The Future of Mussels in the Cannon
Of 297 native freshwater Mussels in North America, 213 are listed as endangered or threatened (Williams et. al, 1993). Reasons for extinction include habitat destruction from dams, channel modification, siltation, and introduction of non-native species.
Mussels in the Cannon River have demonstrated considerable resilience through the age of the pearl rush which decimated populations. They also demonstrate an ability to survive in water of increasing turbidity due to erosion. However, their ability to survive will continue to be tested as erosion continues. It is possible however; that recent changes in construction regulations designed to prevent erosion will improve the water quality for the mussels.
Mussels in the Cannon River may soon have to compete with the exotic species, the Zebra Mussel (Dreissena polymorpha). Introduced to the Great Lakes from Eastern Europe, this species is highly competitive and has been known to attach to other mussel species to keep them from feeding. Boaters in and around the Great Lakes have inadvertently assisted this species' infiltration of the area by transporting mussel larvae in ballast water etc. While our study was being conducted, Zebra Mussels were found in the nearby St. Croix River. This discovery indicates that the Mussels may become part of the rest of Minnesota's waterways soon.
Although the outlook for mussels in the Cannon River may appear bleak, residents of the watershed have begun to take a greater interest in the water quality of the river. Thanks to the Cannon River Watershed Partnership, people are becoming more aware of the issues affecting the river today. Through further education, more people will learn the importance of mussels as indicator species of the overall health of the river. This heightened awareness could ultimately preserve the mussels in the Cannon River.
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