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Hatchery rearing environment and age affect survival and movements of stocked juvenile lake sturgeon





  • E. A. BAKER

James A. Crossman, 601, 18th Street, Castlegar, BC, Canada, V1N 2N1 (e-mail:


Abstract  Considerable uncertainty exists over the relative merits of alternative supplementation strategies for lake sturgeon, Acipenser fulvescens Rafinesque. Numerous supplementation prescriptions have been advocated, largely in the absence of data, focusing on perceived impacts of levels of genetic diversity of progeny collected using different collection methods, and probabilities of survival relative to the size or age of fish released. The hypothesis that collection method, hatchery rearing environment and size/age at the time of release do not influence survival and movements was tested. Acipenser fulvescens gametes and juveniles were collected using three methods and reared in a stream-side hatchery along the natal stream and in a traditional non-natal hatchery environment. Acipenser fulvescens were released into the Upper Black River, Michigan at 8, 13, and 17 weeks of age. Higher rates of recapture were found for juvenile sturgeon reared in the stream-side hatchery than the traditional hatchery for the releases at 8 and 13 weeks. Recapture rates and dispersal distances were significantly greater for fish stocked at 17 weeks than for fish released at earlier ages. Large body size was negatively correlated with timing of movements across all ages indicating that survival may be enhanced by releasing individuals at night. Results indicate that supplementation protocols for A. fulvescens should be developed on a system specific basis and demonstrate the importance of hatchery-rearing environment when fish of younger ages are released.