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Busiahn, T. R., 1996. Ruffe -- A Case Study, U.S. Fish and Wildlife Service Abstract from The Sixth International Zebra Mussel and Other Aquatic Nuisance Species Conference, Dearborn, Michigan, March 1996 Ruffe -- A Case StudyThe first nonidigenous species to be declared a nuisance warranting a control program under the U.S. Nonindigenous Aquatic Nuisance Prevention and Control Act (Act), is the ruffe, a Eurasian fish that colonized the Duluth-Superior harbor in Lake Superior, apparently transported to North America in the ballast water of an ocean-going ship in the early 1980s. Studies show that the ruffe population has increased to several million individuals, while several co-habiting fish species have declined. Surveillance sampling has detected range expansion through migration along Lake Superior’s south shore, and by ballast water transport in commercial lake vessels from Duluth-Superior to the Canadian port of Thunder Bay and to the U.S. port of Alpena in Lake Huron. Coordinated multi-agency management responses to ruffe have met with limited success, mostly due to lack of technologies to control free-ranging organisms in open aquatic ecosystems. The States of Wisconsin and Minnesota attempted to increase predator fish populations in hopes of limiting ruffe population growth. The U.S. Fish and Wildlife Service and National Biological Service attempted to develop and apply chemical treatment techniques to eradicate ruffe in river mouths. These attempts appear to have failed. The Great Lakes maritime industry, in consultation with government agencies, instituted a voluntary ballast water management plan to reduce the risk that ruffe would be transported; the success of this plan is uncertain since ruffe were found in Lake Huron. Actions taken to educate the public and to regulate bait harvest from ruffe-infested waters appear successful to date in preventing transport of ruffe in commercial bait tanks and anglers’ bait buckets. Control activities and supporting studies have been coordinated since 1993 under a "Ruffe Control Program" developed under authority of the Act. The goal of the program, revised since ruffe were found in Lake Huron in 1995, is to prevent or delay their further spread through the Great Lakes and prevent their spread to other inland lakes and watersheds. This goal is supported by eight objectives developed through extensive consultation among government agencies and the private sector. Technological difficulties in implementing the control program have been exacerbated by policy conflicts regarding possible chemical treatments, and by shortcomings in the ability to predict economic impacts of ruffe expansion. The concept of "integrated pest management" (IPM) receives general support for application to ruffe, but IPM requires a variety of control techniques and reliable estimates of economic damage, neither of which are available. Two conclusions appear certain: 1) ruffe are highly successful colonizers of North American waters that will cause significant adverse effects through competition with native fishes, and 2) preventing future invasions by nonindigenous species is preferable to trying to control them after they become established.
Keywords: Ruffe, Prevention, Policy |