Thursday, September 26, 2024
PESHTIGO – The U.S. Fish and Wildlife Service’s visit to Peshtigo and Oconto rivers this month wasn’t a pleasure trip.
Agency workers applied a chemical treatment to kill Sea Lamprey larvae and prevent the invasive species from taking over Lake Michigan. The use of poison startled some.
A Facebook post by Rebecca LaCoy said, “Poison was dumped in the Peshtigo River on Friday….It’s killing many different fish species, many different trout, walleyes and salmon. They have not tested the fish to see if they are safe to eat. The birds are not eating the dead fish.”
“We were doing a Sea Lamprey treatment. We typically do that every three to four years,” said Chris Gagnon, supervisory fish biologist with the U.S. Fish and Wildlife Service in Marquette, Michigan. The 56,489 Sea Lamprey larvae in the Peshtigo River and 52,172 larvae in the Oconto River with lampricide treatments between Sept. 10 and Sept. 19.
The U.S. Fish and Wildlife Service started on the Peshtigo River Friday morning, Sept. 13, and finished Saturday morning, for about 12 hours of application, Gagnon said. “Every river is different. Some take five or six days,” he said.
“We try to keep the Sea Lamprey levels low so all of the Great Lakes fish can be healthy,” he said.
Sea Lamprey are also called vampire fish because they suck on the sides of other fish, removing the fluids from healthy fish and killing them. “said Greg McClinchey, director of policy and legislative affairs at the Great Lakes Fishery Commission, based in Ann Arbor, Michigan. “They’re an ancient fish – 350 million years old,” he said.
The binational commission coordinates fisheries management in the Great Lakes in the United States and Canada. It works with other agencies to do the lampricide treatments.
The U.S. Fish and Wildlife Service primarily uses two lampricides -- TFM (3-trifluoromethyl-4-nitrophenol) and Bayluscide (dichloro-nitrosalicylanilide) – to kill Sea Lamprey larvae up to six inches long, Gagnon said.
“Sea Lamprey can’t detoxify the chemical very quickly and other fish can,” he said. But the lampricide also can affect other fish, he said. “To be honest, we were under the assumption we would kill some of the other fish,” Gagnon said.
When the agency arrived at the Peshtigo River, it found hundreds of spawning pink salmon —and a few dead fish. “When we get to the river here, there was a lot of spawning pink salmon. There was already a few dead fish before we did the treatment,” he said.
“We walked the river and we collected 64 dead pink salmon — adults coming up to spawn,” he said. “There were thousands of pink salmon in the river. A lot were congregated in the damn below the Peshtigo River.”
Other experts, however, said the treatment shouldn’t affect other fish because Sea Lamprey can’t metabolize the compound but other fish can. “That’s the beauty of it. It attacks Sea Lamprey without causing damage to other fish,” McClinchey said.
The lampricide compounds biodegrade in a couple of hours, McClinchey said. They’re designed to kill Sea Lamprey larvae before they go out from the rivers to the lakes to do their damage, he said.
McClinchey said he would be very surprised if the treatment in Peshtigo caused the dead fish spotted on the side of the river. “That would be highly unusual,” he said. “It would not be noral at all to kill other fish. It’s not typically harmful to fish” other than Sea Lamprey and perhaps Salamander, he said.
Dams and electric barriers also are used to control Sea Lamprey, which migrated from the Atlantic Ocean to the Great Lakes over 100 years ago, he said. When they arrived in the Great Lakes, the fish population plummeted due to damage from the lamprey, which thrive in fresh water rivers. Females have about 100,000 eggs, and a mature Sea Lamprey will eat about 40 pounds of fish, he said.
“Their populations are down about 90 percent, but we can’t let up on it because they rebound so quickly,” McClinchey said. During the Covid-19 pandemic, the commission’s lampricide program was put on hold for about two years. “We saw huge spikes in populations in some areas,” he said.
In the United States, the program is federally funded through a federal law called the Great Lakes Restoration Initiative. The U.S. EPA allocates funds to federal and state agencies to control invasive species, including sea lampreys, according to a Sept. 25, 2023 Congressional Research Service article. In 2021, Congress provided for an annual increase from $375 million in fiscal 2022 to $475 million in fiscal 2026 for this program. Other federal funds come from appropriations to the U.S. Fish and Wildlife Service’s Fish and Aquatic Conservation program.
The Great Lakes Fishery Commission issues public notices about the lampricide treatments, McClinchey said, but no one contacted for this story was aware of any notice or signage about the local treatments. “We contract with government agencies to do the treatments; in this case, U.S. Fish and Wildlife Service.” The agencies workers are expected to let people in the local area know about the lampricide treatments, he said.
The City of Peshtigo Public Works Director Matt Decur told a reporter he was notified of the U.S. Fish and Wildlife Service’ treatment, but the city isn’t involved with it. He wasn’t aware of any danger to the water supply or fish in surrounding water.
“The DNR would be posting any recommendations for the eating of the fish,” he said.
Local municipalities are required to test drinking water for several chemicals, such as disinfection byproducts, copper, lead and radium, Decur said, but not for lampricides.
A fact sheet found on the U.S. Fish and Wildlife Service website suggests lampricides in pure form are toxic and care should be used around them. If swallowed or contaminated with the chemicals, people are instructed to call a poison control center or doctor immediately. If the chemicals get on clothing, take off the garments and rinse your skin with water for 15 to 20 minutes, the notice said. Rinsing with water also is recommended if the lampricide gets in your eyes.
Gagnon said a treatment consisting of TFM and Bayluscide was applied for about 12 hours to the Peshtigo River about 100 feet below the dam, to avoid exposing the salmon to the chemical.
“After that 12 hours is past, we have water samplers throughout the system. We’re taking water samples throughout treatment. It passes really quick. We can show it goes down to zero pretty quick,” he said. The chemicals are biodegradable, Gagnon said.
Sean Strom, a fish and wildlife toxicologist at the Wisconsin Department of Natural Resources, said the agency isn’t directly involved with the treatment, but U.S. Fish and Wild Life Service notifies the DNR when it applies for a permit to treat the area.
TFM doesn’t accumulate in other fish species, he said. “Most of it is flushed through the fish in a day’s time,” he said.
Log perch and mud puppies also are sensitive to the chemical, Gagnon said.
“We do treatments all summer long, as long as the fish are healthy. Most of the time everything is fine,” he said. The U.S. Fish and Wildlife Service started on the Peshtigo River Friday morning, Sept. 13, and finished Saturday morning, for about 12 hours of application, Gagnon said. “Every river is different. Some take five or six days,” he said.
Lake Sturgeon are a protected species, so the USFWS is careful to avoid treatments in the spring when the Lake Sturgeon are coming up river to spawn, Gagnon said. “We don’t want to have a mortality of Lake Sturgeon,” he said.
The program began in the 1960s, he said. Before then, the Sea Lamprey were wiping out Lake Trout and other more desirable fish in the Great Lakes, Gagnon said.
The Sea Lamprey make their way to Michigan and Wisconsin by traveling through the Welland Canal near Niagara Falls. “When we built the canal around Niagara Falls, they were able to get to the Great Lakes,” he said. Federal funds for treatments aim to stop them from taking over.
