Seen On

Good Question: Will Climate Change Affect Fishing?

(WCCO) For more than 50 years, the governor's fishing opener has been a major part of life in Minnesota. According to the Minnesota Department of Natural Resources, more than a million of us buy fishing licenses every year, and hit the lakes.

However, state researchers are beginning to track a slow and subtle change below the surface of the water. Fisheries biologists are looking into what will happen if the state's lakes warm as a result of climate change

"Nobody's got all the answers, that's the problem," said Dick Sternberg, a former fisheries biologist for the Minnesota DNR As for climate change, Sternberg calls it "a concern."

"Climate scientists from across the globe are virtually certain that concentrations of greenhouse gases in the atmosphere will lead to warmer temperatures in the next 50 years," said Don Pereira, fisheries research manager with the Department of Natural Resources, in an article in the May-June 2008 issue of "Minnesota Conservation".

"Given that, we need to begin thinking about adapting our fisheries management to a warmer climate," added Pereira.

According to the current theories of the DNR and Sternberg, warmer lakes could be a good thing for walleye and northern pike.

This year the ice melt was far later than normal, but as the climate warms, ice melt should happen earlier and earlier. That would give walleye and northern pike more time to reproduce before the start of the fishing season. That would be good for those fish populations.

However, warming could be bad news for cold weather fish like the tullibee, which is the food for the larger walleye and northern pike.

"It's good for one and not so good for the others," said Sternberg.

He believes that a subtle change of a degree or two wouldn't make much of a difference in the fish stock of a lake.

"But when you start getting up to five degrees? When you start losing that layer of cool water in the bottom of the lake, and that can have some real significance," he said.

Periera is starting a four-year research study in conjunction with the Minnesota Pollution Control Agency at two dozen lakes. The DNR and PCA will take water samples to try and determine what, if any, impact climate change is having.

Sternberg expects climate change to force the DNR to do more stocking of lakes where the weather conditions formerly were suitable for natural spawning.

According to Sternberg, in Minnesota, there are about 1,700 lakes where walleye naturally reproduce and 1,700 where the DNR has to stock the lakes. He expects that ratio will change if the climate continues to warm.

"They're still trying to figure this out, they don't know exactly what this means," said Sternberg. "The lakes are fully capable of growing walleyes. In fact, they'll probably grow them faster than they did before because the water's warmer."

 

(© MMVIII, CBS Broadcasting Inc. All Rights Reserved.)