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Keppner, S. M., J. McClain, T. R. Busiahn, G. Johnson, 1997. Surveillance for Ruffe in the Great Lakes - An Overview, New York Sea Grant Institute -- Reprinted from the ‘Great Lakes Research Review’ with permission of the New York Sea Grant Institute and the Great Lakes Research Consortium. Surveillance for Ruffe in the Great Lakes - An OverviewAbstract - The establishment of nonindigenous aquatic species is a perturbation that challenges resource managers in the Great Lakes basin to understand the dynamics of the present system, and predict patterns for the future. The effects of invasive species and their eventual distribution are difficult to predict. Surveillance programs are used by managers as a means of identifying newly established populations, tracking range expansions, assessing the impacts of introduced species on native populations, and evaluating control or management strategies. The ruffe, Gymnocephalus cernuus, like the zebra mussel, is believed to have been introduced to the Great Lakes through ballast water discharge. Since its discovery, surveillance programs have continued to track range expansion and monitor species abundance in areas where ruffe have already colonized as well as in areas where ruffe are likely to colonize. In addition to conducting field surveys, the education of public water users has been instrumental to increasing surveillance efforts. In several cases, recreational anglers were first to report the presence of ruffe at new locations, findings that were later verified with fish sampling gear. Communication with the maritime industry has guided surveillance efforts to shipping ports where ruffe may colonize via ballast water transport. The probability of detection by surveillance sampling of new colonies of ruffe appears to be rather high, because ruffe are highly selective toward favorable habitat at low population densities. Western Lake Superior surveys have documented the natural movement of ruffe, changes in fish species abundance, and the ability of ruffe to become the dominant fish species. Preliminary results suggest declines in native fish populations following the successful establishment of ruffe. Surveys in areas where ruffe have not yet invaded provide information regarding native or currently existing populations, without which it is difficult to determine the effects of an invasion. The proactive management approach exemplified by the Great Lakes Ruffe Surveillance Program, conducted by the U.S. Fish and Wildlife Service and the Ontario Ministry of Natural Resources, provides a model response to species invasions. Entire Paper |