422 AlIflex0423 ÀIlflex1170 ÀIIflexlL78 ÀIlflex1210 ÀIIflex5145 AlIflex879 Roto

orange c

orange etorange corange corange etwhite cblue

orange e'orange c

0489 ÀlIflex orange c Tag seen on left side but notread. Tagged on Morjovi Àugust25,1996.Tagged in L9B7 as a pup.Tag on right with number: M8345

c Tagged on July 23, 1986 onTolstoi.

Tagged JuIy 18, 19BB at Tolstoi.Tagged July 18, 19BB at Tolstoi.Tagged JuIy 20, L98B atVostochni.Tagged JuLy 27 , t_986 at ZapadniReef.Tagged JuIy 29, 1986 at Tolstoi.

Tagged Àug. L, 1986 on Zapadni.This number was on the bottonblade. Top btade was broken offand there hras no tag on the léftside.The "À'r was the Russian Crylic À.No tag in the left side.

Hole in right flipper. Tagged in1,987 as a pup.

c Tagged July 19, i.989 on Reef .c Tagged JuIy 19, 19Bg on Reef.

orange

blueblueblueblue

eccc


2L Gorbatch2L Gorbatch2L Gorbatch

2I Reef2L Reef

YIA2237 monel

1158 Allflex1175 Allflex403919 monel

3745

Allflex blueÀIIflex blue


Date Tag T3g Entanglgment.

2L Reef2L Reef

2L Reef2I Reef2L Reef2I Zoltoi2L Zoltoi

2L Zoltoi

22 Kitovi22 Reef22 Reef22 Reef

22 Reef22 Reef22 Reef22 Reef23 Little

23 Little

23 Lukanin23 Lukanin23 Lukanin23 Lukanin23 Lukanin

Sands

Sands

Sands

Zapadni

Zapadni

880796

11825140À053580354

0357

7

o094549810582

L204931168118270

875

0513À01091AO14 53À03 53 0407 3 13

ÀIIfIexÀIIfIex

ÀllflexÀIIflexmonelÀIIfIex

ÀIlfIex

Àllflex

ÀllflexRotoÀllflexÀlIfIex

ÀllflexÀllflexÀllflexÀIlfIexÀllflex

Roto

ÀIlflexmonelmonelrnonelmonel

blueorange

orançtewhite

orange

orange

blue

orangeblueblueorange

orangeblueorangeorangeblue

blue

orange

e'c Tagged Sept. 24, t9g6 on Reef.

No tag read on right.cc Tagged Àug. 1, i.986, Zapadni.

Tagged in L9B7 as a pup.c Tagged JuLy 22, 1986 on Zoltoi

Sands. Hole in left flipper.c Tagged July 22, 1986 on Zoltoi

Sands. Hole on left.Tagged July L6, t_998 on ZoltoiSands.Tagged July 24, t-995 on Morjovi.Tag on right on1y, tear on left.Tagged JuIy 25, tgBB on Tolstoi.Tagged Aug. 1986 on Reef. Tagnissing on right.Tagged July 26, 1988 on Kitovi.

Tagged JuIy 22, 19Bg on polovina;also tagged with radio tag.No note of side on which tag wasread.

c Tagged July 31, 1986 on Lukanin.Tagged in 1987 as a pup.Tagged in L9g? as a pup.Tagged in I9B7 as a pup.Tagged in L9g7 as a pup.

c

cc

etcccc

¡\)ot


Date Tag Tag Taq Entancrrementes

23 Polovina

23 Polovina23 Polovina23 Polovina

23 Polovina

OO71 Allflex orange

bE254O monel7 AIIfIex blue64 Àllflex blue

0343 Allflex orange

c Tagged July 2O, 1985 on Tolstoi.Left flipper had hole.Tag hole in left flipper.

c Tagged JuIy l-7, L988 on Zapadni.c Tagged JuIy 21, 1988 on Zapadni

complete with radio tag.c Tagged JuLy 22, 1986 on Polovina.

Tag sighted and read on leftonly, no note of right flippertscondition.

c Tagged Aug. 24, 1986 on polovina.Tag number 0765 on right.Tagged in 1987 as a pup.

N)

Tagged in Lg87 as a pup. \'r

Tagged in 1987 as a pup.

Tagged July L2, 1985 on Morjovi.No note of tag on left side.Tagged Aug. 4, 1986 on Lukanin.Tag scar on left.Tagged July 23, 1986 on Tolstoi.No tag on right.

c Tagged JuIy 22, 1988 on Polovina;also tagged with radio tag.

