Population dynamics of sciaenid Johnius macrorhynus (Pisces/Perciformes/ Sciaenidae) from Bombay waters

Abstract

von Bertalanffy's growth equation was used to describe growth of Johnius macrorhynus (Mohan). The values estimated were L(infinity) = 331 mm, K = 0.5415 (annual) and t0 = -0.07876 y and W(infinity) = 323 g. This species reached 143, 224 and 270 mm at the end of I, II and III years of its life respectively. The average total, natural and fishing mortality coefficients were 2.87, 1.18 and 1.69 respectively. Exploitation rate and ratio were 0.555 and 0.588 respectively. Yield per recruit study showed that at the present level of age of capture (t(c)) of 0.9261 years and fishing mortality (F) 1.69 the Y(w)/R is 17.71 g. Average total and standing stocks were estimated as 2286.50 and 750.89 ton respectively as compared to the present average yield of 1269.01 ton.