Lake Superior’s top predator fish is at a sustainable population. The lake trout population has recovered to the point it no longer has to be stocked. The fish had dropped to extremely low levels.

Ever since European settlement, overfishing took a vast toll on lake trout in Lake Superior. Then the invasive sea lamprey, a parasite, nearly wiped out the population by the 1990s. It took the states, tribes, Ontario, and the two nations decades to come to an agreement that would eventually restore the lake trout.

“We have the largest freshwater lake in the world, the top species in that freshwater lake that was driven down 95 percent because of overfishing and lamprey predation, today declared restored,” said Marc Gaden, executive secretary of the Great Lakes Fishery Commission. That organization is primarily known for controlling the invasive sea lamprey population.

The Lake Superior Committee made the announcement about the milestone. That committee, coordinated under the auspices of the Great Lakes Fishery Commission, consists of fishery managers from three of the Great Lakes states that border Lake Superior (Michigan, Wisconsin, and Minnesota), the Province of Ontario, and the U.S. Tribes represented by the 1854 Treaty Authority, Chippewa-Ottawa Resource Authority, Great Lakes Indian Fish and Wildlife Commission, and the Red Cliff Band of Lake Superior Chippewa Indians, according to a news release by the committee.

Not just number, but diversity

Gaden said the sustainability milestone is not just about the increased number of lake trout; it’s also about diversity. He said the different subspecies — lean trout, humper trout, and siscowet — have all recovered to sustainable levels.

Between 1920 and 1950, an annual commercial harvest of 4 million pounds was taken, according to the fishery commission. By 1964, the harvest was down to 210,000 pounds.

The Lake Superior Committee estimates the current abundance of naturally reproduced lake trout is at or above the estimates prior to the sea lamprey invasion that reached Lake Superior in 1938.