HADLEY — A three-day excursion on the Connecticut River this week aimed to improve scientists’ understanding of what they say is often an understudied species, but one that is crucial to improving water quality in the river.
The U.S. Fish and Wildlife Service, U.S. Geological Survey, state Division of Fisheries and Wildlife, and students from the University of Massachusetts Amherst have been surveying the bottom of the Connecticut River to research freshwater mussels. Staff from across the East Coast have spent the last three days on the river above the Holyoke Dam, collecting mussels in various locations to help better understand these living freshwater filters, including those in Massachusetts that are listed as endangered.
Hershberger, a doctoral student in UMass Amherst’s Organismic and Evolutionary Biology Program, compares the mussels to coffee filters for their ability to clean the water.
“Some people argue [mussels] are not that charismatic, but I think they 100% are!”
Alexa Hershberger
“Some of their ecosystem services, I would describe them like the coffee filters of the river,” she explained. “There is some research where [mussels] change the hydrology of the system, too, and they also provide habitats for other aquatic insects.”
“You have tons of fish biologists doing fish surveys all over the place, but not a lot of knowledge when it comes to mussels,” U.S. Fish and Wildlife Facilities Operations Specialist Tim Warren said on Thursday while traveling down the river from Hadley to the top of the Holyoke Dam. “This is going to help us estimate the population of mussels and species abundance in this stretch that we’re serving.”
To do this data collection, Warren and MassWildlife Natural Heritage and Endangered Species Program Aquatic Ecologist Jason Carmignani explained the USGS provides the team with search locations that vary in water depth, and are randomized along “transects,” which are used in ecological surveys to collect data and avoid bias in picking a survey spot.
Using locations that were previously mapped by the USGS, the team on the boat with USGS divers Collette Johnson and Michael Schramm geared up and dove in to collect up to 6 inches of material at the bottom of the river, which is then brought to the surface in a mesh bag. The contents are spilled out and sifted through for mussels. In their first dive, they collected eastern elliptio mussels and some rocks on a sandy riverbed.
Warren said the team has been collecting a variety of mussels that are measured for length and to get an age estimate, which is done by examining the rings that circle the shell. The Massachusetts endangered species, like the yellow lampmussel, were also examined to determine their sex and swabbed for DNA that can help understand reproduction levels. That information will be passed along to the USGS, which is taking the data and analyzing it for federal and state partners.
After each examination, the mussels were returned to the bottom of the Connecticut River with one of the scuba divers. As of Thursday afternoon, around 15 yellow lampmussels had been found and examined by the teams.
“We put that [data] into our records, and we actually use that for its own purposes, for monitoring populations, but we’ll also use those points to regulate,” Carmignani explained, saying the data can help inform their authority to enforce the state Endangered Species Act when development near, or in the river, is proposed.
The data collected over these three days is valid for the next 25 years, Carmignani explained, but the hope is that MassWildlife and other agencies will have further opportunities to update the data as needed.
This future opportunity, Warren said, may be in a survey later this year, or in 2026 in Turners Falls near the Silvio O. Conte Anadromous Fish Laboratory, especially if water flows change below the Turners Falls Dam.
Although the goal is to get to Turners Falls and farther up the Connecticut River in the future, funding and planning for surveys can cause some delay, Warren said. However, federal funding via the USGS for this survey remained unimpacted by federal cuts.
When asked about the value of researching the mussels, Hershberger said in her eyes, everything in a river is connected, and it is important to understand the components to preserve species and advocate for the mussels.
“Everything’s touching the water, everything’s processing it, so being able to support and understand this component, especially something that’s so low in the food chain and ecosystem, it just connects everything all together,” she said. “It’s a sense of ownership, too, so even if it’s a small system that I’m helping, it’s still helping conserve it longer.”
