TROY aquatic biologists search for freshwater mussels in local rivers

The researchers found multiple species of freshwater mussels in the lower Tallapoosa River.

The researchers found multiple species of freshwater mussels in the lower Tallapoosa River.

Researchers in Troy University’s Department of Biological and Environmental Science recently wrapped up exploring areas of the lower Tallapoosa River in search of three endangered freshwater mussel species in connection with a $54,769 grant from the State of Alabama Department of Conservation and Natural Resources. 

The areas searched stretched from the Thurlow Dam in Tallassee, Ala., to Fort Toulouse in Wetumpka, Ala., the confluence of the Coosa River. Dr. Brian Helms, associate professor and the Principal Investigator for the grant, said that stretch of river historically contained a few now federally-listed freshwater mussels.

“These species hadn’t been detected there in a long time, so we were going back just to verify if they were there or not. That stretch of the river is heavily regulated,” he said. “Thurlow Dam is a major hydroelectric dam from Alabama Power that releases water. Normally it’s a daily cycle where the water will raise four, six or eight feet or more, so it has a really dramatic impact on wildlife and makes it really hard for anything to live there.”

To search for the three specific mussel species—Pleurobema perovatum, Pleurobema decisum and Hamiota altilis—the pair had to overcome several obstacles posed by the river itself: inaccessibility and rapidly changing water conditions.

“A big part of this study that was actually interesting was we had to do a fair amount of reaching out to the community because most of the accessible points were on privately owned land,” said Jonathan Miller, a lecturer and aquatic biologist. “We had to find boat ramps that actually gave us access. There’s a kind of rocky outcrop surrounding most of the shores and you don’t want to take a boat flying down in that.”

Jonathan Miller shows the corrugations on a freshwater mussel.
Jonathan Miller shows the ridges on a freshwater mussel.

Despite having success last year in finding the second-largest known population of a highly endangered mussel in the Pea River, they were unable to identify the federally-listed species. However, Miller said they were able to find multiple species of native freshwater mussels.

“That was pretty awesome, considering there’s not been thought to be very many mussels in general in this lower reach of the Tallapoosa,” he said.

“We found some surprisingly dense mussel beds, which I was not expecting either,” Helms added. “It was really exciting to see some of those in this stretch of the river.”

Although they’re no longer under contract with the grant, Miller and Helms agree there’s more work to be done. And because of the small size of the mussel research community, there’s always new things to look for and information to share.

“Jonathan and I both have a wish list, which I think is pretty parallel. There’s a couple of other places we’d like to hit, particularly some of the tributaries,” Helms said. “Our mussel research communities are rather small across the southeast, generally, so we tend to know each other and you get wind of who is going to be where and who needs specimen samples from this place. The biologist in us and the love of nature and the species urges us to try to contribute more.”

This is where Dr. Kaelyn Fogelman, assistant professor, comes in. She specializes in thermal intolerance, hypoxia tolerance and the feeding/energetic needs of crayfish and mussels, and her research hopes to explain why one species is dominating a community or why there is a lack of reproduction in a species.

“When we make observations on the status of these species in the wild, I am able to investigate the mechanisms behind them through researching environmental tolerances and life history traits,” she said. “We can then compare what the conditions are in the systems we find, or hope to find, them in and see if that explains their decline. Once we understand their basic needs, we can also move forward with making recommendations to our colleagues that make management and conservation decisions so that they can work on ensuring these ecosystems are within optimal ranges for species that we are trying to protect.”