Increasing trends in capture of fish juveniles and sub-adults: A red signal for fishery resources

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1 Indian Journal of Geo-Marine Sciences Vol. 45(6), June 216, pp Increasing trends in capture of fish juveniles and sub-adults: A red signal for fishery resources Sher Khan Panhwar 1* Noureen Farooq 1, Nazia Qamar 1 & Khawar Parvez Awan 1,2. 1 Center of Excellence in Marine Biology, University of Karachi-7527, Pakistan 2 Directorate of Inland Fisheries, Sindh, Hyderabad, Pakistan [ sk.panhwar@uok.edu.pk] Received 21 July 215; revised 29 July 215 In this paper, we have figured out tendency of sweeping juveniles and sub-adults of commercially important fish stocks in northern Arabian Seacoast of Pakistan. The specimens were collected from Zero point Badin (ZPB), Hyderi fish jetty (HFJ), Clifton Karachi (CFK) and Karachi Fish Harbour (KFH) from August 214 to March 215. These fishes mainly caught with purse seines, gill nets, pelagic and demersal trawls and beach seines. An average 4t/day undersize catch (trash) have been recorded from ten fish landing sites in Karachi with an average 15t/day have been landed at KFH solely. Some 562 individuals belonging to the (38) families and (67) species were procured. The composition of fish families by weight from the KFH was categorically Platycephalidae 2%, Engraulidae and plotosidae 12% respectively; from HFJ, family Sciaenidae comprises of 26%, Dasyatidae 23% and Muraenesocidae 13%; from ZPB, Gobiidae 31%, Soleidae 14% and Polynemidae and Sciaenidae 12%; and from CFK, Clupeidae 49%, Penaeidae 28% and Trichiuridae 1%. The diversity index H' was estimated for four sampling sites the highest diversity (3.29) and the lowest (1.93) for KFH and CFK respectively, whereas highest species richness R=8.49 from HFJ followed by KFH, R=5.24 and the lowest R=2.28 from CFK. Comparing similarity index KFH and HFJ shared highest number of similar species. It is assumed from the consistent landing of juvenile and sub-adults of various valuable fish stocks is clear indication of population deterioration and seems appropriate monitoring and mesh size regulation are beyond the priorities of fishers and mangers. [Key words: Juvenile capture, biodiversity, un-sustainability, fishery management] Introduction The world s remaining commercial fish stocks has already been overhavested 1,2,3 because of unsystematic capture of undersize fishes and juveniles of commercially important species and other non-target organisms that are unintentionally captured called as bycatch. Today, the activity of bycatch is corrupting marine ecosystem and has become an important conservation issue 4,5,6. The Indus delta comprises of seventeen major and several minor creeks along with widespread mud flats and mangroves forests are considered as the nursery grounds for numerous juveniles of fish and shellfish species. These shallow water bodies are easily targeted by the fishers and are under severe fishing pressure on juveniles. In terms of the conservation and management, there are several unanswered questions are needed to be answer such as need to know exactly effects of towed gears on the seabed, impacts of fishers who use dynamite or poisoning coral reef ecosystem and effects of fishery waste on the population of scavenging fishes. In Pakistan, about 9% of marine catch handled at Karachi fish Harbour of which more than 6% of landing consists of bycatch 7. Due to the uncontrolled fishery, use of illegal gears and mesh size has resulted severe threats observed to the stocks of the queen fishes in Pakistan 8. In view of the unsustainable situation of the wild fish stocks, this study was aimed to evaluate potential consequences of the increasing trends in capture of juveniles of the commercially important species and consequences of prohibited fishing gears. Material and Methods Fish sampling was made from four fish landing sites, Zero point Badin, Hyderi fish jetty (HFJ) Korangi and its adjacent landing areas, Clifton

