Overview of Present Status of Future Direction for Demersal Finfish Fisheires

8/2/2019 Overview of Present Status of Future Direction for Demersal Finfish Fisheires

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Indian Journal of Fisheries 29 {\,2): 104-110, March,June 1992

An overview on the present status and future prospects ofdemersal finfish resources in IndiaP BENSAM

Central Marine Fisheries Research Institute, Cochin, Kerala 682 014ABSTRACT

Wilh the introduction of mechanized bottom trawling from the late fifties, the exploitation of demersalfrnfishes atuined a 2.7- fold increase during late eighties (0.52 million tonnes). But the proportion ofproduction went dow n from about 32% of the total in 1981 to about 22% in late eighties. The resourceswhich were exploited to the optimum in the 0-50 m dq>th zone during 1985-89 were sdaenids, silverbellies, elasmobranchs, pink perch, lizard fishes , goat fishes, threadflns, eels, et c. As a result of intensivecoastal trawling and introduction of gears such as purse sein es, resources like catfishes, the whitefish, dara,karkara, koth, ghol,warn andflaiheadsdeclined in production. This was chiefly due to recruitment over -fishing resulting from the destmction of juveniles as well as the trampling of the bottom habitat. As perrecent estimate, only a marginal increase in production of demersal finfishes from the presently exploitedzoie was possible, whereas from the deeper waters about 300 000 tonnes consisting of elasmobranchs,major perches, pink perch, catfishes, lizard fishes, etc appeared po ssible. For the efficient exploitation andutilization o f these resources to be harvested, it is essential to develop adequate infrastructure facilities, postharvest techno logy, value-added products, domestic m arketing and exporL Since the large-scale bottomtrawling has been leading to deleterious effect on certain vulnerable finfish resources, there is inuninentneed for imposing certain controls on fishing in the inshore waters.

When compared with pelagic resources,proper exploitation of the demersal finfishesin India has been a recent development. Priorto introduction of mechanized bottom trawling in the late fifties, the average annualdemersal finfish production was only about0.08 million tonnes. During the third Five-Year Plan period (1961-65) there was an increased effort for mechanized commercialtrawling, marking a turning point in thedevelopment of demersalfishing.Ever since,the proportion of production by mechanizedvessels has increased from 19% of the total in1969 to about 81% in 1989. The demersalfinfish component also has increased steadilyfrom about0.19 million tonnes in 1961 toO.25million tonnes in 1970,0.42 million tonnes in1977, 0.45 million tonnes in 1982 and 0.52

Present address: Principal Scienti st.

million tonnes during 1985-89, thus registering about 2.7 fold increase over about threedecades.However, as a result of these develop-mentsi certain problems and constraints havesurfaced, both in the sphere of exploitationand of management and conservation of theresources. This paper draws attention to theneed of certain control in fish ing .Briefhistory of exploitationThe demersal habitat is abundant in finfish es almost throughout the continentalshelf, with particular dom inance in the shallow waters up to about 50 m depth. The important groups are: rays, sharks , skates, flatflshes,Jew fishes, perches, catfishes, silverbellies,lizard fishes, flatheads, etc. They inhabitsandy, muddy, rocky and coral areas, fromintertidal to deep abyss, throughout thegeographical regions and in all seasons. Hie

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March, June 1992] OVnRVIliW ON DEMIiKSAL FINH SII RESOURCES

traditional crafts and gears were designed tosuit the local sea conditions and hence variedin structure and size; non-rigid crafts along theeast coast and rigid ones along the west. Thetraditional gears are; shore seines, bottom - setgill nets, drift nets,fixedslake nets, cast nets,traps, hand lines, long lines, etc. During 1947-48 the annual demersal finfish productionamounted to about 0.08 million tonnes andduring the fifties it ranged between 0.15 and0.18 million tonnes, forming an average ofabout 24%, all by traditional crafts and gear.The progress in mechanization resulted inmore than 8 000 vessels in the mid seventies,19 000 in early eighties and 23 000 in lateeighties, most of them of about 7.5 - 14 mOAL and using bottom b-awls, gill nets, dolnets, etc within about 50 m depth. Also, therewas a notable increase in the number of indigenous crafts: from about 90 000 in earlysixties to 106 500 in early seventies, 141 000in early eighties and 170 000 in late eighties,especially plank-built boats and catamarans.Purse seines were introduced ona commercialscale in 1977,first n Kamataka and Goa andlater in Kerala. Motorization of traditionalcrafts commenced during the seventies, withplank-built boats in Maharashtra, Gujarat andTamil Nadu, followed by dug-out canoes andcatamarans fixed with outboard motors inKerala in the eighties; and numbering about15 300 in late eighties. The eighties have alsowitnessed the inb'oduction of beach-landingcrafts made offibreglassby the Bay of Bengalprogramme of the F A O, for operating in thesurf-beaten coasts of Tamil Nadu and AndhraPradesh.Present statusAs a result of the above developments,the demersalfinfishproduction increased significantly, from 0.26 m illion tonnes in 1970 to0.42 million tonnes in 1977, and their proportion varied between 21 and 35% of the total in

