Carangid fishery and yield per recruit analysis of Caranx carangus (Bloch) and Caranx leptolepis Cuvier and Valenciennes from Tuticorln waters

Abstract

An estimated annual average catch of 205.8 t of arangid were landed during 1981-83 by traditional fishing units. gmmise at& composition of carangid was okrvod. Deptbwise variation in the abundance ot arangid was obswved from the catch rats of these traditional gears. During 1984-87, an -timated a?nual average mtch of 12563 t of carangid wae landed in which the trawl net units IsnM 11848 t and drift gill net units 715 t. nough the abundane of carangid varied from year to year, in general, it appears there is one prrmounoed abundance during July to Novemkr and another lesg pmnowoed during January to April. Th annual average species composition of trawl net landings wa also studied. Based on the eatcb in numhr, e€forl and lengtb frequency data. tbe estimated growth parameters of Curanx leptolepis are L 213 mm, K 1.4283 and b -0.0151 and of C. mmngus are La. 498 mm, K 0.7689 and o -0.0455. Estimated gmwth in weight of there -eg couid be okained from the length weight relatiomhip given. 'he natural mortality ooemdeat M Is estimated to be 2.19 for C. &prole& and 1.1 8 for C, carangus h the life spn Tmu of these specim. Tlx total mortality d e i e n t Z varied from 4.33 in 1986-87 to 8.33 in 1984-85 for C. rSpoo&ph with an average of 6.10 in trawl net. For C. carangus, th Z varied from 4.48 in 1985-86 to 9.69 in 1984-85 with an average of 654 in trawl nd and in drift gill net i t was 2.80 in 1986-87 to 4.77 in 1985-86 with an avaage of 3.92. The yield p m i t lor 3 different WK ratios obtained for these two species indicate that C. leflokpis is not exposed to higher fishing presjure as in the erase d C. cnrangus by trawl mt and the efW of trawl met may be inaeased further to match the F- to realise enhanced pmductioa of this e e s . Whereas, in the case of C. cmangrrs further inaease in trawl net cffwt may not be favourable unless the age at first apture is inat%& by inrxeasing the cod end mcrsh size which is not praaticai as the main aim of trawl net is to exploit some other resources likc prawns a d C, carangus is only a bycatch. However. exploitation of this species by drift gill net may be i m s e d by inmasing the mesh size fwthw lo enhattoe the age at first acepa as he prevailing age at first wpture is only 0.28 yr, wbereas a optimum age of exploitation is 1.W yrs.