Mud crab, Scylla tranquebarica (Fabricius, 1798), crablet grow-out in lined ponds with different stocking densities to support soft-shell crab production

Abstract

Crab stocking densities in brackish water ponds can influence crab growth rate, survival, and production volume. This study aimed to determine the optimum grow-out stocking density for Scylla tranquebarica crablets reared in lined ponds to supply the soft-shell crab industry. Three stocking density treatments (1, 4, and 8 ind./m2) were applied to crablets reared in lined ponds for 90 days. The crablets were fed low-value fish (Leiognathus equula) at an initial rate of 100% of total body weight for two weeks, reduced to 3% toward the end of the study. Crablets stocked at 1 and 4 ind./m2 had a significantly (p < 0.05) higher net growth (NG) and daily growth rate (DGR) than crablets stocked at 8 ind./m2. Deformed crabs were also most common at the highest stocking density. The intermediate stocking rate achieved moderate survival and feed conversion rates, with the highest crab production volume (19.65 ± 0.10 kg/100 m2) and net income (6845.60 US$/Ha/2 crops/year). Based on these findings, a stocking rate of around 4 ind./m2 is recommended for the grow-out of S. tranquebarica crablets in lined ponds.