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Sea Lamprey nest survey Connecticut River Glastonbury_edited.jpg

Migratory Fish

Migratory fish are essential to healthy river ecosystems. The Connecticut River hosts 8 species of migratory fish that travel thousands of ocean miles and over 200 miles upriver annually. These include alewives, American eels, Atlantic salmon, American striped bass, blueback herring, sea lampreys, and shortnose sturgeon. CRC's migratory fish restoration efforts include advocating for and expanding fish passage and raising awareness to our work through community science and education. 

Juvenile eel held in a hand.

Migratory Fish Data

Research and education about migratory fish in the Connecticut River help scientists and the public understand how to best support thriving biodiversity. That’s why we work with conservation partners to bring you a dedicated website full of resources. 

Group of volunteers, adults and kids, at a Sea Lamprey rescue on the Connecticut River. Standing in front of drained power station canal.

Community Science Events

Counting fish and nests, and rescuing some species from drained canals, requires dedicated volunteers! We offer dozens of engaging community science events annually, which typically run from April to July.  

Small bridge over Beaver Brook in Vermont.

Dam Removal

Dams are the most significant obstacle to fish passage in the Connecticut River, which is why we collaborate with partners and landowners throughout the watershed to safely remove old dams and restore healthy habitats. 

Angler on the river at sunset.

Angler Surveys

Angler surveys empower individuals to contribute valuable fishing data, informing researchers and becoming stewards of the rivers through their recreation. Thanks to these surveys, CRC connects the fishing community to conservationists, for a common goal of restoring migratory fish to the Connecticut River.

Thanks to Our Partners

Vermont Fish & Wildlife logo
U.S. Fish & Wildlife Service logo
NOAA logo
USGS logo
Alewives swimming.jpg

Migratory fish travel between freshwater and saltwater throughout their lifecycle to reach the habitat that best suits their needs for spawning, feeding, and finding shelter.  

The Problem: Dams and industrial practices have blocked spawning habitat and decimated migratory fish populations. Flows at main stem hydro-electric dams and canals, industrial pollution, and heated plant discharges into the river make this situation worse. Determined action is needed if the Connecticut River’s fish runs are to survive. 

The Solution: Require safe and effective fish passage at dams. Remove any deadbeat dams that no longer serve a purpose. Improve passage in tributaries to increase available spawning habitat. Discontinue any recent industrial practices that may be injuring migratory fish runs. Perform adequate research before making changes to main stem discharges and flow regimes to prove they will do no harm.  

All fish are mobile, but none on the Connecticut River make longer journeys than the suite of migratory fish moving upriver from the Atlantic Ocean:

blueback herring, alewives, stripped bass, American shad, American eels, Atlantic salmon, shortnose sturgeon, and sea lampreys. These migrations have been taking place for thousands of years. The journeys of these species may take them through thousands of ocean miles annually, and nearly 200 miles upriver. 

Anadramous Fish

Shad, lamprey, salmon, striped bass, blueback herring and alewives are anadromous fish. They are born in freshwater, swim to the sea to feed and mature, then return to the rivers of their birth to spawn.


Though some members of each species die after spawning, only the sea lamprey spawns as the final act in their long-life cycle. All other species may survive, return to the ocean, and then return to the river to spawn again. 

Two hands holding a juvenile sea lamprey.
American Eel on a riverbank.

Catadromous Fish

American eels are different. They are a catadromous species; born in the ocean, they travel to rivers and estuaries to feed and grow. After years of feeding and maturing in the Connecticut River watershed, American eels head back to the Sargasso Sea, a weed-covered expanse in the Caribbean, where they were born, to spawn along that sprawling sargassum algae mat near their counterparts, European eels.


This seaweed expanse has also been found to be the protective ocean habitat that young loggerhead sea turtles journey to after hatching on sandy shores and skittering into the sea.

Main stem and tributary dams are among the major, human-induced contributors to declining migratory fish populations on the Connecticut River. Fish passage facilities are in place at most main stem dams. However, changes in operations and discharges at main stem structures, and failing fish passage facilities, further impact surviving fish runs. In addition, thousands of poorly designed road crossings over streams block fish from reaching their available habitat. Culverts at these locations need to be replaced with fish-friendly structures. 

Critical fish passage and dam-removal work is also taking place on many tributaries and is in the works for others. We have successfully helped create fish passage, restore habitat and remove unneeded dams at dozens of watershed sites. In doing so, we’ve opened 424 miles of migratory fish habitat since 2014.  

The once prolific runs of American shad, blueback herring, alewives, and Atlantic salmon have been dramatically reduced over the centuries. Today, runs are a small fraction of their historic numbers. These species play an important role in a healthy river and marine ecosystem. 

Explore the New Migratory Fish Website! was developed by CRC and partners to share information about fish migration in the Connecticut River. You can browse the embedded website below, or open the website in a new browser window.

Sea Lamprey Nest Surveys & Rescues

Sea Lamprey nest survey in Glastonbury - Connecticut River
Sea Lamprey Rescue Connecticut River
Sea Lamprey Rescue Connecticut River
Sea Lamprey Rescue Connecticut River
Sea Lamprey Rescue Connecticut River
Sea Lamprey Rescue Connecticut River
Aliki Fornier profile photo, Connecticut River Conservancy.

Meet Aliki

Aliki is CRC's Ecology Planner. She has dedicated her career to conservation and restoration. Starting as a volunteer, she's been involved in monitoring cetaceans in the Indian Ocean, managing invasive species in Florida's brackish waters, and surveying New England brooks for endangered freshwater mussels.  Now at CRC since 2018, she collaborates closely with fisheries experts from state and federal agencies to engage and educate the public about conserving migratory fish in the watershed. Aliki's favorite projects involve hands-on fieldwork, like walking tributary rivers to locate sea lamprey nests. She involves volunteers in her conservation efforts, fostering community and environmental stewardship. In her free time, Aliki enjoys swimming and paddling with her dog, Kali, on the Connecticut River.

For questions about migratory fish or community science volunteering, contact us at volunteer - at - or call 413.772.2020 x207. 

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