the seventies. But. inspiteof the increase in thetotal fish production during the eighties,reaching a peak of 2.2 million tonnes in 1989,the demersal proportion declined to 28%during late eighties. Besides, although therewas a steady increase in mechanized vessel'sproduction from 19% in 1969 to 81% in 1989,there was no marked increase in demersalfinfish production. This was chicfiy due to theconcentration of the effort to the much morelucrative shrimps for the export markets.However, there was an initial increase in catfish yield but this was followed by a decline.There was also an emergence of new fisheriesfor the pink perch from early eighties and forthe goat fishes from early nineties. Theseoperations have also resulted in the decline ofresources such as the whale shark, the dara,karkara, koth, ghol, warn, whitefish, etc.The demersal finfishes are being exploited from within about 50-70 m depth. Butduring favourable conditions, the mediumsized trawlers venture to 120 or even up to 150m depth, specially for target groups with export markets, such as cephaiopods. And, thepresent status of exploitation within the exploited zone of up to about 70 m depth may beconsidered as follows:-

Resources under optimum exploitationsciAENTDS: The Jewfishes occured up toabout 90 m depth, formed the largest singlegroup (about 20% production) and were vulnerable to trawl nets, gill nets and many ar-tisanal gears. About 14 species Contribute tothe bulk with an average annual yield of102 900 tonnes, mostly from Gujarat,Maharashua, Tamil Nadu, Andhra Pradeshand Kerala (G.O.I.1991). The productiontrend indicate that the yield from the 0-50 mdepth areas has become more or less stabilized. The stock assessment exercises haveshown that in the inshore waters of northwestcoast some reduction in effort is needed for

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BENSAM [V d. 39 , No. 1,2

Ololithes cuvieri, Johnieops macrorh ynusand J. vogleri whereas in Kerala and TamilNadu, the effort can be increased for J. sina.A marginal increase of about 18 000 tonnesfrom the presently exploited region appearspossible.SILVERBELUES: During 19 79 -8 3, the es

timated average annual landings of silverbcl-lics were 69 000 tonnes. Exploited by trawlnets and anisanal gears, this group formedabout 12% of demersal finfisfi produ ction.Maximum yield was from Tamil Nadu (about71%) followed by Andhra Pradesh (9%).Kerala (8%) and Karnataka (6%), Among 20species, Leiognathus bindus and Secutor in-sidiaior were the most dominant in AndhraPradesh and northern Tamil Nadu , cohtribut-ing to 64% and 55% respectively of the landings. The recent stock assessment studies onthese species have shown that in AndhraPradesh and northern Tamil Nadu the currenteffort may be m aintained for optimumyield whereas in southern Tamil Nadu there isscope for a marginal increase.ELASMOBRANCiiS: Tlie s ha rks, rays a ndskates, accounting for about 54 O^X) tonnes(10.5%) of demersal finfishes, were mostlycaught m Tamil Nadu, Gujarat and Maharashtra and exploited by trawls (80%) and driftnets (19% ). Sharks accounted for about 60% ,rays 35% and skates 5% with the first categorymore dominant in tlie west coast but thesecond one more in the east. The importantspecies were Carcharinus sorah, C. Uniiyatus,Rhizoprionodo n a cutus, Sphyrna blochii,Rhynchob aius sp, Dasyatus sp, Aetobatus sp,Rhinoptera sp., etc. The fishing pressure appears to have reached the optimum, althougha m.irginal increase is possible.

