COMPARATIVE BEHAVIOUR AND SURVIVAL OF HATCHERY-REARED VERSUS WILD SUMMER FLOUNDER (PARALICHTHYS DENTATUS)

G.T. Kellison, D.B. Eggleston, J.S. Burke - 2000

Can. J. Fish. Aquat. Sci. 57: 1870-1877
Abstract:

We describe the use of laboratory trials to compare substrate-specific behaviour and susceptibility to predation of hatchery-reared (HR) versus wild summer flounder (Paralichthys dentatus) juveniles. HR fish spent significantly more time swimming in the water column than wild fish and took significantly longer to become cryptic on the benthos than wild fish, regardless of substrate type. In predation trials with a blue crab (Callinectes sapidus) predator, naïve HR fish were significantly more susceptible to predation than wild fish. Antipredator-conditioned HR fish were significantly less susceptible to predation than naïve HR fish but significantly more susceptible than wild fish, irrespective of substrate. The modified behavioural patterns and increased susceptibility to predation of HR individuals observed in this study indicate that flounder reared in psychosensory-deprived hatchery environments may be poorly equipped to survive in natural habitats; they also indicate that it may be possible to mitigate detrimental behavioural patterns by exposing naïve HR fish to natural stimuli before release into natural environments. These results have important implications for stock enhancement, suggesting that stocked organisms are more likely to achieve postrelease survival if they are conditioned with natural stimuli prior to release into the wild.

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