2 PANHWAR et al.: INCREASING TRENDS IN CAPTURE OF FISH JUVENILES AND SUB-ADULTS 785 (CFK) and Karachi fish harbour (KFH) from August 214 to March 215. In the laboratory, species were identified using gross morphometric and meristic counts using FAO species identification sheets 9 and classified according to the species, genus and families. Each individual was measured to its total length (cm) using fish measuring board and the total weight (g) was taken on an electronic balance. Diversity estimations diversity, richness and evenness were calculated with: Diversity H index H ' pi. Ln pi,... i 1,... S... (1) H ' Diversity index (N1) = N 1 e (11) 1 N 2 Diversity index (N2) = c (11) richness (R1) = richness (R2) = Evenness (E1) = Evenness (E2) = E 1 E S - 1 R1 Ln (N) R2 H ' H ' H Ln S S' S N 2 max H e S CV ' STDEV Mean (12) (13) (14) (15) Coefficient of variation = Whereas; S=number of species; ni= number of individuals of a species; N=number of individuals of all species and pi=ni/n. Undersize catch landed at ten jetties and harbour information was obtained from the FCS. The % composition of species by weight wt = individual weight of each species. composition by weight was calculated and the species diversity index, species richness and species evenness were subsequently analyzed. Results Some 562 individuals belonging to 38 families and 67 species were identified during the entire study period. An average 4t per day production of trash fish recorded from ten fish landing sites in Karachi whereas 14kg trash have been recorded at Karachi fish harbour (KFH) solely followed by 325 at Jam Alam small jetty in Korangi and landing record of rest of the each jetties, Ibrahim Hyderi, Haji Ibrahim tale wala, Jamote Jetty, Hassan Ramoon Jetty, Reheri goth, and Jatt Jetty, Bangali Jety, charam jetty comprises of about kg each (Fig. 1). Average per/day juveniles capture (Kg) Karachi Fish Harbour Ibrahim Hyderi Jam Alam, Korangi Haji Ibrahim tale wala Jamote Jetty Hassan Ramoon Jetty Fish landing sites Reheri goth Jatt Jetty Bangali Jetty Charam Jetty Fig. 1. An average per day weight of the undersized catch landed at various landing sites of Sindh coast. Estimated fish diversity from four main sampling sited denoted that the highest Shannon Weiner diversity index H' 3.29 was at KFH whereas the lowest H'=1.93 estimated from Clifton Karachi. The more fish species present in a sample of HFJ, so the highest species richness (R) were weighed up from HFJ R=8.49 followed by KFH R=5.24 and the lowest species richness computed from CFK R=2.28 (Table 1). Table 1. Biodiversity parameters (H' index=shannon Weiner diversity index; c-index=simpsons diversity index, R=richness; N=diversity indices and E=evenness) estimated in the present study. Location H' index c- index R1 R2 N1 N2 E1 E2 ZPB HFJ CFK KFH CV A dendrogram plotted against species collected from four sampling centers, showed highest similarity between HFJ and KFH specimens, whereas, moderate and lowest similarity noted in the population collected from KFH-CFK and CFK-ZPB respectively (Fig. 6). A number of juveniles of dominant and economic important species in attendance at four fish landing sites, from Badin Johnius dussumieri (Sciaenidae) 12%, cynoglosus puncticeps (Cynoglosidae) 4%, Zebrias guagga (Soleidae) 14%, Liza subviridis (Mugilidae) 7%, Boliopthalamus dussumieri (Gobiidae) 31%, and others contributing 24% (Fig. 2), from Hyderi fish jetty Johnius belangerii, Johnius glaucus, Johnius aneus (Sciaenidae) 26%,Solea elongate (Soleidae) 4% and others contributed 33% (Fig. 3), from Clifton Karachi Parapenaeopsis stylifera (penaeidae) 28%, Johnius carutta (Sciaenidae) 5%, Sardinella albellaa,

