INSTITUT ZA OCEANOGRAFIJU I RIBARSTVO - SPLITSFR JUGOSLAVIJA

No. 63 BILJEŠKE- NOTES 1985.

A systematic study on Carangidae (Pisces)employing the otolith characters in the

eastern Mediterranean

Sistematski pristup izucavanju porodice Carangidae (Pisces)iz istocnog Mediterana na osnovu karakteristika oto/ita

Nilgiin A k kir a n

Institute of Marine Sciences, Middle East TechnicalUniversity, I9el, Turkey

Nine species belonging to seven different genera in the family Carangidaewere investigated from the .systematics point of view employing the otolithcharacters along the south eastern coast of Anatolia. The otolith of eachspecies was described in detail and its figure was given. The morphometriccharacters were meas ured and their 950/0 confidence limits were given if thesample size was more than three. It was observed that the otoHth charactersin the family Carangidae were species specific therefore identification of thespecies from the otolith was rather easy.

INTRODUCTION

Due to its characteristic shape and features for each species, otolith iscommonly used in the systematic studies of both fossil and recent teleostfishes. Especially in the paleontological studies it is the best remain fromthe fossil teleost, because the other remains are found more seldomly G a e-me r s (1968). Additionally the specific shape of the otolith is used in thestomach analysis of the fish predators. Fishes eaten by predators can beidentified from otoliths even after soft parts and bones have been digestedF r o s t and Lo w r y (1981).

MATERIALS AND METHODS

Fish samples were collected by the gill net and' the entangling net,however some species were also caught by the deep trawling. The capturedspecies were identified and the totallength was meas ured individually. Someauthors had reported that sagittal otoliths of the same individual can vary

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greately in size Rei n s c h (1968) and B i n g el (1972). There are no recordson such differences for the north eastern region of the Mediterranean the-refore without differentiating, either the right or the left otolith from theeach centimeter group of the fish obtained was removed, and kept in a paperenvelope. The otolith of each species were drawn using the 450 drawing prismand described employing the morphologic and the morphometric characters.The morphometric characters were given as ratios as applied by H e c h tand He c h t (1979). If the sample size is more than three, 95% confidencelimits of the morphometric characters were also given.

The abbreviations used for the morphometric characters are as follows:OB : Otolith breadth

OD : Otolith depthOL : Otolith lengthn : Sample size

TL : Total length of fish

RESULTS

Caranx crysos (MITCHILL, 1815), (Figure la)

Otolith very delicate and elongated. Rostrum prominent and sharplypointed. In the fish larger than 22.4 cm in total length separated and pointedantirostrum observed. In the smaller individuals antirostrum connected torostrum and blunt. When antirostrum present, excisura ostii present and sharp.Sulcus acusticus deep. V-shape intrusion of osti:um emending into cauda.Cauda slightly bent posteriorly to edge of otolith. Both cristae poorly deve-loped, especially at posterior part of cauda. Dorsal area narrow and extendingto edge of antirostrum on dorsal side. Entire edge highly denticulated. Lateralsurface well concave and deeply striated; Its anterior and posterior sidestwisted laterally. MediaI surface convex along entire length of otolith.

Morphometric characters:n=6

OL : TL = 1 : 42.25 :t 5.45OL : OB : OD = 1 : 0.33 :t 0.02 : 0.11 :t 0.1

Caranx dentex (SCHNEIDER, 1801), (Figure 1b)

Otolith's shape elongated parallelogram. Rostrum and antirostrum pro-minent and pointed. Sulcus ac.usticus deep. Os ti um slightly expanding onrostrum and cauda slightly bending posteriorly to otolith edge. A large slopeinclining from dorsal -to ventral in posterior part of cauda. Cristae welldefined. Dorsal area deep, and undulated on dorsal side. Its posterior andanterior ends unclosed. Edge denticulated. Lateral surface slightly concave onits ventral side and almost flat on rest. MediaI surface slightly convex.

