MINNEAPOLIS (AP) — Climate change threatens Minnesota’s prized fisheries from North Shore trout streams to popular walleye lakes such as Mille Lacs, experts said Wednesday as the National Wildlife Federation released a national study on the risks to freshwater fish in a warming world.

“It is clear that climate change is creating new stresses on fish, whether brook trout in Appalachia, walleye in the Midwest, Apache trout in the arid Southwest, or salmon in the Pacific Northwest,” the report said.

And it’s not just summer fishing that’s at risk. The report said the Midwest’s ice fishing tradition could melt away because lakes are slower to freeze and quicker to thaw.

Study co-author Doug Inkley said 37 percent of all freshwater aquatic animal species are at risk, and the country needs to address the root cause by cutting carbon dioxide pollution. But he said other necessary steps include safeguarding fish and their habitats from climate change, such as by restoring forests upstream and protecting wetlands and flood plains to improve water quality. Another strategy is to use water more wisely, he said, especially where it’s in short supply.

Inkley spoke about the report on a conference call with Minnesota reporters, joined by Don Pereira, fisheries research and policy manager for the Minnesota Department of Natural Resources, John Lenczewski , executive director of Trout Unlimited Minnesota, and Gary Botzek, executive director of the Minnesota Conservation Federation.

“Fishing is indeed a big deal in Minnesota,” Botzek said, noting that it’s a $2.8 billion industry in a state where 1.5 million people fish recreationally. “it’s an integral part of being a Minnesotan.”

Pereira said warmer water is contributing to the decline of ciscoes, also known as tullibees or lake herring, an important forage fish for walleyes and northern pike. The species is found in over 600 Minnesota lakes. He said research indicates that if carbon dioxide levels continue to rise, ciscoes might survive in about 200 of those lakes, but only if they’re kept clean. They’ll likely endure in big lakes in far northern Minnesota such as Lake of the Woods and Vermilion, he said, but maybe not in shallower lakes to the south.

“If climate change continues I don’t see cisco persisting in Mille Lacs decades from now,” Pereira said.

Lenczewski said safeguarding forests is critical to protecting northern Minnesota’s trout streams. Managing forests to keep them more mature would slow the melting of snow in the winter and runoff from summer rainfall so that they release water into streams gradually rather than all at once, he said.

Smarter use of groundwater is also important because underground springs help keep trout streams cold in other parts of Minnesota, Lenczewski said. He pointed to DNR plans to create groundwater management areas in two agricultural regions to try to limit depletion from irrigation, including the Straight River area near Park Rapids.

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