23 Polovina

23 Polovina

23 Zapadni23 Zapadni Sands23 Zapadni Sands24 Tolstoi

24 Tolstoi

24 Tolstoi24 Tolstoi24 Tolstoi24 Zapadni

24 Zapadni24 Zapadni24 Zapadni

0764 ÀllflexÀ04855 ¡nonel

À01429 monelÀ06155 monell{,41462 monelO034 Allflex5187 ÀllflexO37l- ÀlLflexL245 Allflexb43416 monel70 ÀllflexLL72 Àllflex1186 Àl_lf lex1,252 Àllf lex

orange

orange c

white et

orange corange c

blue

orange corange etorange c


Entangl.ement

24 Zapadni

24 Zapadni25 Morjovi

25 Morjovi25 Morjovi

25 Morjovi

25 Morjovi25 Morjovi25 Morjovi

25 Vostochni25 Vostochni25 Vostochni

VostochniKitovi

Kitovi

Kitovi

5137 ÀIIflex white

M8263 nonel350 AIlflex orange

xtf636507 42

51 55

5833À01354À07195

L2LIL2205195

bA657Àooo5t-

1_59

0518

Àllflex

Riesemonelmonel

ÀllflexAllflexÀIIflex

monel-monel

Àllflex

ÀI-If lex

orange

orange?

orangeorangewhite

blue

orange

monelAIIflex white

Disentangled but too big to takecontrols. Tagged on Zapadni Aug.L,1996.

Retagged 1-270 with broad orangeAIlfIex tags. Tagged JuIy 22,1986 on Kitovi as a control. Thefirst control to becomeentangled. No tag on left.No note of tag on left.Tagged Aug. 24, t_986 onVostochni. Tag number on rightsighted but not read.Tagged Àug. 3, t9B6 on polovina.No tag sighting on right.No note of tag on right.Tagged in 1987 as a pup.Tagged in l-98? as a pup.

e'N@

e"cc

2526

26

26

Tagged on Vostochni, Aug. 5,1986.

No tag on left. Tagged in L9B7as a pup.Tagged on July 31, 1988 atKitovi.Tagged on JuIy 3L, 1986 atKitovi.


Entangl.ement

26 Kitovi

26 Kitovi26 Kitovi26 Reef

26 Reef26 Reef26 Reef26 Reef26 Reef26 Reef

26 Reef26 Reef26 Reef26 Zoltoi Sands

Zoltoi SandsZoltoi Sands

0956

L257À00599401461

8193L32154o3820582

L2331250MKL4770354

1164L239

ÀIIfIex

Allflexmonelmonel

AlIfIexÀllflexÀllflexÀIIflexÀllflexÀIIf1ex

ÀIlfIexÀIIfIexmonelÀIlfIex

ÀllflexÀlIflex

orange

orange

blueblueorangeblueorangeorange

orangeorange

orange

orangeorange

c Tagged on Oct. B, 1986 atMorjovi. Tag nurnber O95Z onright.

cTagged in L9B7 as a pup.No note of tag on left. Taggedin 1987 as a pup.

c Tagged July 25, 19gg at Tolstoi.c Tagged JuIy 26, t98g at Kitovi.c Tagged JuIy 30, 1985 at Tolstoi.c Tagged JuIy 3L, 19BB at Tolstoi.c Tagged July 23, 1985 at Gorbatch.c Tagged Àug. 1986, ât Reef. Tag

number O5B3 on right.g|.c

No note of tag on right.c Tagged on JuIy 22, 1986 at Zoltoi

Sands.

cc

2626

c= seals that v/ere controlssighted, et= seals from which

when tagged, ê=debris had been

seals that were entangled at tine of beingremoved earlier.

