Graphic by U.S. Fish & Wildlife Service
St. Marys River
The St. Marys River continues to be of special concern to the U.S. Fish and Wildlife Service and the Department of Fisheries and Oceans Canada. The river has the potential to contribute large numbers of parasitic-phase sea lampreys to northern Lake Huron. Prior to 1998, the sea lamprey population in the St. Marys River had been largely uncontrolled due to the large volume of water flowing through it and the presence of large lakes within the river system.
During 1998-2001, the lampricide granular Bayluscide was applied to about 2,200 acres of the river in U.S. and Canada - areas of dense populations of sea lamprey larvae. Assessments using a specially modified pontoon boat and deepwater electrofisher coupled with GPS showed these applications removed about 45% of the population of larvae in the river.
Assessments are performed to determine which areas within the river require lampricide control and to monitor the effectiveness of those treatments. With recent advances, including a deepwater lampricide and alternative control technologies, the sea lamprey population has been greatly reduced from populations present in the mid 1990’s. These advances have contributed to the restoration of healthy fish stocks in northern lakes Huron and Michigan.
