On the fishery and biology of the crab Portunus sanguinolentus (Herbst) along the South Kanara coast

Abstract

The fishery of the crab Portunus sanguinolenttis along the South Kanara coast extends generally from, December to May. The catches of the species at Mangalore during 1979-80, 1980-81 and 1981-82 are estimated respectively at 102.3 t, 100.2 t and 57.0 t. The catches at Malpe during 1980-81 and 1981-82 are at 65.9 t and 44.1 t, respectively. The carapace-width-body-weight relationship does not differ between sexes. Spawning takes place throughout the season, with peaks in February and April-May. Males are in excess of females, differing though not significantly from the expected 1 : 1 ratio. Fecundity is estimated to be ranging between 0.03 million (in a specimen of 83-mm carapace width) and 0.07 million (in a specimen of 113-mm carapace width), suggesting a positive relationship between size and fecundity. The L^, and e"'' values are found respectively at 173 mm and 0.7 in males and 163 mm and 0.75 in females.