The effect of temperature, salinity, eyestalk ablation, and limb removal on growth and survival of juvenile paddle crab, Ovalipes trimaculatus (Brachyura: Portunidae)

Abstract

Crustacean growth in nature is affected by hormonal processes and natural stressors. For aquaculture purposes, paddle crab, Ovalipes trimaculatus (De Haan, 1833), juveniles were subjected to experimental eyestalk ablation, limb removal, and a combination 3 × 3 temperature and salinity conditions. Relative lifetime in captivity (RLC), molting success (MS), molting interval (MI), growth in terms of size and weight after molting (SI and WI), specific growth rate in size (SGRs) and weight (SGRw), and hepatosomatic index (HS) were evaluated in eight replicate groups of crabs for each treatment (one crab per tank). RLC was significantly lower in eyestalk-ablated crabs than in those subjected to limb removal and to control conditions (no organ removal, 13 °C, salinity of 33); it was significantly higher in crabs held at a salinity of 30 vs those maintained at 33 and 27. Combinations of 16 or 19 °C and salinity of 30 provided the optimal conditions of growth in size and weight. Results suggest that control of temperature and salinity can improve growth and survival of juveniles in captivity. However, organ removal did not promote molting in captivity, likely to the detriment of survival and physiological condition. Findings from the present study highlight the importance of carefully selecting conditions to rear this valuable commercial crab to promote its aquaculture in the region.