3 786 INDIAN J. MAR. SCI. VOL. 45, NO. 6 JUNE 216 Sardinella mystax and Hilsa kelee (Clupeidae) 49% and others contributed 5% (Fig. 4). The dominant fish species by weight contributed of the total trash fish at Karachi fish harbour was Grammoplites suppositus (platycephalidae) 18%, Plotosus lineatus (Plotosidae) and spp (Engraulidae) 12%, spp (Pomadasyidae) 9%, Saurida undosquamis(synodontidae) 7%, Decapterus russelli and Carangoides uii (Carangidae) 6%, and spp. (Ariidae) 5%. It is evident from the (Fig. 5) that Grammoplites was highest followed by Plotosus whereas Lepturacanthus, Saurida and mystax were captured at the same rate. Weight (g) Carangoides uii Coeiella Conger cinereus Decapterus Grammoplites Lactarius Leiognathus Lepturacanthus Megalaspis Parascolopsis Plotosus Polynemus Rastrelliger Saurida Scorparnidae Secutor Sphyraena mystax Upeneus Fig. 5. Estimated weight of the fishes examined in the trash obtained from Karachi fish Harbour. 8 6 Weigth (g) 4 Weigth (g) Acanthopagrus latus tenuispinis Bagrus gulio Boliopthalamus dussumerii Catla catla Channa maruilus pucticeps Eleuthernema tetradactylum Euryglossa orientalis Hyporhampus dussumieri Johnius dusumerii Liza subviridis Oreochromis mossambicus Sctophagus argus Silago sihama Terapon theraps vitriostris Fig. 2. Number of species anchored in trash at the fish landing site lagoons, Badin, Sindh. Weight (g) Anodonstoma jella thalasinus Bothus Caranx para Collectteichtcys Drepane Euryglossa Hilsa kelee Himuntura walga Ilisha Johnieops Johnius Johnius glaucus Legocephlugus Leignathus Liza megalopter Megalaspis Muraenesox Muranessax Narconi timlei Nematulosa Pennahia Platycephalus Rabdosargus Sauirda Scatophagus Solea elongata Terapon theraps mystax Zebrias Fig. 3. Estimated weight of the fishes examined in the trash obtained from Hyderi fish landing site Hilsa kelee Sardinella albella Sardinella melanura mystax tenuispines Eleuthernema tetradactylum Trichiurus lepturus Johinus carutta Leiognethus daura Fig. 4. Estimated weight of the fishes examined in the trash obtained from Clifton fish landing site. Liza parisa Parapeneopsis stylifera Zebrias guagga Fig. 6. Hierarchal cluster analysis for four respect sampling centers. Discussion On the basis of the outputs, this study has established a plausible gesture that majority of economically important fish species are often go into trash that is not trash in real but juveniles, these illegal fishing activities are beyond the normal fishery practices. The small mesh size gears can harm juvenile stocks and most of the fish species often caught prior the maturation would eventually harms food recruitment, food chain, web and ultimately ecosystems wherever the practices happens. The collected data from four key fish landing sites asserted that how ichthyodiversity is dwindling and the juveniles are integrated in trash fish from coastal, estuarine and creeks. It is an understandable that KFH was highly divers with a Shannon-Wieners diversity index compared with other sites. In Pakistan, about 9% landing were traced from KFH of which 6% by catch consisted 7. In our study we estimated that an average per day landing of so called trash was higher at Karachi fish Harbour comparing the other

4 PANHWAR et al.: INCREASING TRENDS IN CAPTURE OF FISH JUVENILES AND SUB-ADULTS 787 sites this may be due permitting large number of fishing vessels and uncurbed fishing gears. Generally by-catch mainly composed of those fishes that captured by trawl and purse seines transmitted on land a proposed above 15 days, one month or more. Basically fishermen first sort fish catch on board, fishes that are targeted species an kept them in ice and others non-target species or unideal size being captured through small mesh size net, treated badly and considered as trash. This trash become that portion of the catch which has a low consumer preference and no market value; send to the industries for fish meal production 16, this trash fish also known as industrial fish 17. For the