Theme D: Developing optimal release strategies
42. IMPLEMENTING A NEW STOCKING PROGRAM IN UNCHARTERED WATERS: DEVELOPING OPTIMAL RELEASE STRATEGIES FOR WINTER FLOUNDER IN MASSACHUSETTS AND NEW YORK, USA
Elizabeth A. Fairchild
University of New Hampshire, Department of Biological Sciences, Durham, NH, 03824, USA
elizabeth.fairchild@unh.edu
While winter flounder enhancement research has been ongoing in New Hampshire for more than a decade, only approximately 35,000 juveniles have been released in total. The goal of these past projects has not been to initiate large-scale releases. Rather, our “responsible approach” has been to develop the processes needed to successfully enhance winter flounder by answering key questions about optimal release strategies with small releases (< 2,000 fish) in the event that large-scale stocking efforts occur. A new multi-state regional winter flounder stocking project has begun in Massachusetts and New York which will test these processes. The first part of this project is to formulate optimal release strategies; a comprehensive study currently is underway to do this in areas where little historic data exist using what we term “ecosystem analyses.”
For each region (East Hampton, NY and Martha’s Vineyard, MA), two estuaries are being studied for a 12 month period to determine the spatial and temporal distribution of the wild winter flounder population, potential predators, and prey species, as well as other important parameters (water temperature, salinity, dissolved oxygen, substrate). These estuaries were chosen, in part, because historically winter flounder were abundant in them, and they appear to have appropriate habitat for juvenile winter flounder.
These “ecosystem analyses” will guide the decision-making process in determining the best site in each region for pilot-scale stockings of winter flounder. These sites will be areas with appropriate conditions for juvenile winter flounder. These areas also must be below carrying capacity; they must have excess resources to support additional fish –food availability exceeding wild winter flounder needs. The best season(s) and site(s) for releases will be the times and locations with low predator abundance yet high prey abundance. Optimal size-at-release for cultured winter flounder will be determined by the predator- prey complexes at the proposed release site during the proposed release season. Survival in fish increases with size; smaller fish typically have lower survival than larger individuals due to the wide range of predators capable of eating them. However, hatchery costs increase with fish size due to the increase in space, feed, and labor. The best size-at-release will be a compromise between these two conflicting demands. Knowing which predators are present (and what size flounder they can eat) will determine the most successful size-at-release for pilot-scale stockings. By using ecosystem analyses in unknown potential release sites, reasonable and responsible guidelines can be calculated for new stocking programs.
Call For Papers