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Keppner, S. M., and T. Czapla, 1996. Comparisons of Biodiversity in Harbors With and Without Ruffe (Gymnocephalus cernuus), U.S. Fish and Wildlife Service Abstract from The Sixth International Zebra Mussel and Other Aquatic Nuisance Species Conference, Dearborn, Michigan, March 1996 Comparisons of Biodiversity in Harbors With and Without Ruffe (Gymnocephalus cernuus)The waters of the Great Lakes basin represent a dynamic, changing ecosystem. Throughout history, the introduction and successful establishment of nonindigneous aquatic species have induced direct and indirect effects on native organisms, populations, and communities. The indirect effects of species invasions at the community level may include alterations in species abundance and diversity. The ruffe, Gymnocephalus cernuus, first identified in North American waters in 1987, is believed to have been introduced into the St. Louis River in the early to mid-1980s. Like the zebra mussel, ruffe are believed to have been introduced through ballast water discharge. Since its discovery, surveillance programs have continued to track range expansion and monitor species abundance and diversity in areas where ruffe have already colonized as well as in areas where ruffe are likely to colonize. Surveillance efforts have targeted shipping harbors throughout the Great Lakes due to their vulnerability to introduction through inter- and intra-lake shipping activities. Trawl data from dredged shipping channels in the St. Louis River were used as the basis for species abundance and diversity in harbors already colonized by ruffe. Harbors surveyed on Lake Erie provided the basis for comparison as locations without ruffe populations. Analyses provide an indication of potential impacts to the diversity of harbor fisheries due to the introduction of ruffe.
Key Words: Ruffe, Ecological_interactions, Basic_biology |