Table 4.--List of juvenile male northern fursurveys conducted in JuIy of 1989,of the debris on each animal.

entangled animals duringÀIaska, showing the nature

seals tagged asSt. PauI Island,

Tagnumber

Date(JuIy)

Location(Rookery name)

Description of DebrisType Wt. Color righ!,-

(g) neÃsr (deg. ¡ size sizeFoot-note

11s111541t_5511_5611_s71158LL73LT7611811186l-187l-18 811_8 9l-190LL971_1981 202L204L2 LO12 1112L4L217L222L223L224L227L23o-L233

L4L4L4151515151515l_61616161618181818181818191_9

1-919L92t2L

L2.4t_5. I34.8

47184.534.92.3

LL255.1

40.81.52.82701.1o.10.32.9r.4L.7

67.Os

9.21.8

911325

1684.2280

0360360360

0180

0o

360ooo

360o

180360360360300

o360

90360

360360

o90

22.522.5

20.520.3

2325.737 .721. O

27.52L.32I.325 .68.7

20.526.5

2039

2L.5

2743.3

3622.O12.447.8L9 .2

6.O2.63.54.r5.83.2

4.53.13.9

3.7

0.40.9

TolstoiZapadni ReefZapadni ReefZoltoi SandsZoltoi SandsZoltoi SandsGorbatchReefReefPolovinaPolovinaLittle ZapadniLittle ZapadniZapadni SandsMorjoviMorjoviMorjoviMorj oviVostochniVostochniVostochniVostochniVostochniTolstoiTolstoiZapadni ReefZoltoi SandsReef

trawltrawltrawltrawltrawltrawlpacking bandtrawltrawltrawlpacking bandpacking bandtrawlpacking bandmonof iIa¡nentstringpacking bandpacking bandtwinetrawltwo kindstwinepacking bandtwinetrawlgill netpacking bandtrawl

grey9reygreengreygrey9reybluetwowhitegreenblueyeIIowgreyblackclearblackgreenyeIIowgreengreentwogreenyelIowgrey9reygreenbluewhite

tvtvtvttvtItvtIItttvtvtvtvtvtmvtvtvtvtvtIvt

(,o

3.4

5.1

10. o3.81.6

5.O

5

46r7

84


Tagnumber

Date(July)

Location(Rookery name)

Description of DebrisType Wt. Color Tighþ- Wound Mesh Twine Foot_(g) ness' (deg. ) size size note

L23412351238T24IL24612 551_2 58126L1264L268r27 4L27812 81I2861287

222222232323242424242525252526

ReefReefKitoviLukaninPolovinaZapadniTolstoiZapadniZapadniZapadniMorj oviVostochniVostochniVostochniReef

antenna wirepacking bandgiII netpacking bandtrawltwinetwinestringpacking bandpacking bandtrawlrubber ringtrawlpacking bandstring

blackwhiteclearyellowgreywhitegreenwhiteyeIIowwhiteorangeblackgreywhitegreen

4.32.4o.52.5L674.O3.6l_. o1.52.24207.3

t L4.51.83.0

tIvtttttttmttttvt

90o

900ooo

360000

600o

360

2832-O6.4324.52L.5

2825.423.A2L.7

3117.8

2322.223.5

29

o.5

3.63.64.4L.7

4.45.03.3

1_.9

47 '8

L'H

vt = very tight.both çtray and orange trawl material.

1230 and 1235 ürere larger than harvestabLee entanglement rate.band and a green twine. Each had resulted in

^36O degree wounds. Seal showed evidence of severely stunted growth.

;ll" entangeling material on this seal included twine in addition to the trawlwebbing.'The debris was embedded in a wound that was healing so as to embed the debris in thefIesh.lflç gillnet on l^227 was nade of twisted twine; on L238 it was monofiliment webbing.'This seal was entangled in a twine wrapped twice around the neck. The mesh size l. thelength of the doubled l_oop.

32

Table 5.--Debris found on juvenj.le rnale fur seals in r9B9compared to seven earlier years, expressed as theobserr¡ed percent of juvenile male sèals entangled bydebris category (data for 1981-1989 frorn Fowlãr et ã1.in press).

. Entanglenent l8)

Trawl netfragrments

Monofilamentnet fragments

Plastic packingbands

Chord, rope,. stringMiscellaneous

ite¡ns

Total

Sanple size

o.29

0. 00

0. 08

0. 04

0. 03

0.43

LO2

o.24

0. 01

0. 10

0. 04

0. 01

0.41

LO2

0.30 0.22

0.01 0.02

0.07 0.09

0.02 0. 05

0.03 0. 01

0.43 0.39

LL2 87

0.36 0.27

0.01 0.01

0.05 0.06

0.08 0.07

0. 01 0.01

0.51 0.42

76 70

0. L5 0.L2

0.00 0.02

o.07 0.10

0.05 0.06

0.01 0.01

0.28 0.30

53 47

33

Table 6.--comparison of numbers of tags appried. (in parentheses)and resighted (percent resighted shown.in bracketsberow the numbers resighted) by year for entangled andnonentangled nale northern fur seals, each rowcorresponding, to the tags released in the first yearfor that rovr.'

