Habitat-related predation on juvenile wild-caught and hatchery-reared red drum Sciaenops ocellatus (Linnaeus)

We examined the patterns of habitat-specific mortality for newly settled re d drum (Sciaenops ocellatus) using an experimental mesocosm approach. Exper iments were designed to analyze prey vulnerability and fish rearing-type (w ild-caught or hatchery-reared) in estuarine habitats of varying structural complexity including marsh (Spartina alterniflora Loisel), oyster reef (Cra ssostrea virginica Gmelin), seagrass (Halodule wrightii Aschers), and nonve getated sand bottom. We used two different predators, pinfish (Lagodon rhom boides Linnaeus) and spotted seatrout (Cynoscion nebulosus Cuvier). For bot h predators, vulnerability of wild-caught red drum was significantly lower in structurally complex habitats such as seagrass and oyster reef; the high est vulnerability was associated with the nonvegetated bottom. This habitat effect was not apparent for hatchery-reared prey. In trials using a combin ation of both rearing-types, there was no significant habitat effect on pre y selection, but hatchery-reared red drum suffered higher overall mortality than wild-caught fish from pinfish predators. In these trials, spotted sea trout did not select for either prey type. Differences we observed in prey vulnerability were likely caused by behavioral differences between wild-cau ght and hatchery-reared red drum. Our results reinforce the conclusion that structural complexity in estuarine habitats increases survival of newly se ttled fishes. Our data also suggest that hatchery-reared red drum may be mo re vulnerable to predation than natural fishes, and that survival of stocke d fish may be enhanced through habitat-related behavior modification. Publi shed by Elsevier Science B.V.