Keeping lampreys out of the lake
USFWS conducts treatment
MARQUETTE — In itself, the sea lamprey is a fascinating animal. It resembles an eel, has a suction disk mouth filed with rasping teeth, and can live in salt and fresh water.
Unfortunately, it does not belong in the Great Lakes because of its ability to decimate native fish populations because of its parasitic qualities.
To control sea lampreys, the U.S. Fish and Wildlife Service applied lampricide in Morgan Creek, a tributary of the Carp River, this week to kill lamprey larvae burrowed in the stream bottom.
Participating in the project was Chris Gagnon, supervisory fish biologist with the U.S. Fish and Wildlife Service.
The treatment is an ongoing effort on the Carp River.
“We do this every three years to rid the juvenile sea lamprey from the stream,” Gagnon said. “They live about four years as harmless larvae in the stream, so we have until that four years until they turn into parasitic adults and go into the lake.”
By lake, he meant Lake Superior — a body of water not meant for sea lampreys.
Gagnon said the lampricide TFM, which stands for 3-trifluoromethyl-4-nitrophenol, was used.
“When put in the right amount, it kills the sea lamprey, and it has little or no effect on any of the aquatic life in the river,” Gagnon said.
Lamprey treatments, he noted, has been going on since the 1950s.
“We’ve done a really good job of keeping them under control, well below their levels seen in the ’50s and 60s,” Gagnon said. “That’s what our job is — is just keep them at incredibly low levels so that the fisheries can thrive with what we’re doing.”
Lampreys prefer soft-scaled fish such as lake trout, although they will eat pretty much anything to which they can attach: whitefish, sturgeon, walleye, northern pike “or anything they can get a hold of,” he said.
Sea lampreys entered the Great Lakes from the Atlantic Ocean through manmade shipping canals in the 1800s, the Great Lakes Fishery Commission said. Before the Welland Canal opened in 1829 and prior to its modification in 1919, Niagara Falls served as a natural barrier to keep lampreys out of the upper Great Lakes. Sea lampreys were first observed in Lake Ontario in the 1830s, and were seen in Lake Superior in 1938.
By the late 1940s, lamprey populations had ballooned in all the upper Great Lakes, causing severe damage to the lake trout fishery as well as other fish species.
Gagnon said the USFWS has larval assessment crews that determine lampreys’ locations and how far up the stream they traveled so only a particular portion of the stream is treated. Any additional fresh water coming in, such as Morgan Creek, with no indication of sea lampreys has to be treated.
“It’s not positive for the sea lamprey, but we still have to apply the TFM near the mouth just to account for the water, so we keep our concentrations at a certain point,” Gagnon said.
He agrees that the sea lamprey is a unique creature.
“You have to respect them for what they’re able to do,” Gagnon said. “The Great Lakes just happened to be a great spot for them to thrive in. They adapted to life in fresh water.”
According to the USFWS, the Environmental Protection Agency and the Health Canada Pest Management Regulatory Agency have reviewed human health and environmental safety data for lampricides, and in 2003 concluded that certain lampricides pose no unreasonable risk to the general population and the environment when applied at concentrations necessary to control larval sea lampreys.
The program is contracted through the GLFC to the USFWS as well as Fisheries and Oceans Canada. The commission initiated chemical control of sea lampreys in 1958.
Since then, program has contributed significantly to the maintenance of the $7 billion Great Lakes sport and commercial fisheries.
To support the continued safe use of lampricides, the commission recently conducted a series of studies at a total cost of $6 million to assess the effects of the lampricides on human health and the environment. In addition to these studies, the commission has implemented a research program to develop alternative control techniques.
The commission also is developing a strategy to increase the number of barriers on lamprey-producing streams, and is conducting research into barrier design, traps, attractants and biological controls.
Gagnon said the COVID-19 pandemic affected local lamprey-control efforts during what he called a “weird year” that’s led staff to treating streams out of its Marquette Township office due to travel restrictions. Usually they travel around the Upper Peninsula and Wisconsin to treat streams, he said, although some near Escanaba and near Houghton are being treated.
Before a stream such as Morgan Creek is treated, the USFWS performs two or three days of preliminary data collection because pH drives how much chemical is put in the water to make it effective with “non-target effects,” Gagnon said.
Dan Kochanski, USFWS physical science technician, was at the Morgan Creek site to check water chemistry — an important activity to keep people and the environment safe.
“I’m monitoring how our chemical is affecting the water, and we adjust our chemical based on those chemistries to keep the fish and insects but still kill the lamprey,” Kochanski said.
Applying the chemical to Morgan Creek was Cory Racine, biological science technician with the USFWS.
“My job is basically to make sure that we’re achieving the rate he needs to get the right concentration so we’re killing the lamprey but keeping all the natural fish in this creek safe,” Racine said.
The setup, he noted, is simple: an electric pump goes to a spreader bar, with a butterfly valve there so he can perform a feed check.
Gagnon said the Laughing Whitefish River near Deerton also was treated recently.
“That was a successful treatment,” he said. “Quite a few sea lamprey were in there.”