Study planned on walleyes, predators in northern Wisconsin Milwaukee. Journal Sentinel 1/29 2017 ..
University researchers plan to start a study this year on the predatory effect of young panfish and largemouth bass on the walleye population in a northern Wisconsin lake.
To do so, they propose to remove large numbers of small panfish and bass by hook-and-line fishing, electro-shocking and fyke netting.
The captured fish would be transferred live to a nearby lake.
The researchers would then monitor the fish population in the study lake. Of primary interest: walleye recruitment, or the number of naturally reproduced walleyes that survive to age 1.
Fisheries biologists know young panfish and bass prey on walleye fry. Over time, the predation could transform a walleye-dominated lake to one dominated by panfish and bass.
The researchers hypothesize that by removing significant numbers of young panfish and bass, natural reproduction of walleyes will increase and possibly lead to strong year-classes of walleyes.
The study is a joint effort of the University of Wisconsin, UW-Stevens Point and the Wisconsin Department of Natural Resources.
The universities have received a $1 million grant for the study from the U.S. Geological Survey.
Steve Carpenter, director of the Center for Limnology at UW, is leading the project.
"We've known for more than a decade that walleye populations are declining in hundreds of northern lakes," Carpenter said. "There are likely several factors involved, but we're still trying to find out which are most important and if there is a strategy toward long-term walleye restoration."
Past research has shown climate change is having a detrimental impact on walleyes. Shoreline development and habitat loss are also proven to negatively effect walleye populations.
Attempts to improve walleye populations have included habitat work, stocking and regulation changes. While some lakes have benefited, fisheries managers and researchers have yet to find a “cure-all” solution to improving walleye populations, Carpenter said.
After considerable conversation between researchers and fisheries biologists in the Upper Midwest, Carpenter said it was decided a predator removal experiment should be conducted to target the small predators.
"Mature bass likely aren't the problem," Carpenter said. "But all the small bass and small panfish in a lake are prime predators of walleye fry. That's what we want to look closely at."
The work is planned for one lake and would last for four or five years. Depending on early results, Carpenter said he'd like to apply for more funding to extend the study for eight to 10 years.
One or two reference lakes in the area would be used to study the fish communities for any weather-related or other changes over the study period.
Removing thousands of small bluegills, pumkinseed sunfish and juvenile bass is a daunting undertaking. Carpenter said the work would enlist "hard-working undergraduates who love to fish" as well as nets and electro-shocking.
The predator removal work would be repeated annually.
The main goals of the experiment would be to: reduce the numbers of largemouth bass and sunfish; improve walleye spawning and survival; and ultimately increase the numbers of adult walleye in the selected lake.
A DNR permit will be required to conduct the study.
The researchers have identified nine candidate lakes; the study lake will be chosen with help from public input.
Meetings will be held from 6:30 to 8 p.m. Monday in at the Minocqua Public Library and 6:30 to 8 Tuesday at the Hayward Veteran's Center.
"We've gotten a lot of encouraging response from the public so far," Carpenter said. "We're excited to get this going."
Whitefish survey: The DNR is soliciting public comments through Feb. 10 on Green Bay whitefish management. After receiving strong public opposition, the agency last year shelved a proposal that could have increased commercial fishing for whitefish and allowed netters to keep walleyes in southern Green Bay. The DNR has a survey on dnr.wi.gov under search words "whitefish management." Or written comments can be mailed to David Boyarski, WDNR, 110 S Neenah Ave., Sturgeon Bay, WI 54235.