Manistique dam to become sea lamprey barrier

Manistique will soon have a new barrier dam. The Manistique Papers, Inc. Dam, built in the early 1900s to power a hydroelectric plant, is deteriorating.

"It was just dug down to bedrock, so none of the cracks and fissures were sealed," Manistique Wastewater Superintendent Corey Barr said. "At that time, it didn't need to be. It was just the conveyance of water through an old power plant."

Though the dam hasn't produced power in decades, those cracks are a problem. They're letting sea lampreys migrate from the Manistique River to Lake Michigan.

"Sea lampreys are not strong swimmers, but they're amazingly adept at finding holes and cracks so that they can move upstream to suitable habitat," said Jessica Barber, Supervisory Fish Biologist at the U.S. Fish and Wildlife Service.

Sea lampreys are an invasive, parasitic species present in all five Great Lakes. Each lamprey eats up to 40 pounds of fish a year. In the Manistique River alone, they eat 1.6 million pounds of fish each year.

The new dam's main purpose will be to prevent lampreys from getting to Lake Michigan.

"Eliminating or trying to eliminate the lamprey eel is also going to be a benefit to the fish," Barr said.

It will also eventually help walleye and salmon travel upstream.

"It would look pretty similar, without the gates on top," Barber said. "It would be a fixed crest structure, the same elevation all the way across, with a few stoplog sections to facilitate sea lamprey trapping and potential fish passage in the future."

The U.S. Fish and Wildlife Service has spent nearly $8 million on lampricide treatments since 2003. The new dam, which should help cut future costs associated with lamprey population control, is estimated to cost between $3 million and $5 million. Engineers plan to start construction in 2018.