Stock assessment of the Indian scad, <i style="">Decapterus russelli</i> (Ruppell, 1830) from Mumbai waters

Abstract

Present study consists the Growth, mortality and the stock assessment of <i style="">Decapterus russelli</i> . ‘L_∞’ was estimated as 277 mm and ‘K’ as 1.237/year. The t_o<b style=""> </b>estimated by VBGF plot was – 0.3443 year. Growth in length of <i style="">D. russelli</i> described following von Bertalanffy growth equation as, L_t = 277[ 1-e ^{-1.237{t-(-0.3443)}}]. Longevity was estimated to be 2.42 years. Total mortality rate (Z), natural mortality rate (M) and fishing mortality (F) were estimated to be 6.66, 2.1 and 4.56 respectively. In this study, Z/K was found to be 5.38 indicating that the stock of <i style="">D. russelli</i> is presently mortality dominated in Mumbai waters. Exploitation rate (U) was calculated as 0.6838 and the Exploitation ratio (F/Z) as 0.6847. Thompson and Bell long-term prediction analysis indicated that there is no decline in yield of <i style="">D. russelli</i> even if the fishing effort is doubled. Present level of fishing has no deleterious effect on the fishery of <i style="">D. russelli</i>