Lake Superior trout harvest cut as lamprey reduce population
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Anglers won't be able to catch as many lake trout in the Apostle Islands region of Lake Superior after the Natural Resources Board approved a 15% cut in the harvest.
The cut comes as the population of lake trout is at its lowest point in three decades, according to state data.
The Wisconsin Department of Natural Resources requested a reduced harvest of 57,000 lake trout for the 2027 season as fewer young fish are surviving to adulthood amid higher numbers of invasive sea lamprey. It's an eel-like parasites that sucks the blood of its hosts.
The reduction affects waters between Bark Point and Saxon Harbor on Lake Superior.
The DNR and the Red Cliff and Bad River Bands of Lake Superior Chippewa jointly manage fish populations in Lake Superior under a 10-year fishing agreement. The harvest would be split, with 39,500 fish going to tribal anglers and 17,500 fish split between state commercial and sport anglers.
Most recent data for lake trout indicates the population has been declining since 2020, said Brad Ray, the DNR's Lake Superior fisheries team supervisor. Modeling conducted by the DNR shows a nearly 37% decline in the estimated lake trout population, falling from roughly 835,000 to about 530,000 between 2020 and 2025.
"We're just not having any fish coming back into the fishable population, so there's no young fish out there," Ray said.
The DNR's modeling shows the population peaked at around 930,000 fish in 2002.
Ray said lake trout mortality rates have nearly tripled in the last four years due to higher sea lamprey numbers. He attributed that to missed treatments to control the fish-killing invader during the COVID-19 pandemic. The primary method to control sea lampreys is lampricide, a chemical that's applied at very low levels to kill lamprey in streams before they migrate into the lake to feed.
In Lake Superior, the Great Lakes Fishery Commission said the estimated number of sea lamprey dropped from over 40,000 last year to just under 30,000 this year. Despite the decline, the fish-killing invader is still above the management goal of around 10,000.
"We're still way higher than we want to be," Ray said of lamprey numbers. "We don't really have a great idea of what might have been causing this lower recruitment, but we're working on that. Biological staff of Red Cliff, Bad River and the state are looking into that."
Ray said their hope is that the decline stems from higher lamprey numbers that could be reduced with additional treatment.
Paul Reith, chair of the Wisconsin Conservation Congress, backed the reduced harvest. He noted the state's share of the harvest is down 22% and creates a notable impact on commercial fishers, sports anglers, charter and guide businesses that rely on the fishery.
"Recruitment is low. Sea lamprey pressure is high. Acting now while we can protects the fishery for the long run," Reith said. "It's far better to take a measured step today than to face much harsher restrictions later."
Craig Hoopman, chair of the Lake Superior Commercial Fishing Board, agreed that it's best to err on the side of caution. Hoopman said he fished over three licenses between April and the end of August, and he harvested a little more than 600 lake trout.
"I'm as confused as everyone else is. We went from basically in a little over a year seeing what we all would like to refer to as historic numbers, and it was just great. There was fish everywhere," Hoopman said. "Then in a short window of opportunity, I fished a lot of areas, and these fish just simply aren't there."
Just two years ago, fishery managers were celebrating a full recovery of lake trout in Lake Superior. Ray said the growth in sea lamprey numbers had the biggest effect on numbers in the last two years.
The lake trout population in Lake Superior dropped to dramatically low levels during the mid-1900s due to overfishing and an invasion of sea lamprey. The parasitic fish spread to the Great Lakes from the Atlantic Ocean, invading Lake Superior by 1938.
The Great Lakes Fishery Commission has committees that oversee the Great Lakes. Ray said they've been talking with the U.S. Fish and Wildlife Service about increasing sea lamprey treatments.
Sea lamprey numbers are not as high in Wisconsin waters on the western edge of Lake Superior extending from Bark Point to Superior. The harvest there would remain unchanged at 14,000 lake trout. State and recreational anglers receive the vast majority of that quota.
Ray said state anglers harvest an average of 30,000 pounds of lake trout each year in Wisconsin waters of Lake Superior.
The 2027 season begins on Nov. 28.