Rivers, streams, and lakes around the Great Lakes are full of mussels filtering our water to make it clean. But researchers say native mussel populations are in decline, largely driven by invasive zebra mussels.
New research out of Central Michigan University aims to reverse this trend.
In a lab on the campus of Central Michigan University, the air is brimming with the sound of flowing water and electric pumps.
Rows of tanks are full of large fish and, on further inspection, mussels.
Dr. Daelyn Woolnough is an expert on Great Lakes mussels working in CMU's biology department and with the Institute for Great Lakes Research. She explained that during a mussels larval stage it has to attach to fish.
“These are largemouth bass, and they are our hosts for our native freshwater mussels. Like a tiny little Pac man, it attaches to the gills of a fish and it has to have a particular fish species in order to grow into an adult.”
Woolnough said this life cycle makes mussels incredibly vulnerable to changes in the environment - and that’s a problem because mussels play an essential role in the health of the ecosystem.
“We know that one mussel, one clam, can filter up to sixty gallons a day of water. So we are talking about a large filtering capacity because sometimes in our rivers you can find up to fifteen per meter squared or yard squared.”
Native freshwater mussels, however, are facing threats - from invasive zebra and quagga mussels. According to Woolnough roughly 75 percent of the native mussel species in the Great Lakes region are listed as endangered, threatened, or special concern. She said their decline is largely being driven by invasive zebra mussels.
Woolnough said that’s a problem because zebra mussels aren’t as good at filtering contaminants like e coli from the water as some native mussels.
“They take them out of the water and hold them in their bodies, and they can live for like 75 years old. The zebra mussels can’t do that because they are two or three years old, they will die, and then they will release those contaminants back into the water actually causing more water quality problems.”
Woolnough said it’s possible that native mussels are masking just how polluted Great Lakes waterways have become.
If native mussels go away Woolnough said it could have a cascade effect: lowering water quality and affecting other river organisms, like fish.
To solve this problem Woolnough and a team of researchers are pairing with the Michigan DNR to grow new native mussels in a hatchery and then introduce them into the Kalamazoo River.
Scott Hanshue is a biologist with the DNR. He said it’s important to bolster clam species and increase river diversity.
“This is groundbreaking work for the state of Michigan. We have not done mussel propagation at this level as yet.”
Hanshue said similar work has been done in Ohio and Wisconsin.
“Other states are well ahead of us in terms of mussel propagation as well as the federal government and some of the natural fish and wildlife hatcheries.”
The research is supported by a three year, 499 thousand dollar grant from the Kalamazoo River Community Recreational Foundation.
Woolnough said while the research will be focused on the Kalamazoo River, her findings will have implications for the region.
“We should be able to use that information to help with the water quality across the state and therefore across the Great Lakes.”
If the project is successful Woolnough and Hanshue say the state will begin using this method across Michigan to stabilize mussel populations and keep waterways clean.