With 64 miles of Lake Michigan shoreline, 26 lakes and ponds, and four streams, fish are an important resource of Sleeping Bear Dunes National Lakeshore. There are 76 known fish species within the park. Some species, which were once common such as the lake sturgeon and lake herring are now on Michigan’s List of Threatened Species. Other native species once common, such as the brook trout and yellow perch, are in decline.
The introduction of exotic fish, either accidentally or purposely, is a remarkable story of environmental impact. Sea lampreys were able to access the upper Great Lakes only after the completion of the Welland Canal around Niagara Falls. They reached Lake Michigan by 1936 and soon devastated the native lake trout. The alewife, a fish from the Atlantic coast, was first noted in Lake Michigan in 1949. Since then it has dominated the environment accounting for an estimated 50% of Lake Michigan’s fish biomass by the 1960s. They have reduced native fish populations of perch, lake herring and chubs. During some years, great numbers of alewife die and wash up along the beaches in wind rows. One purpose for the introduction of salmon to Lake Michigan in the 1960s was to feed on the alewife.
