The Wisconsin Department of Natural Resources (DNR) has proposed a major reduction in the commercial harvest of lake whitefish from Lake Michigan following steep population declines over the past two decades.

According to Wisconsin Public Radio, the DNR estimates the lake’s whitefish population, which was once more than 60 million fish aged three years or older, has dropped by more than 75 percent. “It’s ultimately about keeping the fisheries sustainable and keeping the population sustainable based on what is happening in Lake Michigan right now,” said Scott Hansen, senior fisheries biologist for the DNR.

To address the decline, the agency is seeking public input on a proposal to cut the commercial whitefish quota from about 874,000 pounds to just under 535,000 pounds next year- a reduction of nearly 340,000 pounds. The public comment period runs through November 7, with a final recommendation expected to go before the state’s DNR board in December.

The whitefish fishery, valued at roughly $2.8 million last year, has long been the most valuable commercial fishery on Lake Michigan. However, harvests have fallen sharply from a peak of about 2 million pounds in 1999 to only 150,000 pounds in 2024.

Both regulators and fishermen point to invasive zebra and quagga mussels as key drivers of collapse. Tood Stuth, who operated Baileys Harbor Fish Company in Door County with his wife Carin, said the mussels have filtered out many of the organisms young whitefish rely on. “It’s not a fishing impact,” Stuth told Wisconsin Public Radio. “It’s basically a complete ecologically based decline in whitefish stocks.”

Even so, Hansen said that fishing pressure remains a factor. It has been about 20 years since the lake last had a strong whitefish spawning year class.

On the other hand, Green Bay’s whitefish population has remained relatively stable, with the DNR keeping its commercial quota steady at 1.1 million pounds. Still, Hansen said models show even Green Bay’s mature whitefish numbers have declined by more than half from their 2011 peak.

For the fishermen, sustainability remains the top priority. Stuth told sources, “At some point, you have to realize that you have to do some things that are not always favorable in terms of your business, but it is favorable in terms of the resource. Sustainability is the key to any long-lasting commercial fishery.”