Let's be clear up front: Fisheries scientists say there are many factors that may be affecting the walleye population in lakes like Mille Lacs. Overfishing, invasive species like zebra mussels and increased predators feeding on young walleyes may all play a role.
That said, big, shallow lakes like Mille Lacs are a special laboratory for Minnesota's warming climate. They can be more sensitive to temperature changes than deeper lakes. There's also evidence that some fish that are critical food for walleye, like the cisco, are very sensitive to warmer water in summer.
Peter Jacobson, a habitat group supervisor with the Minnesota DNR Fisheries Research, and John Lenczewski, the executive director of Minnesota Trout Unlimited, joined MPR News chief meteorologist Paul Huttner to discuss the issue.
Jacobson acknowledged that while cisco may be affected by warming temperatures, climate conditions for walleye in Mille Lacs and other lakes around the state remain positive.
"Conditions are still good for walleyes, walleye reproduction and the walleye population itself in Mille Lacs," Jacobson said. Other species, however, have seen different effects. Lenczewski said recent weather developments have had ramifications for trout fishermen.
"We do see the changes as far as timing for fishing runs — the steelhead season, that is shifting dramatically," Lenczewski said. "We are left with a longer period of low, warm summer flows, and that is having an impact on brook trout and steelhead on the North Shore."
Dramatic floods have also affected fish habitat. "The June 2012 floods in Northeastern Minnesota are a good example of one of those unprecedented severe rainfall events," Lenczewski said. "The flooding from that absolutely destroyed habitat in dozens of key rivers."
For the full discussion on climate change and fishing in Minnesota, use the audio player above.