Population dynamics of the Asian green mussel <i>Perna viridis</i> (L.) from St. Mary’s islands off Malpe, India

1659-1666Size range of mussels in the population varies from 6.1 to 133.2 mm. Von Bertalanffy growth equation for length was Lt = 136.9 [1-e -0.42 ( t+0.38)]. Growth performance index (Φ') was estimated as 3.896. Total mortality (Z) of the regime was 1.18 year−1. Natural mortality (M) and fishing mortality (F) rates were 0.42 year−1 and 0.76 year−1 respectively. Total mortality based on mean size in the sample for the whole population ranged from 0.5380 (October 2005) to 2.2492 (December 2004). Cohort size was reduced by 50% within 6 months after settlement. Maximum and minimum densities of mussels were 5,404 no.m-2 (December 2004) and 1,744 no.m-2 (October 2005) respectively and the average was 3,105 no.m-2. Biomass (total weight) of mussels varied from 8,910 g.m-2 (November 2004) to 37,745 g.m-2 (December 2005) at the study site during the study period. Average biomass was 22,754 g m-2. Biomass values (total weight, wet weight, dry weight and shell weight) increased with the increasing growth of mussels. Specific production (C) ranged from 0.0488 (June 2005) to 0.1318 (January 2005). High specific production was recorded during post-monsoon season and low values during pre-monsoon season. Maximum length recorded (Lmax) was 133.2 mm