Abstract

The success of stock enhancement programs is contingent upon survival of hatchery-reared progeny. In this study, we investigate the effect of pre-release exposure on the survival of a marine finfish, red drum (Sciaenops ocellatus). Red drum larvae were collected from a Texas Parks and Wildlife Department (TPWD) hatchery and reared with and without the presence of natural vegetation (Spartina alterniflora) for either 10 or 20 days High-speed video was used to analyze a suite of prey-capture performance and anti-predator response variables at day 28 (~30 mm TL) and day 38 (~40 mm TL). Multivariate testing indicated that overall performance of juvenile red drum increased with age but rearing habitat did not enhance survival skills. Univariate contrasts showed that timing and distance of key response variables (e.g. maximum gape, time to maximum gape, gape cycle duration and time to maximum velocity) increased significantly with age. Although the multivariate models indicated that exposure to natural vegetation did not influence overall performance, univariate contrasts showed that time to reach maximum velocity was faster for individuals reared in vegetation; however, these fish also had a shorter reaction distance to predators and took longer to capture prey. Our results demonstrate that feeding performance and anti-predator response increases with age, while exposure to natural vegetation does not appear to afford any obvious benefits. Work addressing the effect of predator exposure on red drum performance is currently underway and will also be discussed in the context of supplemental stocking

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