Outdoor groups say hunters and anglers in Minnesota are observing the effects of global warming.
Minnesota Trout Unlimited Director John Lenczewski said recent research shows that in southeast Minnesota trout streams, insects that are a key part of the food chain are easily harmed by warmer-than-normal weather.
"We need cold winters to have these bugs in the stream," Lenczewski said. "They'll generate several broods of insects, but it's critical wintertime feed for trout down there, and it doesn't take much. They've shown just a few degrees increases in temperature and we won't see those insect species anymore."
Lenczewski said along the North Shore of Lake Superior, a quick snow melt results in longer periods of low water volumes, which harms trout populations.