For the management of mollusc resources, knowledge of various population parameters and exploitation level of the population of wedge clams are needed. Population dynamics on wedge clam, Donax scortum is still unknown in Asia. FAO-ICLARM Stock Assessment Tools (commonly known as FiSAT) was used for calculating population parameters of this species. The specimens of D. scortum were collected from Padukere sandy beach at monthly intervals from February 2009 to January 2010. Asymptotic length (Lα) was 70.88 mm and growth coefficient (K) was estimated at 0.64 year−1. The sizes attained by D. scortum were 33.51, 51.17, 60.49, 65.40, 67.99 and 69.36 mm at the end of first, second, third, fourth, fifth and sixth years of age, respectively. Density of clams ranged from 2 ind. m−2 (June, July and August) to 8 ind. m−2 (December). Biomass (total weight) of clams ranged between 10.084 g m−2 (August) to 185.100 g m−2 (December). Total mortality (Z) for D. scortum was 3.20 year−1. Natural mortality (M) and fishing mortality (F) were 0.64 year−1 and 2.56 year−1 respectively. Exploitation level (E) was computed as 0.80, indicating that the fishery of D. scortum in the coastal waters of Karnataka is overexploited.

Wedge clam, Donax scortum occurrence was studied from February 2009 to January 2010 in Padukere sandy beach, Karnataka (India). The following biological parameters were measured in 2367 individuals of the wedge clam, Donax scortum: length, breadth, width, total weight, shell weight, wet meat weight, dry meat weight and number of clams. The calculated linear equation of length-breadth and length-width relationships were B = 3.5968 + 0.5421L and W = 0.8191 + 0.4345L respectively. The length-total weight, length-wet meat weight, length-dry meat weight and length-shell weight relationships were 0.0001414L3.0224, W = 0.0000037L3.5204, W = 0.0000011L3.4513 and 0.0000852L2.9912 respectively. The values of correlation coefficient for different shell dimensional relationships were very close to unity. It was clear from the study that the most ideal period for clam harvest was April, June and December, especially when condition index was maximum. Length showed a strong correlation with silt and clay. Dry meat weight was negatively correlated with air temperature. Shell weight showed positive correlation with length, breadth, width and dry meat weight, and abiotic parameters, silt and clay. Condition index was positively correlated with electrical conductivity, whereas it was negatively correlated with dissolved oxygen. It showed a strong positive correlation with salinity. Seasonal fluctuation of condition index in D. scortum was probably related to reproductive activity. The harvesting of wedge clam could be carried out considering the maximum sustainable yield without over-exploitation