• The Huron River has more than 30 native mussels, a dozen of which are on the state’s threatened and endangered species list
• Plans to remove Peninsular Paper Dam in Ypsilanti could disrupt the Huron River’s mussels
• Volunteers helped relocate 3,000 mussels ahead of the dam’s removal

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This summer, groups of about a dozen people each ventured into the Huron River in Ypsilanti just downstream of Peninsular Paper Dam, donning snorkeling gear. 

In sections of the river that ranged from a few inches deepto a few feet, they plunged their faces into the water and started digging around. They were looking for mussels. 

“We got into a rhythm at some point where somebody would find a mussel, they’d hold it up, and we’d all yell,” said William Moore, a summer aquatic field intern with the Huron River Watershed Council, involved in the mussel search.

Volunteers like Moore, in conjunction with engineers and other experts, relocated 3,000 mussels this summer to protect them from harmful fine sediment that could result from the planned removal of the dam. 

Mussels are found in lakes and rivers all across Michigan, many living for 20 to 30 years, but they are in decline. In the early 1900s, their shells were used to make mother of pearl buttons and they were heavily harvested. Modern threats like pollution and changing water depths are difficult for mussels to evade because the shelled creatures aren’t very mobile.

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The Huron River has more than 30 kinds of native mussels but there, too, many are disappearing. Four once found in the river are consideredendangered by the federal government. The state also tracks threatened and endangered species and a dozen mussels found in the Huron River are on that list. 

All mussels in Michigan are protected by the state, regardless of how rare or common they are. Mussels in the state cannot be touched or moved without a proper permit. 

Peninsular Paper Dam was first built in 1867, decommissioned in the 1970s and acquired by Ypsilanti in 1986. The dam is slated to be removed as early as next year since it is not in use and its aging infrastructure has been identified as a hazard. While dam removal is generally seen as helpful for aquatic life because it increases water flow, reconnects the river, reduces sediment and improves water quality, in this case, there was concern that the dam’s initial removal could impact the rare mussels. 

“When a dam is taken out, the fine sediment behind the dam is all kind of churned up and entrained into the water and brought downstream,” said Paul Steen, director of science for the Huron River Watershed Council. 

That can be a problem for mussels, Steen said, because “they can’t really move. They can move a little, but they’re not like fish. If a mussel gets into a bad situation, it can’t save itself. It’s gonna die.”

A survey conducted a little ways upstream and downstream of Peninsular Paper Dam in 2024 found more than a thousand live mussels. Eight species were recorded, three of which were on the state’s threatened list: purple wartyback, wavy-rayed lampmussel and the black sandshell. 

To keep downstream mussels intact, the Michigan Department of Natural Resources instructed Ypsilanti to relocate native mussels found immediately below the dam before the structure is removed. Ypsilanti contracted the engineering firm GEI to plan and coordinate the effort. The Huron River Watershed Council, along with other experts, partnered as volunteers.

When engineers assessed the Peninsular Paper Dam, they found less sediment had built up behind the dam than they initially feared, Steen said, but they still expected sediment to accumulate along the edges of the river, where flow tends to be slower. So the DNR said the mussels found on the edges of the river should be moved into the center. 

That is where the snorkeling gear came in, which Steen said was a great opportunity to get volunteers involved.

“They get a chance to put on the mask and snorkel and search along these lines to locate these mussels,” he said. “It’s this unique experience of being fully immersed in the river, the outside world just gets shut away, the sound of airplanes and cars kind of disappears, and it’s just you in the river.”

Moore, the intern with the watershed council, said searching for the mussels was like hunting for treasure and, every time he found one, it felt “awesome.”

“People don’t realize that activities to preserve native and endangered species like this can be fun. I was out there having the time of my life,” he said.

After the dam is gone, Steen said, they hope to look at how quickly the mussels can repopulate areas above the dam that used to be still water.

“We’ll start seeing baby mussels upstream where there used to not be any, as a result of the dam removal,” he said.

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