Population dynamics of Ruditapes decussatus (Mollusca: Bivalvia) in the Gulf of Gabes, Tunisia

Ruditapes decussatus is one of the most abundant bivalve species in the Gulf of Gabes. Its current exploitation status and management are becoming a major concern for the fishing industry in Tunisia. The aim of this study was to ascertain the population structure, growth, mortality and exploitation rate of R. decussatus. Length-frequency data were analyzed for the estimation of population parameters using the FiSAT Iota Iota software. Asymptotic length (L infinity) infinity ) was found to be 59.95 mm and growth coefficient (K) was 0.70 yr-1.-1 . The growth performance index (cp') was 3.40. Total mortality (Z) was estimated by the length-converted catch curve at 2.01 yr-1,-1 , fishing mortality (F) at 1.02 yr-1,-1 , and natural mortality (M) at 0.99 yr-1.-1 . The exploitation rate (E = 0.51 yr-1)-1 ) indicated that the fishing pressure on the R. decussatus population was relatively high. The condition index was used as a tool to identify optimal and sustainable harvesting periods which correspond to the period between April and June.