NMU grad student researches diet of Lake Michigan fish

NMU grad student researches diet of Lake Michigan fish

One of the top predators on the food chain in Lake Michigan may be on its way out.

Burbot populations are being threatened or eliminated in some areas. It’s a fish that looks similar to a cross between a catfish and an eel.

The burbot is a native species of many Midwestern lakes, including the Great Lakes. Ishpeming native Casey Hares is a graduate student at NMU. He studied the burbot in Lake Michigan from Manistique to the state’s southwest corner.

“I think the most interesting aspect of my study, really, was to show the decreasing abundance of burbot in eastern Lake Michigan,” Hares said. “This is consistent with other Great Lakes; (it’s) happening in Superior and Lake Michigan proper.”

Hares studied the diet of the burbot by analyzing stomach contents from hundreds of fish caught from 1999 through 2012. He says their food sources changed significantly during that time.

“I think one of the interesting things is noticing how burbot have switched their feeding strategy as a result of non–native introductions of brown gobies,” he said. “Brown gobies have now become a very important component of burbot diet.”

Alewives are also a non-native species, like the brown goby. At first, alewives formed the majority of the diet of the fish that Hares studied, but their share of the diet declined rapidly as the study continued over the years.