PINK PERCH: A lso call ed threadfinbreams {Nemipterus spp.), these were abundant in the shelf and slope w aters up to 200 mdepth and were exploited mostly by trawl nets.The annual production increased from anaverage of 22 250 tonnes during 1980-83 to

48 100 tonnes during 1984-88 and to a peakof 82 100 tonnes in 1990. Kerala contributedto the maximum (52%), followed byMaharashtra (14%), Tamil Nadu and Pon -dicherry (11%), etc. N. japonicus was mostabundant in Tamil Nadu, Karnataka,Mah arashtra and Gu jarat and N. mesoprionin Andhra Pradesh and Kerala, especiallyfrom deeper areas. Stock assessment studiesshow that from the presently exploited 0-50m depth zone there is no further scope forincreasing the production.

MAJOR PERCHES: B el o n g in g to t hefamilies Serranidae, Lutjanidae and Lethri-nidae, this group was abundant in the rockygrounds off Kerala and 7'amil Nadu and wasexploited by d.ift nets, hooks and lines andtraps. The annual average production during1985-89 was about 30 000 tonnes (5.7%)composed of Epinephelus diacanthus, E.tauvina, Pristipomoides typus, Lethrinusnebulosus, L utjanus H neolatus, L. argen-timaculatus, etc. Tht rocky areas of theWadge Bank (12 000 km^ and Quilon Bank(3 300 km^) harboured rich concentrations.Probably with increased effort for theseresources there, the production can be increased considerably. Although accurate estimates are not available, it appeares thatabout 40 000 - 6 0 000 tonnes of additionalmajor perches can be caught annually.FLATHSHES: T he averag e an nual prod uction was about 30 000 tonnes (5.7%), withparticular abundance in Kerala, Karnataka,Maharashtra and Tamil Nadu. These wereabundant in muddy and /or sandy bottom up toabout 80 m depth belonging to gen era such asCynoglossus, Psettodes, Pseudorho mbus,Bothus, Paraplagusia, etc. and exploited bytrawl nets, gill nets and other anisanal gears.A marginal increase of about 8 000 tonnes ispossible from the present fishing rang e.LIZARD nsHES: This gro up , compos edmosl\y oiSauridatumbil&n6 S. undosquatnis,accounted for abo ut 21 000 tonnes (4% )

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Maith, June 19921 OVCR VII-W O.N DbMiatSAI. rrNHSIl RHSOURCES

annually, mostly from Kerala, 'lamii Nadu,Karnataka and Maharashira, and was exploited by Uawl nets, hoo ks and lines and gillnets. A further marginal increase of about6 000 lonnes is possible.GOAinsiins: With an annual yield of8 000 tonnes during 1985-89, this gruup hasthree imporiant genera in India, Upeneus,Parupeneus and Mulloidichthys. These wereexploited by trawls and traditional gears mostly in Tamil Nadu, Andhra Pradesh, Kerala,Kamataka and M aharashua.

TIIREADITNS: Tw o gen era of po lyn em ids ,Eleuthcronema and Polynemus were responsible for the bulk of threadfins, with anaverage annual production of 6 500 tonnes,mostly in Gujarat, Maharashtra and AndhraPradesh.EELS: These were particularly abundant in Gujarat and Maharaslitra, the

average annual production, composed of COAJ-gresox talabanoides and Muraenesoxcincreus was 5 000 tonnes.Resources currently overexpioitedCATFlSHES: Ac counting for an ann ualaverage of 50 630 tonnes (9.8%), this groupis abundant in muddy ground s of 20 - 70 mdepth zone and migrates both horizontally(parallel to the co ast) and vertically. Amongabout 23 species under three genera, Tachy-surus, Osteogeneiosis and Balrachocephalus,only about 10 are commcrcialiy exploitableand harvested by trawls, gill nets, hooks andlines, purse seines and a wide variety of uadi-tional gears. They migrate fiom north to southduring southwest m onsoon and south to northduring the post monso on; and are abundant inGujarat, Maharashtra, Kainataka, Kerala andnortheast coast. B ut, large-scale exploitationby purse seines along Kamataka has resultedin mass destruction of the brooders and torccruitmcnt-overfishing in Kamataka andKerala in the recent pas t Since the resource is

migratory and as most species have a long lifespan, the above impact is reflected in otherparts of the countrj' also. The average prod uction has declined from about 8 060 tonnesduring 1979-83 to only about 4 070 tonnesduring 1984-87 (James et al. 1989). An estimate revealed that within the twomonths of Septem ber-Octo ber every year,on an average, more than 8 million egg s and-early juveniles of T. tenuispinis (13 tonnes)are destroyed. This led to a considerablereduction in the recruitment to the commercialcatches during 1986 and 1987.

