They are purely marine in habitat .Among the cephalepods several species of squids, cuttlefishes, optopus are commercially important

Narasimham, K A

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• i . • • REFERENCE 0 Nly SUI-IMER INSTITUTE IN \ CULTTIRE OF rnIBLE MOLLUSCS HELD AT TurrCCRIN RESEARCH CENTRE OF CENTP.AL l-I.ARINE FISHERIES RESEARCH INsrITUTE trom 26 May to 24 June 1980 ,. , . ~ Centr a l ~!arinc Fis her ies Research Institut e P .B . 1912, COGHill - 682018 , I NDIA " Indian Council of Agri cult1Z'al Resoarch September' , 1980 \.If \ .. 1 FI:::,illlY MiD BIOLOGY OF' CFl'HAUPOJ:6 , '. K .A. NARASIMHAM The cepmlCJllods are distr~buted in all the' oceans of the wO[' Id fr om sha1101; inshore ar cai-t ~ deep oceanic wat ers • They ore 'purely norine in habi t at . Among the cephalepods several species of squids, cuttlefishes ~ optopi are commercially important. Until recent times there was h.."U'dly any market fO[' cephalopods in OIr country. Also the cuttlefishes are the first to be thrown out into the sea fr om the trawlers, immediately on hauling the net since the ink ejected by them contaminates the catch, p31'ticularly prawns (SiJD.s et al ., 1974) . At present with the increasing demand, the export market for cephalepods has develeped fast and they fetch a high price . A largo n1.lllber ef cephalopod species were r ecorded fr om O\r courrl;ry (Sila.s, 1968 ; Oommen, 1977). The important commercial species like Sepia aeuloota Ferussac and d' crbingny, 2' pharaonis Em'enberg, Sepiella inermis (FerUisac and d' crbigny) and Loligo duvau::eli d' crbigny which contribute to the fismry at several centres along the east and west coasts are widel¥ distribl.t ed in the Indo-Pacific r egion . EXPLOITATION AND FISHERY • The contribution of cephalopods to the norine fish catch in India varied fr om 1184 tonnes in 1970 to 15931 t onnes in 1978 (Table 1). They accO\mt ed f or 0 .1 to 1 .14% of the tetal fish pro-duction. It may be soen from the t able that since 1974 there has been a norkod increase in the catches, due to the increased number of traw-lers and also due to the insatiable demanl for cephalopods in the foreign =kets. Except for the Palk Bay squid Sepieteuthis aretipinnis Gould there is no regular fishery f or other cephalopods which arc caught incidentally in small qumtitios along with fishes in gears like trawl net, shore seine, b oat scine, gill net 1llld cast net . In the Vizhinjam • - 79 .• area hook and lines :md ~coop nets arc [llso used. The shoaling behaviour and the migration to shallw waters f or spawning by cepba-.. l opods in taken [ldvantage in condu::ting r egular fishing, as in the Palk Bay. Here the squid, 2' orctipinnis migr ate into inshore waters , by. about Februnry :md spawn till ab out June . During this period a shor e s eine called ol a ~ is used for squid fishing (Rao, 1954) . The net consists of :l r cct:mgular bag of 'about 8m x 2m withclose and wide meshed webbing . The wing ropes measure about 274 m, boor }-4 close set r ows of palm 1 01'.f ne.'U' the wings rmd 1 01' 2 rows fer the r est of the wing r ope length . In the Palk Bay rogion special squid jiggs were used previousl y (Hornell, 1917) btt now obs olete . In this method a fisherman keeps wat..cfu by sitting on a Y- sh.'1ppc-d pole called machan. A l ong jigg of 5-6 hooks is arra nged like a ' gr :tpncl which is hidden under :l he-'lp of l eaves near the mchan to lure the squids. When they appro:lCh t he l ooves . fer sp<1.wning they are lifted with a jerk . Now a modified jigging methoJ is followud in this ar ea (Snrvesa n, 1974). The jigg consists of 35- 40 e m l ong slender wire equippe-d with }-4 strong hooks on one end a nd the other i s tied to a pole which serves • as the harrlle . Tho fishormen in canoes or catam..'1raIls hook th E;> squids with t he jigg ;tith a quick jork. Also in t he Pnlk Bay area the oct opi, used ns baits , ru-e caught in shell traps (Sorvesan, 1974) . About 100 to 120 glstr opod shells like L::unbis l omb is , !2!l!!i! doli un, Ranhna bulbosa , Mur ex birgineus am HemifUles ar c strung along a thin coir rope . These lines are hid,ein 4- 6 m depth with wooden floats attached. The tr 'lps are r a ised daily and the small octopi like Octopus dollfusi and Q. globosua which take r efuge in the shell cavi-ties are disl odggd with a needle to be used a s bait, Jigging i s the most ;fidely practised method, p<'ll'ticulcrly by the Japanese in catching cephal opods . 