Great Lakes' Largest Fish Receiving New Habitat

by Kevin Walter

Photo of a juvenile lake sturgeon

Did you know the Great Lakes are home to a giant species of fish that has been around since the time of the dinosaurs? Lake sturgeon can live up to 100 years and grow to over eight feet long, but these freshwater giants haven’t proven immune to the effects of human activity in more recent times. Habitat degradation and over-harvesting in the late 19th and much of the 20th centuries led to lake sturgeon being listed as a threatened species in 1976.

But partner agencies from around the Great Lakes region, including Michigan Sea Grant, U.S. Fish and Wildlife Service, and the National Oceanic and Atmospheric Administration, are hoping to change that. They teamed up over the summer of 2012 to restore about an acre of habitat in Michigan’s St. Clair River by constructing rocky reefs to enhance fish reproduction and rebuild native fish populations. A total of nine reefs, each approximately 120 feet long, 40 feet wide and about 2 feet high, were made of loosely piled limestone and fieldstone rocks.

Surprisingly, even before construction was complete, researchers observed sturgeon swimming around the reefs and found eggs in the structure. Jennifer Read, project lead from Michigan Sea Grant, said, “We were very excited to see sturgeon using the reefs even while they were under construction, which is good evidence that the reefs will contribute to enhanced populations over time.”

Several additional species, including others that are endangered or threatened, may also eventually benefit from the project. “We’re also looking forward to verification that other native species use the site — lake whitefish, northern madtom, and possibly walleye — to confirm that these reefs will benefit multiple species in the St. Clair River,” said Read.