Extension of Rotifer (Brachionus Plicatilis) Inclusions in the Larval Diets of Mud Crab, Scylla Paramamosain (Estampodor, 1949): Effects on Survival, Growth, Metamorphosis and Development Time

The study evaluated the effects of extended dietary inclusions of rotifers (Brachionus plicatilis) on the survival, metamorphosis rate, growth and development time in the larvae of mud crabs (Scylla paramamosain). The five most commonly published feeding regimes of mud crab (S. paramamosain) larvae were selected and tested by including rotifers onto them. Mud crab larvae in the first feeding regime were fed exclusively with Artemia nauplii (control or regime A), while those in feeding regimes 2, 3, 4 and 5 were fed rotifers starting from zoea 1 (Z1) to various development stages of mud crab larvae whereas feeding with Artemia nauplii was commenced from the Z2 stage until the end of the trial (megalopa stage). The results of the larval feeding trial for 24 days of culture showed the progressive decrease in survival of the larvae in all feeding regimes. Extended inclusion of rotifer feeding until Z5 stage resulted in significantly higher survival than in the control from 18 day after hatching onwards. Larval survival was negatively correlated (R2 from 0.78 to 0.90) with the rearing time; however, different feeding regimes had no significant effect on this correlation. Extending inclusion of rotifer feeding until the Z3, Z4 and Z5 stages resulted in higher percentages of megalopa metamorphosis than in regime control, but did not significantly impact development time, carapace width, body length and wet weight of megalopa.Â