YearControls

(Nonentangled) 1985 1986 L987 L988 1989

(L72) 37[21.5]

(27e)

13t7 .6)

40[14.3]

(104)

I14.7 )

32I r.]..5 l

20lLe.2l

(86)

Year

entangled 1985 1986 ]-987 1988 1989

(8s) I2[14.1](128)

1lL.2)

6

14 .71

(52)

0

t0l4

[3.1]

5

Ie.6](43 )

lupdated from Fowler et al. (1989).

34

Table 7.--Ànnua1 percentage frequency distribution of the size ofdebris on entangled male northern fur seals that weretagged and released (data for L983 to 1988 from FowlereÈ al. in press).

Year <150 g (8) 150-so0 g (å) >500 g (?)

19831984r-985198 619881989

Total

845778

L285343

443

53 (63)46 (81)s6 (72)e2 (72)38 (72)34 (7e)

3Le (72)

1e (23)7 (r2)

16 (20)27 (2L',)8(15)7 (L6)

84 (le)

12 (L4)4(7)6(8)e (7)7 (r3)2 (s)

4o(e)

Table 8.--The_numbers and percentages of tagged northern furseals listed in Table 7 ttrat were-iesighted by year inrelation to size.of.entangting debris ãna yeai jupdatedfrom Fowler et al. in press). -

Year Yeartagged resighted

Size of debris<1s0 g(t) 150-500 g(t) >5oo g(Z)

198319831983198319841984L98419851985198 6198519861988

Combined

1984198519861988198519861988198619881988198919891989

years

18(34)4 (8)3 (6)1(0)

14 (30)e (16)0 (0)e(16)L (2)6 (7)0 (0)3 (3)4 (11)

72 (25)

3 (16)1(s)0 (o)0(0)2 (2e)0(0)0 (0)3 (1e)0 (0)0 (0)0 (0)0 (0)1(13)

10(13)

2 (L7)0 (0)0(0)0(0)0 (0)0 (0)0(0)0 (0)0(0)0(0)0 (0)1 (11)0(0)

3 (8)

35

Table 9. --compari.son of numbers of tags applied to ent,angled andcontrol juvenile male northern iur seals in 1995 , !9g6 |L988 and 1989 with the nurnbers in each categoryresighted the same season. The numbers Ín parãnthesesare.the percent of the tags applied thaÈ wereresighted.

Number of Èags

Year

Control-s

Àpptied Resighted

Entancrled

Applied Resighted1985

1986

1988

1989

TotaI

t7o 3s (20.6)

16s s4 (32.7)

104 2r(2O,21

86 20 (23.5)

525 130 (24.8)

2L(27.6)

re (27 .t)1s(28.8)

8118.6)

63 (26. 1)

76

70

52

43

24L

36

g 0.6(¡'c(l,

o

É 0.4(¡,

gEt.t

,.L= 0.2

rigure 1.

Year

The percentage of Juvenile male northern seals foundentangred in the commercial han¡est from Lg67 to 1984and in research roundups from 1995 to 19g9 on st. paulIsland, À1aska (updated from Fowler 1997).

37

Þ(¡)

B 0.6o

oo(úÈ 0.3(l'

(úõcc

f igure 2.

Number of Years after release

Relative rates of return for entangled juvenile tale,northern fur sears Is (nonenta!9rea[ããgãa seals) for I als (updated fromFowler et al.r-in I a from thislãËãifl. eacù aatì the rraction ofentangled seals rel the fraction of;;üåt; resishted ) ror the;;;;+;r,ãittg-iit" intenrar (for exampre' there a5?-twoãã¿ã-pãints ior three years corresponding to the le8s-88and tàge-gg interrrals) .

38

(DE.44E(Ean

o

oË22o-

0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0

Weight (kilograms)

rigure 3. Size frequency distribution of trawl net debris foundon entangled juvenile male northern fur seals, July1989, St. Paul Island, Alaska (size measured inkilograrns) .

On seals N=16

39

å60E(ltooËËso(¡,o-

50402010 30

Stretched mesh size (centimeters)

Figrrre 4. size frequency distribution of Èrawl net debris foundon entangled juvenile male northern fur seals, July1989, st. paur rsrand, Araska (size measured as reñgthof stretched uesh of trawl net fragments).

entanglement studies, st. paul island, 1989: juvenile male ... · this report presents the resulfs...

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