Mussels The Conservancy’s Katie Kennedy shows off the eastern elliptio, a native freshwater mussel. © Ryan Kennedy

Stories in Connecticut

Getting Answers from Aquatic Animals

Lamprey and freshwater mussels give us clues about river health.

Aquatic species can tell us a lot about the quality of their habitats. Fish and mussels depend on clean, flowing water to thrive, which is why Conservancy scientists are looking to them for clues about how to restore river health.

Since the Norton Mill Dam was removed by the Conservancy in early 2017, the Jeremy River has been a great place to study. Sally Harold, director of river restoration and fish passage for the Conservancy in Connecticut, led a team of interns on the river to survey for sea lamprey nests.

Sea lamprey are a native migratory species in Connecticut and an important part of a healthy stream ecosystem. By counting nests, Conservancy scientists are able to estimate populations in a stream.

“The dam blocked migratory species except a few sea lamprey that made it through the failed mill race a few years ago,” says Harold, “but now that the dam is gone, we are seeing an increase in nests, confirming improved passage.”

Freshwater mussels are another important indicator of river health; unfortunately, many mussel species are in decline. Katie Kennedy, river scientist for the Conservancy’s Connecticut River program, spent the summer collecting habitat data along the Connecticut River in places with and without mussels to help us understand the conditions that mussels need to thrive.

“Soon,” she says, “this information will help us work more effectively to both revive these species and restore river ecosystem health.”