Using Ecosystem Analyses and Hatcheries to Enhance Fish Populations Responsibly

Stocking fish to augment natural populations is not a new technology, yet in many cases successful stocking strategies are defined retroactively by comparing different release strategies. Evaluating different scenarios pre-release, as opposed to post-release, may provide a more comprehensive and resource-saving mechanism to determine optimal release strategies. Several modeling programs are available for this purpose and can generate different stocking scenarios, depending on the input variables and desired outcome. However, in order for these programs to be effective, modelers must have valid input data for the release area(s). If a potential release area has not been the subject of other studies, or historic data are not available, modeling will not be fruitful. Alternatively, thorough pre-release sampling, termed ecosystem analyses, can generate meaningful information for stock enhancement programs and can resolve questions concerning best release site (both macro- and micro-locations), season, release time-of-day, size-at-release, release magnitude, as well as highlight potential problems that may be encountered. By incorporating ecosystem analyses results into both field and hatchery components of fish stockings, enhancement success increases. A case study on Martha’s Vineyard, Massachusetts involving winter flounder, Pseudopleuronectes americanus, stock enhancement will be discussed.