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Morphometric characters:n=3OL:TL= 1 :52.17OL : OB : OD = 1 : 0.39 : 0.14

a

b

3mm,c

~ ~ ~d ' 3mm ,

Figure 1: a. Left sagitta of Caranx crysosb. Right sagitta of Caranx dentexc. Right sagitta of Caranx rhonchusdj Right sagitta of Lichia amia

Car,wx rhonchus (E. GEOFFROY SAINT-HILAIRE, 1817), (Figure le)

Otolith oval and rather thick, especially on ventral side. Rostrum pro-'nlinent and often pointed. If ant;"'ostrum present, exeisura ostii defined. In<:ome otoliths Clntirostrum connected to base of rostrum. In such a case a

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groove extending between them or antirostrum fused into rostrum. Sulcusacusticus deep. Ostium-cauda interface with pit like formation. Cauda stronglybent on its posterior part to ot6lith edge. Cristae well defined. Dorsal areaterminating before reaching dorsal edge of antirostrum. Edge lobed. Latera 1surface deeply striated and concave dorsally and flat ventrally. MediaI surfaceclearly convex.

Morphometric characters:n=7OL : TL = 1 : 33.99 :!::1.94

OL : OB : OD = 1 : 0.49 :!::0.01 : 0.14 :!::0.01

Lichia amia (LINNAEUS, 1758), (Figure ld)

Otolith small and elongated, and thickened on dorsal side. Rostrum andantirostrum prominent. Excisura ostii present. Sulcus acusticus rather deep.Ostium inclining slightly towards dorsal edge. Inclination extending into cauda,but a contrast slope from dorsal to ventral edge of cauda present. Caudastraight and slightly expanded. Dorsal area rather deep and narrow, andextending to base of antirostrum. Edge lobed on dorsal and poster~or sides,on other si des nearly smooth. Lateral surface inclining to edge on dorsal andposterior sides. MediaI surface gently convex.

Morphometric characters:n=1OL : TL = 1 : 86.00

OL : OB : OD = 1 : 0.35 : 0.12

Scyris alexandrina (E. GEOFFROY SAINT-HILAIRE, 1817), (Figure 2a)

Otolith oval in shaped, however its anterior part slightly expanded.Rostrum and antirostrum prominent and with broad bases. Excisura ostiishort and sharp. Sulcus acusticus deep. Ostium narrow on rostrum. Caudatermin at ing with slight curvature ne ar posterioventral edge of otolith. Cristaepoorly developed. Dorsal area narrow and shallow. Edge thinly lobed. Lateralsurface concave and highly striated. MediaI surface convex and relativelysmooth.

Morphometric characters:n=7

OL : TL = 1 : 55.42 :!::3.57

OL : OB : OD = 1 : 054 :!::0.03 : 0.16 :!::0.02

Selar djeddaba (FORSSKAL, 1775), (Figure 2b)

The unique sagitta was broken at its anterior tip when removing. Otolithslightly elongated. Rostrum and antirostrum prominent. Antirostrum pointed.Excisura octii short. Sulcus acusticus deep. Cauda strongly bent towards edge

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of otolith. Cristae poorly developed especially at the end of cauda. Cristaeinferior connected to edge with a stria. Dorsal area small and shallow, andextending to edge between rostrum and antirostrum. Edge lobed on dorsalside. Lateral surface deeply striated. Deep gro ove extending from excisuraostii to center of otolith on lateral surface. Otolith slightly concave to flatlaterally and convex medially.

a

b

c

Figure 2: a. Left sagitta of Scyris alex andrinab. Right sagitta of Selar djeddaba

c. Left sagitta of Seriola dumerili

3mm

Due to broken anterior tip of the otolith, it is impossible to give themorphometric characters.

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Seriola dumerHi (RISSO, 1810), (Figure 2c)

Otolith eIongated and thin. Rostrum prominent and pointed. Antirostrumvery small and nearly fIat. Excisura ostii very short. Sulcus acusticus deepV-shaped intrusion of ostium extending into cauda. Ostium narrow, caudaexpanded and bent posteriorly. Cristae well deveIoped. Dorsal area deep andterminating before reaching edge on antirostrum. Edge Iobed on dorsal andposterioventral sides. Lateral surface well concave and deepIy striated. Mediaisurface well convex.

