Project Description
The Merrimack River is the fourth largest river system in New England. In 2016, the river herring (alewife and blueback herring) spawning run consisted of over 400,000 fish, representing the largest run in a time series spanning over 30 years since data has been collected at fishways in Lowell and Lawrence, MA. These increases were likely due to stocking efforts and other natural fluctuations in the population. The Concord River is a 16.3-mile tributary of the Merrimack River that flows into the Merrimack at Lowell. Anadromous fish, such as alewives, American shad, and blueback herring, historically migrated through the streams and rivers of the Sudbury-Assabet-Concord (SuAsCo) River Watershed to reach their spawning grounds until the construction of dams and weirs blocked their upstream movements.
To compensate for injuries to diadromous fish in the SuAsCo River Watershed, $20,100 in funding was provided by the Nyanza Chemical Waste Dump and Charles George Reclamation Trust Landfill Trustee Councils to monitor the movements and behaviors of alewives and evaluate fish passage on the Concord River. In 2017 and 2018, biologists from the U.S. Fish and Wildlife Service's (USFWS) Central New England Fish and Wildlife Conservation Office and the Massachusetts Division of Marine Fisheries (Mass DMF) surgically inserted acoustic transmitters into 180 alewives captured at the Essex Dam on the Merrimack River. The tagged fish, along with 200 to 500 others that were not tagged, were transported by truck and released at three upstream locations: at the upstream exit of the Centennial Falls Fish ladder, in the impoundment above the Talbot Mills Dam on the Concord River, and in the Sudbury River. Approximately 25 receivers were deployed throughout the watershed to detect the fish as they swam by. The tagging study found that mortality rates for the fish attempting to make their way downstream over the dams was more than 50%. Overall survival was low as only 10 to 15% of the tagged fish were detected exiting the river. The study also found that fewer fish entered the Assabet River than the Sudbury River, indicating that the Sudbury contains more preferred spawning habitat for alewives than the Assabet. The valuable information about alewife behavior and survival gained from this acoustic telemetry survey will better inform future restoration efforts for anadromous species in the SuAsCo River Watershed.
Restoration Land Ownership
County or Municipal; Private
Parties Implementing Restoration
Massachusetts Division of Marine Fisheries
DOI Project Representatives
Fish and Wildlife Service