THE wi irre ns H: Also called bu tterfish,Laciarius lactarius is an other reso urce, thathas been overexpioited in the inshore watersby modem u^awling. Although disu-ibutcd allalong the coastline, it has been supportingnotable fisheries along the southwest andsoutheast regions. On an all India basis, thefishery assumed importance from the late fifties and reached a peak production of 25 334tonnes in 1985. Thereafter, there was a steadydecline, reaching 6 685 tonnes in 1989, although slightly recovering later. The declinewas so marked in the southwest coast that ina single centre, Vizhinjam alone, the production which stood at 62.4 tonnes in 1970 hadfallen to a meagre 0.1 tonne in 1979 (Lutheret al. 1982).

CERTAIN OTHER RESOURCES: P u b l i s h e dinformation and unpu blished data have shownthat the dura (Polydactylus indicus, Polynemus hepiadactylus), karkara (Pomadasyshasta), kolh (Ololithoides brunneus), ghol(Protonibea diacanthus) and warn (Con-gresox talabanoides, Muraenesox cinereus)have dwindled in production in Gujarat andMaharashtra (Kagwade 1989, Bcnsam andMenon 1991). The whale shark Rhincodontypus found usually in Gujarat waters hasbeen overexpioited and has reached to an endangered status (James 1991). The flatheadPlatycephalus maculipinna is another species

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BENSAM [VoL39,Nal.2that has been overexploited along thesouthwest coast. Studies have indicated thatthe major cause for the decrease in productionis its indescriminate exploitation and massdesti'uction of its spawners and juveniles fromthe breeding arid feeding grounds by coastaltrawlers (Bensam and Menon 1991).Scope for urther increasing productionAs per the recent reports and estimates(G.O.I. 1991). an increase of about 103 000tonnes of elasmobranchs, 65 000 tonnes ofpink perch, 63 000 tonnes of catfish. 60 000tonnes of major perches, 21 000 tonnes oflizard fishes, 4 000 tonnes of silvcrbcllies,goat fishes, etc is possible beyond the 50 mdepth of the continental shelf. Also, considerable quantities of bull's eye (Priacanthusspp), black ruff (Centrolophus niger), driftfish (Ariomma indica), etc are available fromwithin the shelf region of 50 m to still deeperwaters up to 200-500 m. According to Bandeet a/.(1990), the potential yield of b ull's eyefrom the Indian E E Z is around 79 000 tonnes.The exploratory surveys of the FORV SagarSampada have revealed that high fishableconcentrations of the pink perch are availableoff southwest coast, amounting up to a CPUEof 2.67 tonnes during June-July, 3.5 tonnesduring July-August and 8.1 tonnes duringSeptember-December in certain locations.The CPUE for bull's eye has been up to 4.9tonnes inAugust. 1.5 tonnes in September; fordriftfishup to 8.0 tonnes during February; andfor lizard fishes up to 750 kg during June(James and Filial 1990).

It is thus obvious that in addition to themarginal increases of certain resources fromthe presently exploited region up to about50-70 m depth, the sole alternative for increasing demersalfinfishproduction is fromthe region beyond the presently exploitedzone. For their judicious exploitation and

utilization, it is essential to identify and improve upon the designs of thecrafts and gearsto be used in space and time.For optimum utilization and streamlineddevelopment of anyfishing ndustry it is essential to pay adequate attention to post-harvest and utilization aspects, both in th^domestic and export m arkets. This is especially so in the case of demersal finfishes whichgenerally fetch lower prices than many otherquality fishes. Modernization of the existinginfrastructure strength and processingfacilities have to be undertaken for landingand berthing of vessels, freezing plants,processing units, etc. One reason for thehesitation of entrepreneurs to enter into deep-seafishing s the non-availability of reliabledata on the economics of the operations,which is essential to provide specific and accurate data to ward off uncertainties. Since theoperations are capital-intensive, the projectsshould be cleared without delays; timely funding is needed; and marketing strategies shouldbe made viable. Similarly, for most of thedemersalfinfishesand their products, there isa lack of adequate storage and processingfacilities, resulting in a distinct gap for theirinternal marketing. Also, the fish transportation system is poorly developed, resulting invery litUe of the fish harvested reaching theinterior markets, inspite of heavy demand.Hence, the precious effort and time of theindustry have not brought adequate economicreturns.