1 llltiple mechanical jiggs ar e now used by the Japanese . In California , lampora net e ore used ." in squid fishing . The squid shoals, n.ttracte-d by light during ni.;ht t ime arc encircled nnd h.'luled into the boot by power lifted dip nets. While published informat~on is lncking on the species ;fise cephalopod landings , it appears that the cuttlefishes are domiIiant , I ---• - eo -fallowed by squids and the contribution by octopi is negligible . Future outlook : The exploratory surveys along the west coast r evealed the occU'rence of ccinmercially important species of squids such a s Symplect oteuthis am.laniensis and Loligo sPP.tSilas, 19(9),. Ther e is need t o try special fishing methods su::h. as light fishing with jiggs t o. exploi t the sqcid resoUrces (Silr:lS ot al ., 1974 ) . Present status of ut ility: Apart from their utility as foed for m9.n cephalopods are important fcrage organisms for fish, birds and ma.mmal.s in the S OIl. . At present as food they aro not a popular item in our country . However in r ecent years significa nt progress las ~o in the oxport of cephalopods to foreign countries. In 1978 frozm squids weighing 2.428 tonnes (value Rs .. 3.28 crores ) and frozen cuttle fish weighing 979 tonnes (value Rs . 1 .66 crcres) were sent t o' a nunber of c~ries , France being tho main impcrtEr . In 1977 cuttle bones weighing 49 t onnes (value Rs . 2 .99 lakhs) were exported. The cuttle-bones nre a s ource of calcium. They ore used in the IX'eparat ,ion of alrasivos a nd dentrifi()es. Also wooden or metal surfaces are poli-shed with cuttlebones . BIOLOOY Food and feeding habits: The cephalopods are carnivorous am they hunt their prey by sight . Their well develop ed eyes help th em t o pursue the prey. The flexi.ble muscular arms and t ent l;lcles with their s uckers give: , them D. strong grip over tho pr ey. Thc powerful j aws pre~ent in the buccal ross help t o cut the prey into pieces. Fishes , crustaceans and cephalopods nre the important food itans consunod by them . • P.a.o (1954)' st at ed tmt spawnErS of Pa lk Bay squid in general do not feed dU';i,ng t he -spawni ng period . High f eeding intensity in 1. ~uyp.uc eli \;:LC .~ (Oommen, 1977) dur ing Fcbruary- l1ly and the squids ' obtained during night t imo had f ew empt y stomachs (Oommen, 1976). The stuiies by Kore a nd J oshi (1975 ) also indicated that th'S • ... 81 -squid is carnivorous, cannibalistic and shows seasonal variation in, the intensity of feeding! In~. inermis high feeding intensity was observed in April- May and- no such periodicity was foun:! in ~. aculeata (Oommen, 1977) . The s quids are known to change their food with gI'owth . Vovk (cited by Arnold and Arnold, 1977) reported that in Lolil:!? pealei planktonic feeding was dominant in the snhllest size squid (75 mm mantle l ength) ,- Euphausid feeding became important t o larger squid (125 mm length ) . Cannibalism and fish feeding docn:inai;ed in- sizes larger than 160 mm . Kore and Joshi (1975) also reported in 1. duvaueeli an increase in cannibalism and decreas e in crustacean feeding fer lar ger sguid, C4-owth: Rao ( 1954) concluded that ~. arctipi nnis attains an average nantle l ength of 95, 166 and 219 .5 mm at the end of 1, 2 am 3r'd yee:r of life r espectively . Males grO\J to a larger size than females. For other species published chta are l acking . Maturity: In~. arctipinnis males att ain sSKUal maturity between 67 .5 