We all enjoy watching the widlife go about their daily activities. However, scientists say our mild winters and extreme weather is showing a shift in the wildlife patterns. They see this shift in the number of fish in our lakes, and different animals moving further north.

FISH

Alex Latzka is a Biologist for the Wisconsin DNR Fisheries. Latzka says as area lakes get warmer, the ice also melts earlier. “It doesn’t fit the walleye spawning routine,” he said.

“As lakes are getting warmer, and ice is coming off the lakes earlier, the walleye spawning normally would happen shortly after the ice comes off. It’s not keeping up,” Latzka said. “They’re not adapting quickly enough to the kind of spawn and have the eggs hatch at the same time.”

He said where we see a change is after the eggs hatch between late spring, early summer and the fall.

“All the young that hatch from those eggs, often don’t survive,” Latzka said. “So we have these kind of failed reproduction events where they did reproduce, just the young didn’t survive.”

But what does that do to the overall reproduction of walleye?

According to Latzka, a lot of walleye populations are struggling to keep up. “Certain lakes, especially smaller lakes, lakes that aren’t connected to as big of rivers where natural reproduction in most years is not succeeding at nearly the rate we saw 20-30 years ago.” Latzka says the consequence of this, is the populations.

Walleye populations aren’t the only concern, lake trout are too.

“You know, as temperatures increase in the air, then our lakes and stream temperatures can increase and in these years, when we get these crazy precipitation events, it can lead to extreme flooding, especially in our rivers and streams,” says Alex.

Mike Rackouski an Advanced Fisheries Technician at the Les Voight Fish Hatchery in Bayfield, Wisconsin says that dry conditions and flooding conditions can ruin fish spawning grounds. “If the water is too high, it can wipe out the young fish that are in the system presently,” Rackouski says.

Dr. Jonathan Martin a University of Wisconsin Atmospheric Professor says, “If this begins to be the normal, then ecosystems and commerce and lots of other things are going to start to be affected in ways that we maybe should try to get ahead of.”

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Places like the fish hatchery are already doing their part. The hatchery was built in the late 1800s to help stabilize the population of fish even during extreme conditions.

“We’re stocking presently 60,000 yearling lake trout into western Lake Superior, just outside the city of Superior. And that program is to re-establish the lake trout population,” Rackouski said.

WILDLIFE

Fish populations aren’t the only wildlife being affected Dr. Michael Joyce a wildlife ecologist at the Natural Resources Research Institute says newer species are migrating northward.

“We’re working a study on flying squirrels right now as well, which is really heavily tied to climate and how things have changed. We see them moving north and, in some cases, out competing with our northern species and pushing them farther north.” says Joyce.

Joyce says other examples would be more possums, grey fox, bob cats, and a larger number of turkeys. Other concerns include reproduction rates of Canadian geese and swans.

“The concern with them is that when we get this warmth earlier, a lot of their food sources especially insect food sources, come out earlier,” he says. “They’re historically their migration timing coincides with the peak of insect density out. So, they really need those food resources for successful reproduction.”

If you are wondering if there is anything we can do to help?

Dr. Martin says, “We have to start trusting our own senses a little bit more and rely on experts for the details. But trust our own senses. That combination is quite powerful, and it’s done our country well for 250 years.”