Understanding Reservoir Systems with Experimental Tests of Ecological Theory: A Prescription for Management
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Date
1996
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Abstract
Enhancement of angler opportunities in U.S. reservoirs necessitates creative management approaches. One such approach, which builds on a successful manager–researcher partnership, derives from understanding reservoir food webs through experimental tests of ecological theory (in this case, the trophic cascade hypothesis). An explicit example involves predator control of gizzard shad Dorosoma cepedianum, a species that dominates Ohio reservoirs, suppresses zooplankton, outcompetes larval life stages of sport fishes, and regulates community composition. In pond experiments, hybrid striped bass Morone saxatilis x M. chrysops can control age-0 gizzard shad, increasing zooplankton density and size, thus improving conditions for sport-fish recruitment. Combining pond results with small-scale laboratory experiments, field values of crustacean zooplankton size and productivity, and gizzard shad density, we generated an ecologically based conceptual model of recruitment environments across Ohio reservoirs smaller than 500 ha. With this model, managers can apportion their limited resources according to prioritized management goals. To attain these goals, additional features associated with the community, such as anglers (as top predators with unique characteristics), and watersheds (as determinants of reservoir water quality) must be included. Whole-system manipulations, in which management actions permit hypothesis testing (i.e., adaptive management), combine with small-scale experiments to yield an understanding that provides a quantitative foundation for effective reservoir management.
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Keywords
trophic cascade hypothesis, Ohio reservoir food webs, age-0 gizzard shad, hybrid striped bass, crustacean zooplankton, reservoir fish recruitment management
Citation
Stein, Roy A.; Bremigan, Mary T.; Dettmers, John M. "Understanding Reservoir Systems with Experimental Tests of Ecological Theory: A Prescription for Management," American Fisheries Society Symposium, v. 16, 1996, pp. 12-22.