By Piotr Parasiewicz and Kathleen Ryan Gazette Contributing Writers
Although it may appear modest at first glance, the Fort River, which rises in Amherst and makes its way through Hadley to the Connecticut River, boasts distinction among the 53 tributaries of the Connecticut. It is the longest free-flowing tributary of the big river in Massachusetts, and it is home to an impressive array of rare and intriguing species. From the sea lamprey to a wide variety of mussels, the Fort is a treasure trove of biodiversity right in our own neighborhood.
Sometimes called living fossils, sea lampreys have been spawning in rivers for 360 million years. Every June the lampreys migrate up the Fort River from Long Island Sound, build nests and deposit eggs in the stream bed. Their larvae live as filter feeders in the river’s mud for three to seven years. Following metamorphosis into adults, the sea lampreys return to the Atlantic, where they live as parasites on other fish. In about three more years, when they become sexually mature, the lampreys migrate back to their birthing grounds for spawning, after which they die. The carcasses then become an important source of food for other aquatic organisms. Their eggs also offer a feast to numerous fish, which also use the lampreys’ nesting mounds as convenient spawning sites.
The American eel is another migratory fish of the Fort River, following a pattern that is opposite to that of the sea lamprey. The eels first spawn in the mid-Atlantic before spending most of their lives in rivers like the Fort. The eel serves as a host species for another important member of the aquatic community, the freshwater mussel known as the eastern elliptio. Mussels have limited mobility, but their larvae use aquatic vertebrates for dispersal, attaching themselves to fins or gills of the eels and parasitizing them until dropping off in a different location.
Mussels play a vital role in rivers and are sentinel indicators of ecosystem health. One adult mussel can filter up to five or more gallons of water per day, contributing greatly to the water quality of the river.
Excrement from these sedentary organisms enriches organic matter, while their shells contribute to stabilization of riverbed. The long lifespan (100-plus years) of mussels also offers a good perspective on the history of the environmental health of a river by acting as a time capsule for future research.
The eastern pearlshell, another mussel species found in the Fort River, parasitizes only salmon and trout. Substantial quantities of these mussels found in the river indicate a healthy cold-water environment suitable for these fish.
The Fort River, with nine of the 12 mussel species found in New England, is one of the three most diverse rivers in Massachusetts. Other nearby streams can’t support such a high number of mussel and other aquatic species due to a variety of human impacts, including landscape alteration, deforestation, contaminant runoff and dams.
Dams are a key problem for aquatic species in New England streams and rivers. The region’s long history of settlement and water-powered industry has left thousands of forgotten and unused dams in place. Dams alter rivers and species richness by impeding sediment and nutrient flow in rivers, blocking migratory movement of fish and forming ponds from once-naturally flowing rivers. Ponds are warmer than streams because their greater surface area absorbs more solar radiation; the higher temperatures make the habitat unsuitable for cold-water fish. As a result, fish species typical of a pond are abundant behind dam impoundments, displacing river species in the process.
The Fort River, however, is an exception to this trend: it is a free-flowing stream from its beginning to the Connecticut. Local scientists studying fish and other animals document healthy and diverse populations of resident and migrating species. The Fort also provides recreation, scenic beauty and drinking water for Amherst and Hadley residents. Yet without active preservation and management, the Fort River is not guaranteed a secure future. Fortunately, there’s reason for optimism.
The Fort River Stewardship Project, a collaboration between the Hitchcock Center for the Environment and the Rushing Rivers Institute, both in Amherst, aims to maintain the health of this often overlooked waterway through research on aquatic species and habitat condition, water quality monitoring and educational programs to muster community support. Data collected through continued research will also be available to resource managers, scientists, students, area environmental advocacy organizations and the community.
This project will pave the way for developing long-term management strategies for this wonderful local resource.
Piotr Parasiewicz, Ph.D. is founder and director of the Rushing Rivers Institute. Kathleen Ryan is outreach coordinator at Rushing Rivers.
Earth Matters, written by staff and associates of the Hitchcock Center for the Environment at 525 South Pleasant St., Amherst, appears every other week. For more information, call 413-256-6006, or write to us.Click here to return to full list of Earth Matters articles.