Behavioral performance of wild-caught and laboratory-reared red drum Sciaenops ocellatus (Linnaeus) larvae

Abstract

Laboratory- and hatchery-reared fish often differ morphologically, physiologically, and/or behaviorally from wild-caught fish. We compared the behavioral performance of laboratory-reared red drum ( Sciaenops ocellatus) larvae to that of wild-caught larvae to examine potential differences due to rearing and to validate interpretations of experiments on lab-reared larvae. Routine swimming speed and the timing and magnitude of startle responses elicited by acoustic and visual stimuli were measured on three size classes (developmental stages) of larvae (8, 13, and 27 mm TL). Mean routine swimming speeds were greater in wild larvae compared to reared larvae at 8 mm TL, but 27-mm wild larvae exhibited lower speeds than reared larvae at 27 mm TL. In acoustically mediated startle responses, wild larvae of all sizes were more responsive, took less time to respond, and in the 8-mm size class, had greater response distances and speeds than reared larvae. In visually mediated startle responses, 8- and 13-mm reared larvae had greater response distances and durations, while 27-mm wild larvae were less responsive than reared larvae. These observations suggest caution when inferring behavioral capabilities of wild larvae based on observations of lab-reared red drum and that behavioral deficiencies due to rearing may reduce survivorship of lab-reared red drum upon release into the environment.