Evaluating the culturing performance of two-skinned mud crabs<i> (Scylla</i><i> paramamosain</i> ) using intermolt and mature crabs in various eyestalk ablation and gender conditions

Abstract

A thorough investigation into the effects of crustacean eyestalk ablation across different genders is crucial for optimizing aquaculture practices. This research was conducted from June to September 2023, with two separate experiments to assess how eyestalk removal and the gender of mud crabs (Scylla paramamosain) affected the performance of raising double-skinned crabs using intermolt and mature crabs. Both experiments utilized a completely randomized design with three replications in rectangular tanks (a bottom area of 0.3 m2). Crabs were divided into four eyestalk ablation groups (no ablation, right ablation, left ablation, and bilateral ablation) in experiment 1, while experiment 2 focused on right eyestalk ablation crabs and categorized them into three gender groups (males, females, and mixed-sex). The animals were stocked at a density of 20 individuals m-2 and were fed trash fish at a rate of 5% of their wet body weight throughout the experiments. The results showed that eyestalk ablation did not significantly affect overall yields. However, it improved the specific growth rate (SGR), the time needed to form double-skinned crabs (duration), and the feed conversion ratio (FCR). The right ablation group showed the most notable improvements. The bilateral ablation group showed improvements in FCR but had the fewest benefits in SGR, duration, and survival rate (SR). Additionally, gender factors had a minor effect on duration, with the shortest time recorded for the female group. Both male and mixed-sex groups showed improvements in FCR but experienced a decline in SR, with a significant reduction in the male group. Based on these findings, it is recommended that right eyestalk ablation in intermolt and mature female mud crabs is the most effective strategy for producing double-skinned crabs under the conditions studied.