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The Great Sea Lamprey Fiasco

The Premise

Once heralded as the "greatest invasive species control success story" for its perceived role in restoring the collapsed Great Lakes fishery, scientists are now implicating the US Fish and Wildlife Service's use of the chemical lampricide TFM in the mass deaths of native species from mussels to mudpuppies. Environmental activists and ecologists are calling for an end to TFM treatments in favor of alternative sea lamprey controls. 

The Sea Lamprey

Native to the Atlantic Ocean, sea lampreys were first recorded in the upper Great Lakes in the 1920s, following the construction of the Welland Canal which bypassed their natural barrier, Niagara Falls. The sea lamprey’s elongate and slimy body may look eel-like, but it belongs to a much older group of jawless fish which first appeared 360 million years ago. During their first three to ten years of life, sea lamprey larvae (called ammocetes) filter feed in river sediment.


Following a mysterious trigger, they burst into the water column, develop beady eyes, a suction cup mouth filled with rows of sharp teeth, and a rasping tongue. Then, they travel downstream to the Great Lakes where they spend the next twelve to eighteen months feeding off the blood and body fluids of native fish species.


The Problem

Prior to sea lamprey invasion, the United States and Canada fisheries were estimated to harvest 15 million pounds of lake trout (Salvelinus namaycush) every year. By the 1960s, harvests had declined by 98%. The coinciding boom in the sea lamprey population was seen as a smoking gun, and the species was widely blamed for the fishery’s collapse.


A Treaty is Signed

A treaty between the United States and Canada established the Great Lakes Fisheries Commission in 1954 with the primary goal of eradicating sea lamprey populations. In 1958, it was discovered that 3-trifluoromethyl-4-nitrophenol or TFM is highly toxic to sea lamprey while being less toxic to non-target organisms at the same concentrations. Exposure to TFM starves a sea lamprey’s cells of energy and rapidly leads to death.

Today, the US Fish and Wildlife Service and Fisheries and Oceans Canada partner with the Great Lakes Fisheries Commission to apply TFM to approximately 500 Great Lakes tributaries on a three-to-five-year basis. The use of TFM is credited with the recovery of game fish populations as well as a 90% reduction in the population of sea lampreys. “It [TFM] really is miraculous,” says Marc Gaden, the communications director and legislative liaison for the Fisheries Commission. “We would give anything to have something even half as good for Asian carp, zebra mussels, or round gobies.”


The Risk

Proponents of TFM praise its apparent selective toxicity for sea lampreys. While he admits non-target mortality does occur, its “extremely rare,” says Marc Gaden. Researchers monitoring the immediate aftermath of TFM treatments tell a different story, however. 

Dr. Tim Matson

Every summer for the last thirty years, Dr. Timothy Matson has returned to a thin strip of gravel in the middle of Ohio’s Grand River just below Lake Erie’s central basin. Even in his first year of retirement after forty-five years as Curator of Vertebrate Zoology at the Cleveland Museum of Natural History, Matson’s research hasn’t slowed down in the slightest. The 60-something-year-old stands tall and thin, knees locked together like a toy soldier. With his neatly combed, gray hair and mustache, blue collared shirt, and matching slacks, he looks more prepared to deliver a lecture than to wade chest deep into the nearest river.

Matson’s obsession with TFM first began in 1987, when the US Fish and Wildlife Service treated Conneaut Creek, a nearby tributary, for the first time. “There was so much mortality,” Tim says, and he has the jars of preserved specimens to prove it. “TFM doesn’t just kill lampreys, it kills everything.”