The present study aimed to assess the effect of initial planting size classes (Experiment 1; 22, 24, 26 and 28mm) and initial stocking density (Experiment 2; 200, 300, 400 and 500 specimens/m²) on growth performance and survival rate of clam Ruditapes decussatus. Simultaneously two field experiments were conducted in the intertidal zone of Akarit (gulf of Gabès) over 31 months. Selected natural clam were sown in hard plastic net bag (0.5m2) and buried into the soft bottom sediment. For the growth and survival evaluation, shell length and wet weight were measured individually every month throughout the experimental period.
At the end of growth trial, results demonstrated that initial seed sizes did not have a significant effect on clam growth and survivorship; in fact, clams of different initial size classes reached the legal commercial size (35 mm) in the same time period and average length did not differ significantly among treatments (P<0.05; ANCOVA). Also, results demonstrated that initial densities of 200 and 300 ind/m², did not have a significant effect on clam growth and survival rates. However, for the other initial densities, growth and survival rates were significantly dropped.
