Public Reminder: Do Not Disturb Spawning Sea Lamprey in Connecticut River Drainage

Sea lamprey are native to the Connecticut River, and their spawns are beneficial to the aquatic ecosystem.

by Vermont Fish and Wildlife

The Vermont Fish and Wildlife Department is reminding anglers and the public to avoid disturbing spawning sea lamprey that may currently be found in the Connecticut River and several of its tributaries. “Sea lamprey are native to the Connecticut River basin and play a vital role in the ecosystem,” said Lael Will, fisheries biologist with Vermont Fish and Wildlife.

Vermont is also home to a separate population of sea lamprey that are actively controlled as a nuisance species in Lake Champlain. Confusion can arise over the differing management goals for these two populations of Vermont sea lamprey.  We believe it is important to highlight and contrast the conservation value of Connecticut River sea lamprey, educate the public and encourage folks to do their part to protect this important population of fish.”

“If you happen to see a spawning sea lamprey or a lamprey carcass, don’t be alarmed,” said Will.  “The fish provide a number of important ecological benefits and are considered a Species of Greatest Conservation Need in both Vermont and New Hampshire.”

Each year sea lamprey spawn during the spring in the main stem of the Connecticut River as far upstream as Wilder Dam as well as in many of its tributaries, including the West, Williams, Black, and White Rivers.

Upon returning to freshwater to spawn, adult sea lamprey are non-parasitic and die shortly after spawning, and their carcasses play a critical role in cycling important marine nutrients into freshwater ecosystems.

In the Connecticut River, larval lamprey live in freshwater the first few years of their lives, remaining sedentary and burrowed in sandy substrate while filtering detritus from the water for nutrition.  At around five years of age, they transform into juveniles and emigrate to the ocean where they attach to and feed on fish as parasites.  In turn, lampreys are a food source in the estuarine and marine environment for a number of fish, marine mammals and birds.

While existing for over 350 million years in the Atlantic, anadromous sea lamprey have co-evolved with their oceanic hosts and their populations are considered to be in balance.

The species is currently managed under the Connecticut River Atlantic Salmon Commission, which includes four state agencies, two federal agencies and representatives of the public.  Among other efforts, Vermont Fish and Wildlife has been working to improve fish passage facilities within the Connecticut River drainage to enable native sea lamprey to successfully complete their migrations to spawning habitat.

“In 2021, more than 20,000 sea lamprey passed the Holyoke Dam in Massachusetts, and our goal is to continue to improve fish passage and flows on the river to not only help lamprey spawning, but to also support all migrating fish species,” Will said.

To learn more about Vermont Fish and Wildlife’s various fisheries management programs, visit www.vtfishandwildlife.com.

6 on “Public Reminder: Do Not Disturb Spawning Sea Lamprey in Connecticut River Drainage”

  1. LOU

    YOU DONT MENTION ALL THE SALMON THAT THEY HAVE KILLED THAT WE HAVE BEEN TRYING TO BRING BACK FOR AT LEAST 40 YRS . NOT COUNTING THE STRIPERS IVE CAUGHT WITH THE LAMPREY HANGING ON THEM. I LIVE ON THE RIVER IN SPRINGFIELD , MASS .

    1. MSL

      Science says you are incorrect. Lamprey do not kill their host in saltwater environments. They are native and the value of the nutrients their carcasses provide is significant. Alaskan rivers are super fish producers because of the nutrients they dead salmon leave behind. Lampreys are the only anadromous fish in New England rivers that die upon completion of spawning . They fertilize our rivers that naturally lack nutrients, in part due to the geologic make-up of our rivers. I fish daily and have never observed an ocean fish with a Lamprey attached to it, nor found a dead fish with Lamprey scars. Have you?

    2. Nick

      In the Connecticut River and other waterbodies in the Eastern/Atlantic Watershed sea lampreys are very beneficial to salmon restoration. Their larvae/ammocete filter feed making the water cleaner for salmon. Lamprey move gravel for their spawning beds preparing them for salmon. Their corpses provide marine nutrients the Connecticut has lacked for centuries. My father remembers catching and eating them in tributaries to the Baltic Sea as a kid. Many native tribes in the Pacific Northwest consider lamprey an important part of their diet. In the English county of Gloucestershire lamprey pie is a tradition. Interestingly, the Great Lakes have a native population of lamprey that do not parasitize fish and filter feed all their lifetimes. Lake Ontario and Lake Champlain are not isolated from the Atlantic Ocean by the Niagara Falls and the sea lamprey population there is native. Before the Salmon and Lake Trout strains endemic to them were extirpated, sea lampreys fed on them nonlethaly. The salmonids currently there are of strains from Lake Sebago and are not adapted to life with lampreys. When in marine ecosystems sea lampreys are almost never lethal to their hosts especially their preferred hosts tuna and large sharks. To large oceanic fish they are as harmful as mosquitoes or leeches to humans.

  2. Petromyzoniformes

    Thank you for this article. As it states the lamprey are native to the CT River and some tributaries. The lampreys certainly didn’t wipe out the Atlantic Salmon, dams and destruction of habitat did that. And as far as stripers go, lampreys are nothing compared to the commercial catch and sale of the large stripers.

  3. Dave K.

    MSL, Just look at how nature designed that mouth. Lamprey’s are a parasite. I pulled three off the side of shad this spring. They chew right into them.

  4. Nick

    In the Connecticut River and other waterbodies in the Eastern/Atlantic Watershed sea lampreys are very beneficial to salmon restoration. Their larvae/ammocete filter feed making the water cleaner for salmon. Lamprey move gravel for their spawning beds preparing them for salmon. Their corpses provide marine nutrients the Connecticut has lacked for centuries. My father remembers catching and eating them in tributaries to the Baltic Sea as a kid. Many native tribes in the Pacific Northwest consider lamprey an important part of their diet. In the English county of Gloucestershire lamprey pie is a tradition. Interestingly, the Great Lakes have a native population of lamprey that do not parasitize fish and filter feed all their lifetimes. Lake Ontario and Lake Champlain are not isolated from the Atlantic Ocean by the Niagara Falls and the sea lamprey population there is native. Before the Salmon and Lake Trout strains endemic to them were extirpated, sea lampreys fed on them nonlethaly. The salmonids currently there are of strains from Lake Sebago and are not adapted to life with lampreys. When in marine ecosystems sea lampreys are almost never lethal to their hosts especially their preferred hosts tuna and large sharks. To large oceanic fish they are as harmful as mosquitoes or leeches to humans.

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