The domestic marketing for demersal fin fishes needs immediate attention and expansion, incorporating product - innovation and.development of value-added products. Thelow-priced sciaenids, soles, lizardfishes,flat-heads, bull's eye, driftfish,etc need attentionfor developing composite fish products, improving the methods of drying, etc. Unless thisvoid is filled up, a part of the fishing effortsfor demersal finfishes will remain unac-108


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Maidi. June 1992] OVERVIEW ON DEMERSAL HNFISH RESOimC ES

counted for. Outlining all these aspeci|s, theCMFRI (1991) prepared a draft document ona Technology Mission for achieving muchmore development of the marinefishing ndustry as a w hole.With the large-scale introduction of

mechanized trawling, several environmentalproblems and stock-recruitment hazards to inshore fisheries have come up. The scrappingof the shallow bottom has trampled anddamaged the juvenile population of demersalfinfishes such as pomfrets,flatfishes,perches,sciaenids, lizard fishes, e tc. as well as of thebottom non-edible biota (stomatopods,echiurids, sipunculids, sponges, molluscs,echinodcrms, etc) which are the major basisfor the food of many edible groups. Since thetrawling operations are continuous throughout the year, day in and day out, these haveresulted in little opportunity for the biota toreestablish and replenish at the bottom. Thus,the damage to the demersal habitatof finfishesis much more severe than what is estimated.The destruction of juvenile demersal finfishes has been taking place without any control. According taBcnsam and Menon (1991),of the estimated 10% of trashfishproductionof trawlers in Kerala, 70% are juveniles andsubadulls of commercially important demersal fishes belonging to about 60 species. Asthe cod end mesh size of the trawl nets is about1.5 - 2.5 cm, the juveniles caught arc alsoproportionately high, especially during thebreeding and nursery seasons of monsoon andposUTionsoon. From these facts it is quite obvious that the shallow coastal waters up toabout 50 m depth are the spawning and/ornursery grounds of most demersalfinfishes.Acomparison of the catch data by trawlersoperating in shallow and deeper localities hasrevealed that the juvenile abundance washigher in shallow areas up to 30 m depth andgradually decreases in the depths of 30-5 0 m

and beyond. From these facts, it is obviousthat one primary cause for the depletion ofonce thrivingfisheriessuch as for ghol, hoth.karkara, warn, whitefish,flatheads,etc is thelarge-scale destruction of their juveniles. Thedeleterious effects of large-scalepurse seiningon the catfish stocks is another aspect that hasto be reckoned.

In view of these, it is high time that weidentify the resourced/species which are underthreat of destruction, wherever necessary;monitor the species-wise stock - recruitmentpattern, sustainable yield, spawner andjuvenile components; delimit the areas andseasQns of trawling and purse seining; regulate the cod end mesh size of trawl nets toabout 3.5 cm; ban coastal trawling at least upto 30 m depth; encourage the use of vertical,high opening type of nets for avoiding benthicsweeping and juvenile desuuction; closepurse seining in certain areas and breedingseasons of the resources; wilfully avoid thecapture of breeding shoals; educate the fishermen to be eco-friendly and resource-friendly;audit the environment at periodic intervals forconservation and rational management; andinvolve all the people concerned in theseaspects.

REFERENCESBande V N, Mcnon N G and Balachandran K. 1990.

Studies on Ihe distribution and abundance of b ull'sey e {Priacanthus si>p.)\n\i\e E EZ of India. CentralMarine Fisheries Research Institute. Proceedings ofFirst Workshop on Scientific Results of FOR VSagar Sampada held at Cochin in June 1989. pp233-38.

Bcnsam P and Mcnon N G. 1991. The endangered, vulnerable and rare demersal marine finfishes of India.Paper presented at Ihe National Seminar on En-dangered Fishes of India. National Bureau of FishGenetic Resources, Allahabad, and Nature Conservators, Muzi'.afamagar.

CMFRI. l99l.Technotogy Mission for Marine FisheriesDevelopment.Central Marine Fisheries ResearchInstitute, Coch in.

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BENSAM [V d. 39. No. 1, 2G.O.L 1991. Report of the Working Group on

Revalidation of the Potential Marine FisheriesResources of the Exclusive Economic Zone of India.Ministiy of Agriculture, Government of India,New Delhi.

James P S B R. 1991. Endangered, vulnerable and ratemarine fishes and animals. Paper presented at theNational Seminar on Endangered Fishes


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Documents

Overview of Present Status of Future Direction for Demersal Finfish Fisheires