to -112 .5 mm l ongth 'Ihen-thoy ar" O 6-14 months old; females matu-e at 102.5 to 11 2 .5 mm whan they ar e 13-1 4 months old. No published information is availablo on other species. Fecundity: Summers ( 1971) ostimated that ID1lture females of -Loligo pealei l a y between 3500 t o 6000 eggs dapewng on their size . Octopus vulgnus is perhaps most prolific, l a ying 1,50,000 eggs aver a period of f ew days . At th e other end 2. bimaculoidos lays a few hundred eggs (AkimusloJcin as eited by Holls and Walls, 1977). For Indian spccies there seem to bo no publishGd data available. S-.:awning: In §.. arctipinnis spawning commencos in January am is COrrtinuoo. till tho end of Juno (Rao, 1954) . Squids migrate into shallow inshore waters and adjacent l agoons from tr.e offshore' \Jaters by about , . Februar y and deposit t heir eggs capsules till about June. Squids arrl cuttle fishes are known to exhibit elaborate courtship befer e nating. . ~ -I - e~ . .. • on ' The eggs are depositod singly er in clusters on sticks, rods erLfloating object,s. Females show a temency to lay on existing clusters. A COlllnon site may be used by many f emales for e~ l aying fer extemed period.s a m large mass es flI'e built up . In I!lD.jerity of cephalopods . . about which informat,ion is avo.ilable, mating behaviour and/or egg l aying is !bllowed by death (Arnold a nd Arnold, 1977). cetopods to not swarm to breed (vlells a nd Wells, 1977). Fertilisation and deveJopm@!nt:' In c eFhalopods thc Bpermatophores are transf err ed along ~oove in the hectocotylus from males to the mantle cavity of females a m fertili sation is internal. The pattern of development is gooet'ally uniform in cephalopods if alloaran::o is made for the variabloamount of· yolk (Arnold and Arnold, 1977) . Alagarswami ( 1966) stu:liod the anbryonic developnent of the squid r el'err ed t o §. . arctipinnis on carroborative evidence, The early cleavage is of mer obl astic t ypo r esulting in 64 celled stage. By further margiml divisions of the blastcmeres tho blastoderm s epara-ting. t he anbryonic and non anbryonic r egions . (h the 5th day the or gan forming ar-ca.s are -noticed a nd differentiation of various ergans is ~ogress . en the ;th day the embr yo is far adwnced in deve-l opment and more or gans like tho formation of lcnse in the e;yce 'are devel oped . By tl,c 11,th day the developing embryo appears a s a miniaturc '1dult but still ~ri.t h yolk sac attached. The montle, fins, arms , ayes and t~ visc er n. l or gans are all well devoloped and the embryos move insido the chorion . en the 15th day the young hatch out and thcy r oson:ble v ery much the adult. Thay begin an indepement life . cetopods broOd their eggs (Wells and Wells, 1977). Parental care in Q. dollfusi "I'1S described by Sarvesa n (1974) . Larval histcrv: PropErly speaking there are no l arval forms in Deca-podil . Development is dir~ect to a miniat1re adult whiCh mayor may not enter into n planktonic type of existence before forming typical scho~ls or sedentary life styles (Arnold and Arnold, 1977) . In the • - 83 -Octopoda also, Wells and Wells (1977) advocate that the term ' larva ' be better avoided . Table 1: Cephalopod and total fish (i:!tohoQ . (SoIlI'ee-i .C .14 Il' .H.r ~ Annu.'ll r oports ) ---------.-----------------~-----------------------.-----Year Total Fish Catch tonnes C~halopods/ % of Cephalopods tonnes ---------------------------------------1970 10, 85 , 607 1,184 0.12 1971 11 , 61 , 389 1, 505 0.13 1972 9, 80, 049 1,026 0,10 1973 12, 20, 240 1, 394 0 .11 1974 12, 17, 797 3, 677 0.30 1975 14, 22, 693 7, 889 0.55 • 1976 13,52, 855 10, 826 0.80 1977 12, 59, 782 10, 005 0.79 1978 1 Ie, 03,607 15, 931 1 .14 -----------------------------------------------------------------------• .. 

Fishery and biology of cephalopods

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Fishery and biology of cephalopods

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