Potential for Predation by Fishes to Impact Zebra Mussels Dreissena polymorpha: Insight from Bioenergetics Models
ENGINEER RESEARCH AND DEVELOPMENT CENTER VICKSBURG MS ENVIRONMENTAL LAB
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Bioenergetic modeling provided insight into the potential for fishes to impact zebra mussel Dreissena polymorpha populations by predation across river and lake systems in eastern North America 13 deg latitude x 12 deg longitude. Food consumption modeling suggested that fishes in southern latitudes consumed up to 100 percent more food than those in northern systems. Much variation in food consumption was the result of differing water temperature regimes, which presumably dictated the bioenergetic demands of fishes. The potential for fishes to impact zebra mussels was also influenced by the standing crop of different species and the fish community as a whole. Fish community structures followed predictable patterns along both longitudinal and latitudinal gradients. Multivariate analyses indicated a tendency for central and southern U.S. systems to contain greater standing crops or biomasses of fishes likely to consume zebra mussels. Though analyses indicated northern systems had greater biomasses of some potential zebra mussel predators, net biomass increases of these species was not great enough to offset the decreases in food consumption due to cooler annual water temperatures. This study generally supports the premise that fishes in more southern including central U.S. waters have inherently greater potential to impact zebra mussels because of community composition and bioenergetics. Our simulations provide a partial explanation of why zebra mussel invasions have not been as rapid and widespread in southern U.S. waters compared to the Great Lakes region.