Population dynamics of Meretrix casta (Gmelin, 1791) along Thoothukudi, Gulf of Mannar, India

The present study was performed to understand the population dynamics and current status of Meretrix casta stock along the southern coast of Tamil Nadu, India. The estimated value for asymptotic length, growth coefficient and growth performance index was 5.41 cm, 0.77 year ^-1 and 1.35, respectively. The value of t₀ was recorded to be -0.07529 years. The instantaneous rate of total mortality (Z), fishing mortality (F) and natural mortality (M) was estimated at 2.58 yr ^-1 , 0.98 yr ^-1 and 1.60 yr ^-1 , respectively. Virtual population analysis showed that fishing mortality was higher in the largest group (41 – 50 mm). The current exploitation rate (U) and exploitation ratio (E) were recorded as 0.35and 0.38, respectively, which was lower than the E _opt= 0.5 criterion. The present study indicated that the exploitation of M. casta is near to optimum level and suggests further scope to increase the fishing effort for the optimum harvest of M. casta from the studied region. However, regular monitoring programs should be implemented to sustain these resources.