This article was originally published inYale Environment 360and here appears as part of ourair conditioning tablecooperation.
"There are thousands of sea lampreyswent upstream [on the Connecticut River] every year. This is the predator that ruined the Great Lakes trout fishery. [Lightfish] literally suck the life out of their host fish, specifically small fish like trout and salmon. Fish ladders should be used to reduce lamprey numbers.” So he wroteAmor(Massachusetts)tribune eagleDecember 15, 2002.
If that's true, why this spring is Trout Unlimited - the nation's leading trout and salmon advocate - helping the city of Wilton,Connecticut, and an environmental group called "Save the [Long Island] Sound" in a project to restore 10 miles of sea lamprey spawning habitat in the Norwalk River?
Why this summer, the first large returnees of Pacific lampreys - a species similar to sea lampreys - will climb the specially designed lamprey ramps on the Columbia River dams and dive into historic spawning habitat atOregon,Washington, euIdaho?
And why, when the canal at Turners Falls on the Connecticut River collapses in September, will the Connecticut River Conservancy, Fort River Watershed Association and Biocitizen Environmental School be rescuing stranded sea lamprey larvae?
The answer is ecological awakening: the gradual realization that if all of nature is good, no part of it can be bad. In their natural habitat, sea lampreys are keystone species that support vast aquatic and terrestrial ecosystems. They provide food for insects, crustaceans, fish, turtles, martens, otters, vultures, herons, herons, ospreys, ospreys and hundreds of other predators and scavengers. The lamprey larvae, embedded in the bed of the stream, maintain the water quality by feeding through the filter, and releasing pheromones, attracting the adults that spawn from the sea. As the adults die after spawning, they supply barren springs with nutrients from the sea. When sea lampreys build their communal nests, they clear river bottom silt, providing spawning habitat for numerous native fish, especially trout and salmon.
Environmental consultant Stephen Gephard, former head of Connecticut's anadromous fish division, calls lampreys "environmental engineers" as important to native ecosystems as beavers.
Sea lampreys, over 340 million years old, spawn in fresh, cold, flowing water. These are fish without bones, jaws, like eels with fleshy fins. They extract body fluids from other fish using toothed suction discs. Both sea lampreys and Pacific lampreys are widely reviled because they are perceived as "ugly" and because sea lampreys decimated native fish in the upper Great Lakes when they gained access to these waters through man-made canals, likely the Welland Canal. that bypassed Niagara Falls. When they got there, they nearly eliminated the valuable commercial and sport fishing of lake trout (the largest species of cutthroat trout, not true trout such as rainbow, cutthroat, and brown).
In the 1960s, non-native sea lampreys reduced the annual commercial catch of lake trout in the upper Great Lakes from about 15 million pounds to half a million pounds. In 1955You haveeuUSAestablished the Great Lakes Fisheries Commission, which controls lampreys with barriers, traps and a highly selective larval poison called TFM. Lamprey control costs $15 to $20 million a year. Without it, the continued recovery of lake trout would be impossible and the populations of all other game fish would collapse.
But in salt water, lampreys are in natural balance and do not deplete anything. When they go up freshwater streams to spawn, they cannot “suck the life out of their host fish” because they go blind and lose their teeth.
The original habitat of sea lampreys extends from Labrador to the Gulf of Mexico and from Norway to the Mediterranean. The native habitat of Pacific lampreys extends from the Aleutians to Baja California and from Siberia to Japan.
Pacific lampreys are highly prized by Pacific Northwest tribes for food, ceremony, and medicine, and these tribes encourage recovery. The US Fish and Wildlife Service now recognizes the Pacific lamprey as a "high conservation risk" in most watersheds. The most recent international status assessment lists it as "critically endangered" in Oregon, Washington, and Idaho; Mexico classifies it as "threatened".
Sea lampreys are a traditional delicacy in Europe. In a fit of royal gluttony, King Henry I of England is said to have died of "lamprey gluttony". They are still hunted commercially in Spain, Portugal and France. There are recovery works, mainly in Portugal where the species is listed as “vulnerable”.
But in North America, lampreys are largely neglected as a food. And because of the Great Lakes disaster, gratitude for the Great Lakes is an ongoing process. In the early 2000s, the Maine Department of Fish and Wildlife captured and killed spawning sea lampreys. He also opposed the removal of a dam on the Sheepscot River (completed in 2019) because it would give lampreys access to historic spawning habitat.
When Fred Kircheis headed the Maine Atlantic Salmon Commission, he attributed the department's persecution of lampreys to "uninformed bias" and the fact that "transformers" (newly transformed larvae) left scars the width of a pencil on several landlocked salmon in Sheepscot Lake. Normally, he explains, transformers just hitch a ride just absorbing themselves into the fish. But when low tide temporarily blocks access to the sea, they occasionally feed. with minor damage to the hosts.
Today, the Department is fully involved in lamprey recovery. On Maine's Penobscot River, lamprey rapids are exploding now that the largest river restoration project in North America has removed two dams and bypassed a third, opening up an additional 2,000 miles of habitat. Maine researchers report that small fish are growing faster and larger around community lamprey nests and that brown trout and salmon are spawning in large expanses of silt-free gravel lampreys.
