Dynamics of the gold-spotted grenadier anchovy (Coilia dussumieri) stock along the northwest coast of India

Abstract

The Coilia dussumieri along the northwest coast of India (18° 38’ N to 21° 68’ N) was studied using the Beverton and Holt analytical model, Ricker’s stock—recruitment relation and the surplus production models of Schaefer and of Fox for 190—’85. The length growth parameters: L, annual k and t0 for 1963—’64 wer? found to be 27.20 cm, 1.10 and 0.001 year respectively while during 1981—’85 L ranged from 22.20 cm in 1985 to 26.52 cm in 1981, annual k from 1.07 in 1985 to 1.49 in 1984 and t0 from —0.58 year in 1982 to —0.02 year in 1981. The weight growth parameters: W, annual k and t0 were estimated to be 18.50 g (1963—64) and 20.50 g (1981—85), 0.93 (1963—64) and 1.23(1981—85) and 0.01 year (1963—64) and —0.15 year (1981—85) respectively. The lengths at first capture (1,) and recruitment 1r were found to be 8.75 cm and 3.50 cm respectively and their corresponding t, and tr were estimated to be 0.42 year and 0.08 year respectively. Total mortality (Z) ranged from 3.20 in 1985 to 7.31 in 1982, natural mortality (M) from 2.02 in 1985 to 2.46 in 1984 and fishing mortality (F) from 1.19 in 1985 to 5.20 in 1982. Cohort analysis indicated maximum F at the 112+ age (=2.16) in 1981, 1+ age during 1982 (=5.20), 1983 (=1.23) and 1984 (=4.21) and 1 112+ age in 1985 (=1.19). In the premechanization period (1960—’70) the MSY for the exploited (by indigenous fishing) portion of the underexploited stock was 5,356 t (analytical model), 6,322 t (Schaefer model) and 6,309 t (Fox model). The MSY for the fully exploited stock in the mechanised period (1971—84) was 17,237 t (analytical model), 16,805 t (Schaefer model) and 20,489t (Fox model). The MSY estimated by the stock—recruitment model for the 1960—84 period was found to be 24,451 t. The prediction model indicated an estimated catch of 22,540t in tho year 2000 if the effort remained constant.