Journal of the Marine Biological Association of India

Fishery, biology and yield estimates of Portunus sanguinolentus off Chennai

Volume 54 Issue 1

S. Lakshmi Pillai and P. Thirumilu doi: 10.6024/jmbai.2012.54.1.01671-09

Abstract

The fishery and stock characteristics of the dominant species of crab, Portunus sanguinolentus was studied along the Chennai
coast. The annual crab landings during the period 1998-2007 ranged from 236 t to 1,628 t with the catch rate fluctuating between 0.78 kg/h and 2.01 kg/h. The carapace width of P. sanguinolentus in the fishery was 41-165 mm for females and 41-155 mm for males. Females were dominant throughout the period of study, the overall sex ratio 1:1.41. Spawning was observed during October to April with peak spawning in December and January and peak recruitment in May, July and August. The estimated growth parameters are: females L∞= 168.6 mm, K=1.3/yr-1; males L∞ = 161.9 mm, K=1.0/yr-1 and mortality parameters are: females Z = 4.3, M = 1.2, F = 3.0; males: Z = 3.2, M = 1.1, F = 2.1. Thomson and Bell yield prediction analysis gave the MSY as 536 t against the present annual average yield of 529 t that can be obtained by increasing the effort by 20% from the present level. As the increase in yield is marginal, it is suggested to maintain the effort at present level. Since crabs have high consumer demand and are an important ecological entity the resource needs proper management for its sustenance.

Keywords

P. sanguinolentus, Chennai, fishery, growth, mortality, yield estimates.

Date : 27-06-2012