reason that it has now turn into a source of employment for fishermen, so it has formed a business for them. A similar situation is reported from Ghana, West Africa, the trash fish altered into valuable trade and has become a wealth for their local fishermen 18. Comparing similarity index KFH and HFJ shared highest number of similar species. Besides this, heavy fishing pressure on juveniles is turning down stocks abruptly which have an effect on species richness and also distressing biodiversity that is the symptom of variety of life in an ecosystem. Different species assemble the richness of an area and low evenness is a sign of a few species dominant in that area. It is suggested that the ecosystem productivity and stability might be enhanced by species richness 19,2. Generally marine wild resource greatly support to the millions of people around world in the form of as food and marine biodiversity play an imperative role in maintaining the marine ecosystems, if a trophic level eliminate from the food web system it would be immensely impact on the animals of top trophic levels. The consistent landing of juvenile and subadults that negatively impact on fish populations and seems appropriate monitoring and mesh size regulation are beyond the priorities of fishers and mangers. We therefore, recommend that rules and regulation must not be violated and prevention of undersize stocks assured by the mangers otherwise most important stocks will be swiped out in near future. Some implications for management are proposed a) There is need to establish replenishment / recruitment programs to compensate loss b) formulate mariculture schemes to provide alternative livelihood to the fishers c) start awareness programs d) to establish finfish and shrimp hatcheries for seed production. Acknowledgement The authors greatly appreciate assistance of Mr. Nasir Bunery, of the fishermen cooperative society (FCS) for providing important information about trash fish landings. References 1 Pauly, D., Christensen, V., Dalsgaard, J., Froese, R. & Torres, J. Fishing down marine food webs. Sci., 279, (1998), Pauly, D., Christensen, V., Guénette, S., Pitcher, T.J. & Walters, C.J. Towards sustainability in world fisheries. Nature, 418, (2), Worm, B., Barbier, E.B., Beaumont, N., Duffy, J.E., Folke, C., Halpern, B.S., Jackson, J.B.C., Lotze, H.K., Micheli, F., Palumbi, S.R., Sala, E., Selkoe, K.A., Stachowicz, J.J & Watson, R. Impacts of biodiversity loss on ocean ecosystem services. Sci. 314, (6) Harrington, J.M., Myers, R.A & Rosenberg, A.A. Wasted fishery resources: discarded by-catch in the USA. Fish and Fisher., 6, (6), Lewison, R.L., Crowder, L.B., Read, A.J & Freeman, S.A. Understanding impacts of fisheries bycatch on marine mega fauna. Trends in Ecol. Evol. 19, (4) Hall, M.A., Alverson, D.L., & Metuzals, K.I. Bycatch: Problems and Solutions. Mar. Poll. Bull. 41, () Pitcher, T.J. Estimating Compliance with FAO Code of Conduct Article 7 fisheries management: Pakistan In: Pitcher, T J. and Daniela Kalikoski, Safe conduct: ten years fishing under the UN code. Fisheries Centre, University of British Columbia (5). 8 Panhwar, S.K., Qamar, N & Jahangir, S. Fishery and stock estimates of Talang queenfish, Scomberoides commersonnianus (Fam: Carangidae) from the Arabian Sea, Coast of Pakistan. Pakistan Jr. Agri. Sci. 51, (214), Fischer, W. & Bianchi, G. FAO species identification sheets for fishery purposes, western Indian Ocean. FAO Press, (1984) Rome, pp. 1 Shannon, C.E & Weaver, W. The Math. Theory of Comm. Univ. Illinois Press, Urebana, (1963), 367 pp. 11 Peet. R.K. The measurement of species diversity. Ann. Rev. Ecol. & Syst. 5, (1974) Margaleef, R. Information theory in ecology, Gen. Syst. 3, 1958, Menhinick, E.F. A comparison of some speciesindividuals diversity indices applied to samples of field insects. Ecol. 45, (1964),

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