A meta-analysis on the effects of temperature and salinity on Scylla spp. larvae

Mangrove crabs (Scylla spp.) are recognized as economically valuable and important crustaceans in the aquaculture industry. This includes S. olivacea, S. paramamosain, S. tranquebarica, and S. serrata. However, aquaculture production of these species continues to depend on wild-caught seedstock due to the low success rates of hatchery operations. This highlights the need to explore alternative Scylla species to reduce pressure on wild populations. Moreover, further improvements in hatchery management techniques for larval rearing are necessary, building on the foundation established by previous studies. Accordingly, this study evaluates the effects of water temperature and salinity on the survival of S. olivacea, S. paramamosain, S. tranquebarica and S. serrata larvae through meta-analysis. A search strategy following PRISMA guidelines was used, and the literature search involved ScienceDirect, Google Scholar, Scopus, and Wiley Online Library. A total of 321 studies were determined for S. olivacea, 657 for S. paramamosain, 551 for S. tranquebarica, and 969 for S. serrata. Further screening resulted in 6 articles for S. olivacea, 8 for S. paramamosain, 7 for S. tranquebarica and 7 for S. serrata. From these, 4 articles for S. olivacea, 6 for S. paramamosain, 5 for S. tranquebarica, and 4 for S. serrata were included for meta-analysis and meta-regression using R. Results showed that temperature has a mild effect, while salinity has a greater effect on the survival of mangrove crab larvae. It is then suggested that the temperature levels should be 30 °C for S. olivacea, 28–30 °C for S. paramamosain, 30.5 °C for S. tranquebarica, and 29 °C for S. serrata. Similarly, the salinity levels should be 30 ppt for S. olivacea, 28–31 ppt for S. paramamosain, 31 ppt for S. tranquebarica, and 28–33 ppt for S. serrata. Moreover, high confidence intervals and heterogeneity were observed across all species, which may be attributed to the limited number of studies and differences in sampling size and experimental design. These findings are essential for developing optimized and standardized larval rearing protocols to enhance hatchery production and reduce reliance on wild stocks.