The global leader in sea lamprey recovery and education is Connecticut. Not only does it remove impassable dams and channels, it is the only state to restore the tracks of extinct sea lampreys by relocating pre-spawning larvae and adults. Sea lampreys do not return to their home rivers like salmon; therefore, when Connecticut moves lampreys to their former habitat, the entire Atlantic coast benefits.
“Connecticut was the first state to publicly challenge conventional wisdom about the sea lamprey and has taken every opportunity to educate the public and promote recovery,” says Gephard. "Not a single statement or misrepresentation has gone unchallenged. Opposition to the sea lamprey quickly faded in Connecticut, then other states bordering Connecticut, and finally most of New England.
Writing in May 2022estuary, Gephard and his colleague, fisheries consultant Sally Harold, reported what they observed while diving downstream from a common lamprey nest: “An entire school of spotted grebes remains, intimidated by our presence, and swallows any stray eggs that pass over the gravel mound. . Dozens of common eye-eyes, the males displaying vivid orange flashes on their flippers, dart in and out of the nest, snatching the tiny eggs before they sink to the bottom. Even when the egg lands on gravel, it may not be safe. As we watch, the heads of small American eels - elves - come out of the gravel in search of eggs. A typical female lamprey will produce around 200,000 eggs, so there's plenty to share."
On the main course of the Connecticut River, Gephard sees the carcasses of spawning lampreys boiling from feeding on walleye larvae, a staple food for birds and dozens of species of fish.
Sean Ledwin, director of Maine's Bureau of Sea Run Fish and Habitat, has worked with Pacific lampreys. To illustrate the difference between Western and Eastern perceptions, he tells the story of his outreach efforts. “In Maine,” he says, “people are horrified when we show them sea lampreys. We put a Pacific lamprey on display at an aquarium in California, and a Hoopa kid said, 'Looks delicious.'"
But outside the tribe, education remains a challenge. "The general perception is that lampreys are ugly, disgusting and dangerous," notes Christina Wang of the US Fish and Wildlife Service's Department of Fish and Wildlife Conservation. “Newspapers continue to run headlines like 'bloodsucking vampire fish.' Save them or kill them?” People, especially midwestern transplants, are terrified of lampreys. I have been a lamprey biologist for 20 years. When I started, the only people who cared about lampreys were the tribes. Now we are reaching more people. We have an exhibit at the Oregon Zoo. The person usually walks in and says, 'Oh, are you trying to get rid of them? Will they cling to our legs?” But then we tell them the facts and they change their minds.”
Unlike sea lampreys, Pacific lampreys can climb steep waterfalls, sniffing and resting as they go. But they have issues with the rough, sharp edges of traditional fish ladders. So the US Army Corps of Engineers, a partner in the multi-entity Pacific lamprey conservation initiative, designed nearly vertical aluminum lamprey chutes with rest pools that allow a large percentage of lampreys to cross the river dams. Colombia.
In the river, Pacific lampreys face swarms of non-native predators such as smallmouth bass, striped bass and walleyes, as well as an unnatural abundance of native predators created by pools and lampreys and other marine fish gathered near dams. These predators include sturgeon, sea lions, seals, gulls, terns, cormorants, and pike. The Pacific States Marine Fisheries Commission even pays a bounty for pike.
Predators, habitat destruction, global warming and past persecutions of lampreys – including managers using the fish poison rotenone – have reduced Pacific lampreys to such an extent that the only place tribes can legally capture them isWillamette Fallsno rio Willamette.
But the tribes are fighting back. The Nez Perce in Idaho, the Yakama in Washington, and the Umatilla in Oregon transfer pre-spawning adults, collected in traps at three dams on the lower Columbia River, to depleted habitat upstream. And the Yakama and Umatilla raise Pacific lampreys in hatcheries for breeding.
Pacific lampreys also differ from sea lampreys in that adults can spend a year or two in the river before spawning. This facilitates the transplant. Yaks transfer more but keep some to keep stock in the hatchery.
It works. “Larvae take three to nine years to metamorphose, so we're just starting to get the adults out of the ocean from the juveniles we stock,” says Ralph Lampman, a biologist at the Yakama Lamprey Project. "We had 20 adults in 2020, but more than 500 in 2022." He expects much more this year. In 2023, the peak will be in July.
On both coasts, the biggest educational challenge is in Vermont, as the state kills lampreys with one hand and restores them with the other. In Lake Champlain, Vermont, lampreys are being poisoned extensively with TFM. This is necessary because even though lampreys are native to Champlain, if left unchecked they would destroy hatchery-raised salmon and lake trout strains that did not co-evolve with them and replace native strains long wiped out by dams, pollution, and fishing. predatory.
But in the Connecticut River system, Vermont is involved in similarly intensive recovery of lampreys, establishing traditional spawning habitats and opening up known habitats by removing impassable dams and channels.
Fishery biologist Lael Will of Vermont keeps getting reports of people going "crazy" when they see lampreys in tributaries of the Connecticut River, then grab them and throw them onto the beach. She gives presentations explaining that in freshwater native lampreys help aquatic and terrestrial wildlife and cannot mate with humans or fish. And she issues press releases urging the public to leave native lampreys alone. Her message, she reports, is "starting to catch on".
“I'm sorry if house lampreys scare people,” declares Will, “but everybody has to earn a living. These guys just make a living in a different way.”