Fishery and stock assessment of Metapenaeus dobsoni (Miers, 1878) off Chennai

Fishery, growth, mortality and maximum sustainable yield of Metapenaeus dobsoni (Miers) off Chennai during 2004-07 is presented in the article. Metapenaeus dobsoni contributed 16.5% to the total penaeid shrimps landed during 2004-2007 at Chennai Fisheries Harbour. Total length range was 36-130 mm for females and 41-120 mm for males, overall sex ratio being 1:1.5 (M:F). Size at 50% maturity (69 mm) was attained in five months. Longevity was estimated to be 1.8 months. Length weight relationship for females and males pooled was 0.0000062L super(3.02.) Growth parameters estimated for sex pooled data are 131 mm (L sub(oo)) and 1.68 (K, annual). Linearised catch curve gave total mortality coefficient (Z) of 7.93. Fishing (F) and natural mortality (M) are 5.86 and 1.79 respectively with exploitation ratio (E) of 0.74. Thomson and Bell yield prediction analysis showed that the present fishing has reached the maximum sustainable yield, but the maximum sustainable economic yield is attained at the F-factor 0.6. Hence it is suggested to decrease the present fishing effort by 40% to sustain the fishery and get maximum revenue.