Effects of habitat structure and salinity on growth and survival of juvenile mangrove red snapper Lutjanus argentimaculatus (Forsskal, 1775)

摘要

Mangrove Red Snapper (Lutjanus argentimaculatus) is a large, palatable fish that has become increasingly valuable foraquaculture in South East Asia. Unfortunately, the bulk of current mariculture of L. argentimaculatus depends almost entirely onfingerlings collected from the wild, since hatchery-raised fry are regarded as inferior by fishermen. Wild Mangrove Red Snapperspawn on offshore reefs, but their larvae occupy coastal lagoons and estuaries. In this study, we examined some of the factors(habitat structure and salinity) associated with the natural recruitment habitat of L. argentimaculatus to determine whether theymight play a role in the perceived superiority of wild-caught fry. We found statistically significant relationships between survivaland salinity, and between somatic growth and habitat structure, but no interaction between the factors. Juvenile L.argentimaculatus survived best at moderate (17ppt) salinities, with fresher water (10ppt) providing better outcomes than moresaline (25ppt) conditions. We found also that juveniles grew best when provided with hard, complex structures (rock piles andmangrove roots), rather than in tanks without such structures. Here, we have demonstrated two simple environmental factors thatimprove survival and growth of juvenile L. argentimaculatus and may provide a substantial boost to the performance of hatcheryrearedfish.