MJrphometric characters:n =, 1

OL : TL = 1 : 62.25OL : OB : OD = 1 : 0.32 : 0.09

a 3mm

b

Figure 3: a. Left sagitta of Trachynotus ovatus

b. Right sagitta of Trachurus trachurus

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3mm

Trachynotus ovatus (LINNAEUS, 1758), (Figure 3a)

Otolith oval to elongated. Rostrum prominent, its anterior tip rounded.In some otoliths rostrum protruding on dors al side. Antirostrum rather longand pointed. Excisura ostii sharp. Ostium not expanding on rostrum:, butnaving V-shaped intrusion into cauda. Cristae poorly developed, e3peciallycrista superior weakly defined. Dorsal area shallow and extending to base ofantirostrum. Edge generally lobed on dorsal side and serrated to smooth onother sides. Lateral surface with groove extending from excisura 03tii tocenter of otolith. In some otoliths agroove on medial surface connected todorsal edge below do rs al area. Otolith slightly concave laterally and convexmedially.

Morphometric characters:n=7

OL : TL = 1 : 48.39 :I: 2.38

OL : OB : OD = 1 : 0.42 :I: 0.01 : 0.17 :I: 0.01

Trachurus trachurus (LINNAEUS, 1758), (Figure 3b)

Otolith oval. With increasing length of fish some differences observedon appearance of otolith. In some fishes (TL > 11 cm) otolith pointed poste-riorly. Antirostrum folded back towards medial surface and excisura ostiisharp. In smaller individuals posterior tip rounded, antirostrum and excisuraostii absent. Sulcus acusticus deep. Ostium having V-shaped intrusion intocauda. Posterior part of cauda slightly bent towards edge of otolith. Cristaewell developed. Dorsal area extending to antirostrum and connected to edgeon dorsal side. Otolith concave laterally and convex medially. Edge roughlylobed (TL > 11 cm) or thinly and highly lobed (TL < 11 cm).

Morphometric characters:n = 12OL : TL = 1 : 32.59 :I: 2.48OL : OB : OD = 1 : 0.54 :I: 0.03 : 0.17 :I: 0.01

DISCUSSION

The similar study in the Eastern Mediterranean was done on the familySparidae A k kir a n (unpubl. data). In this fish family the general appea-rances of the otoliths are similar to each others in a varying degree thereforeidentification of the species employing their otoliths are with some difficulties,yet possible. In the family Carangidae the otoliths have specific shapes andfeatures, so the investigated species are easyly identified from the otolithcharacters.

In Carangidae, the differences in the otolith characters in the same genusare even very noticeable. In the genus Caranx, the most noticeable difference

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between the otoliths is observed in the general shape; It is elongated inCaranx cryses, parallelogram in Caranx dentex and oval in Caranx rhonchus.The shape and the structure of the sulcus acusticus are important charactersin the distinguishing of the otoliths; In Caranx crysos the ostium has theV-shape intrusion into the cauda, in Carnax dentex the anterior section ofthe sulcus acusticus is slightly expanded and the cauda has the cave likeformation on its ventral side. In Caranx rhonchus the ostium-cauda interfacehas the pit like formation. It is also neccessary to consider the shape of thedorsal area; In Caranx crysos it extends to the ba8e of the antirostrum. InCaranx dentex it is undulated and both its anterior and posterior parts areunclosed. In Caranx rhonchus the dorsal area is rather broad and it terminatesbefore reaching the edge neal' the antirostrum.

The otoliths af Caranx rhonchus and Trachurus trachurus are the mastsimilar anes in the general shape, although these belang to different genera.As stated by J u I' k sc h a t (1977) for the freshwater fishes af the NorthernGermany, the ataliths af the yaung individual expase .mare ar less uncertaincharacters and as the fishes graw up some of the structures undergo varia-tians. Trachurus trachurus e:Jq)asse mast variatians with the increasingthe tatal length af the fish between the examined species. In spite af thevariations, the general shape af the otalith resembles that af Caranx rhonchus.In bath species the atalith is oval in shape, but there are certain differencesbetween them. In Caranx rhonchus the dorsal area terminates befare reachingthe edge an the antirastrum. In Trachurus trachurus it extends ta the anti-rastrum and is cannected ta the edge an the darsal side of the otolith. Thesulcus acusticus expases different characters in the bath species; The paste-rior sectian of the cauda is slightly bent towards the pasterioventral side afthe atalith and the astium has the V -shape intrusion into the cauda inTrachurus trachurus. In Caranx rhonchus the curvature af the cauda isstranger than that af the preceding species. The astium is like a pit an theastium-cauda interface. In the ataliths of the large individuals af Trachurustrachurus the antirastrum is falded back tawards the medial surface. Thischaracter is nat observed in the atalith af Caranx rhonchus. The marphometriccharacters are alsa different in the twa species. These characters were givenby Seh m i d t h (1968) as fallaws: far Caranx rhonchus from Gulf of Guinea:

