Giving walleye a fighting chance: “Hidden overharvest” affecting fish population

Alex Bentz, field technician at the the Wisconsin Department of Natural Resources holds a walleye. Photo by Adam Hinterthuer, UW–Madison Center for Limnology
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MADISON, Wis. (WMTV) -- A popular fish with Wisconsin anglers is getting harder to find on some of the state’s lakes.

A study recently released from UW-Madison shows walleye populations have been on a downward trend in the last few decades.

"Forty percent of walleye populations are overharvested, which is ten times higher than the estimates fisheries managers currently use," said Holly Embke, UW-Madison Center for Limnology graduate student. “A big reason for this ‘hidden overharvest’ is that, for the last 30 years, resource managers have focused on fish abundance and not fishery productivity when calculating harvest limits. “

In the late 1980s, the Wisconsin Department of Natural Resources (DNR) and the Great Lakes Indian Fish and Wildlife Commission set regulations that ensured a maximum harvest amount of 35 percent of the adult walleye in any given lake.

“These regulations worked for a long time, and then they stopped working," said Steve Carpenter, director emeritus of the Center for Limnology, "Over the last couple of decades, there began to be walleye recruitment failures scattered around the state."

The study found in the last few decades, annual walleye production declined by 35 percent. Walleye stocks also take one and a half times longer to replenish compared to 1990 data.

The study also found variations in walleye production from lake to lake. Some lakes remain walleye strongholds and can handle current fishing pressures, while others can't sustain current average harvest rates of 15 to 20 percent, much less the 35 percent harvest benchmark.

Researchers say the study shows there needs to be improved governance, assessment, and regulation of recreational fisheries.

“By better understanding the resilience of Wisconsin walleye populations and by acknowledging the role that anglers play in reducing stocks, the future of this iconic fishery just may have a fighting chance,” Carpenter said.