Population dynamics of greater lizardfish,Saurida tumbil from Pakistani waters

Growth and mortality parameters of greater lizardfish saurida tumbil (bloch,1975) from the pakistani waters were estimated using length frequency data which were collected from five research trawl surveys during 2009 - 2010. the pooled data of both sexes of s. tumbil consisted of 824 pair of length weight and 2320 length frequency data. the length-weight relationship were at a = 0.011,b = 2.931. the von bertalanffy growth function parameters were l∞ = 48.30 cm (fl) k = 0.320 year-1 using elefan method and t0 = - 0.786. based on the growth parameters the total,natural and fishing mortality were estimated at 1.160,0.716 and 0.444 year-1,respectively. the yield per recruit analysis indicates that,when tc was assumed to be 2,fmax was estimated as 1.25 and f0.1 at 1.15; when tc was assumed to be 1,fmax was estimated as 1 and f0.1 at 0.9. currently we assume that the age at first capture was about 1 year and fcurrent and was 0.444,therefore fcurrent was smaller than f0.1 and fmax. this indicated that the current fishery is in a sustainable condition. when using the gulland formula biological reference point fopt was equal to m (0.716). the current fishing mortality rate of 0.444 year-1 was lower than the biological reference point. the exploitation ratio (e) was estimated at 0.382 year-1. in the view of the above results we may assume that the stock of s. tumbil fishery from pakistani waters is in a sustainable state. copyright 2015 zoological society of pakistan.