aL: TL = 1 : 37.00

O~ : OB : OD = 1 : 0.51 : 0.15for Trachurus trachurus from North sea:aL : TL = 1 : 30.00

aL : OB : OD = 1 : 0.45 : 0.15

CONCLUSION

The otolith characters of the nine species belonging to seven genera inthe family Carangidae were emplayed in the systematics paint of view. Thedetailed descriptians and the figures of the otaliths were given. These aresupplemented with the morphometric characters of the otaliths. Ta providethe reliability of the morphametric characters the large number of the atoliths

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should be used. In this research it was attempted to collect the otoliths fromthe each centimeter group of the fishes, however for some species only oneotolith was obtained.

In summary, it is possible to identify the species of the family Carangidaefrom the otolith characters easily.

Acknowledgements: I would like to express my deep gratitude to Dr. FeritBingel, Middle East Technical University, Institute of Marine Sciences, forsupervising the research and for his valuable suggestions throughout the work

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REFERENCES

A k kir a n, N. In press. A Systematic Study on Sparidae (Pisces) employing oto1ithcharacters in the Eastern Mediterranean. METU Journal of Pure and AppliedSciences, 17.

B i n g e 1, F. 1972. Zur interpretation von Oto1ithenstrukturen des Dorsches (Gadusmorhua). Dipl. Arb. Univ. Kiel, 42 p.

F r o s t, K. J. and L. F. Lo w r y. 1981. Trophie Importance of So me Marine Gadidsin Northern Alaska and Their Body-Oto1ith Size Relationships. Fishery Bull.,79 : 187-192.

Ga eme r s, P. A. M. 1968. Wat Zijn Otolieten. Overdruk uit: Medede1ingen Van DeWerkgroep Voor Tertiare En Kwartaire Geologie, 5 (4) : pag. var.

He e h t, T. and A. H e e h t. 1979. A descriptive Systematic Study of the Otoli,thsof the Neopterygean marine fishes of South Africa. Part 111: E!opiformesGonorhynchiformes, Clupeiformes, and Salmoniformes. Trans. roy. Soe. S. Afr.,Part 1 : 73-95.

Ju r k seh a t, C. 1977. Eine Taxonomische Untersuchung der Schuppen und Oto-1ithen limniseher Knochenfisehe. Dipl. Arb. Univ. Kiel, Germany, 123p.

Rei n seh. H. H. 1968. Untersehiede in den Jahresringen zwischen rechten undlinken Otolithen einiger K6hler Pollachinus virens L. Ber. d. dtsch Komm f.Meersforsch., 19 : 291-294.

Seh i m i d t, W. 1968. Vergleichend morphlogische Studie tiber die Otolithen marinerKnochenfisehe. Areh. Fischereiwiss., Berlin, 19, Beiheft 1 : 1-96.

Re~eived: February 14, 1985

SISTEMATSKI PRISTUP IZUCA VANJU PORODICE CARANGluAE IZISTOCNOG MEDITERANA NA OSNOVU KARAKTERISTIKA OTOLITA

Nilgiin A k kir a n

Institut za istraživanje mora Sveucilište za tehnicke znanosti Srednjeg istoka,Icel, Turska

KRATKI SADRŽAJ

Devet vrsta sedam razlicitih rodova porodice Carangidae iz južnoistocnogobalnog podrucja AnatoHje, izucavane su sa stajališta sistematike na osnovukarakteristika otolita. Otoliti svake pojedine vrste detaljno su opasni i pri-kazani na slikama. Mjerene su morfometrijske karakteristike za koje su odre-dene granice pouzdanosti od 95°/11ukoliko je riba potjecala !iz uzorka s naj~manje tri primjerka. Determinacija pojedinih vrsta bila je u mnogome olak-šana cinjenicom da svaka vrsta pokazuje odredene specificnosti otolita.

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BILJESKE-NOTES, izdaje Institut za oceanografiju i ribarstvo Split; izlazi povre-meno. Odgovorni urednik: Dr Mira Zore-Armanda. Naklada 600 primjeraka. Tisak:

»Slobodna Dalmacija«, Split