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Early detection of non-indigenous fishes in Lake Superior
Citation:
Schloesser, J., H. Quinlan, AND J. Hoffman. Early detection of non-indigenous fishes in Lake Superior. Presented at Upper Midwest Invasive Species Conference, October 29 - 31, 2012.
Impact/Purpose:
Not applicable
Description:
Invasive species pose a serious threat to the ecological stability of the Great Lakes warranting continual monitoring for the arrival of new species. Three locations in Lake Superior were identified as “high risk” for new introductions: St. Louis River near Duluth, MN, Upper St. Marys River near Sault Ste. Marie, MI/ON, and Thunder Bay, ON harbor. Each location was sampled using a US EPA protocol developed in the St. Louis River. Sampling occurred during August and September 2010 and 2011 by boat electrofishing, fyke nets, and bottom trawling. Annually, at the St. Louis River twenty sites were sampled with fyke nets and electrofishing each, and ten bottom trawls. The Upper St. Marys River and Thunder Bay were sampled with fifteen samples of each gear type because the optimal gear allocation to maximize the number of species detected was unknown. Our analysis indicated that a gear mixture of 40% fyke nets, 40% electrofishing, and 20% trawls would maximize the number of species detected at the St. Louis River and Thunder Bay. The Upper St. Marys River should be sampled with 40% fyke nets, 20% electrofishing, and 40% trawls. In order to detect 95% of the total estimated species richness, a total of 102, 116, and 90 samples were needed for the St. Louis River, Upper St. Marys River, and Thunder Bay, respectively. Additional sampling during 2012 will provide a more robust evaluation of a location specific sampling design.