Dams and other barriers are having a significant effect on fish habitat in the Upper Midwest. More than 3,700 dams have been constructed on Wisconsin’s warm water streams. Similarly, there are 2,500 listed dams in Michigan and likely a similar number that are not in the dam safety database for that state. In the Lake Michigan watershed alone, dams, culverts, and road crossings that impede fish migration have reduced nearly 19,000 miles of accessible stream habitat to only 3,300 miles. With many Great Lakes fish species using tributaries as spawning and nursery habitats, these barriers are a significant factor impairing the full recovery of fish populations in the Great Lakes. Similar fragmentation occurs on other inland waters with [...]
