Smith: Walleye decline spotlight on Lac Vieux Desert

Fun to catch and unsurpassed as table fare, the walleye is widely considered the favorite fish of Wisconsin anglers.

Its popularity comes with a cost, however. On many waters, the fish has been over harvested.

And in recent years, concern is growing over other, perhaps greater, risks facing the species.

One of the latest examples of the plight of “old marble eyes” comes from Lac Vieux Desert in Vilas County.

State and tribal fisheries biologists have been following a years-long walleye decline in the large lake that straddles the Wisconsin-Michigan border.

Last spring, biologists from the Great Lakes Indian Fish and Wildlife Commission (GLIFWC) estimated the lake’s walleye abundance.

Adult walleyes were captured by electro-shocking, marked with a fin clip and released.

A short time later, the lake was electrofished again. An estimate of the walleye population was calculated based on the proportion of marked fish caught during the second outing.

The work found the abundance of adult walleye hit a 26-year low of just over 2,000 fish in 2016. For perspective, the lake’s walleye population was estimated at a high of 13,000 fish in 1990.

More information was obtained last fall, when Great Lakes commission biologists and the Wisconsin Department of Natural Resources teamed up to study the lake’s age-0 walleye, or fish that were hatched in spring.

Crews collected the fall fingerlings by electrofishing the entire shoreline of Lac Vieux Desert.

The survey result was troubling: the effort found zero young-of-the-year walleye.

In the late 1980s and early 1990s, the relative abundance of age-0 walleye was about 30 per mile of shoreline. And it swelled to more than 80 walleye per mile of shoreline by the mid-to-late 1990s, according to the Great Lakes Indian Fish and Wildlife Commission.

It’s not unusual for a species to have poor year classes. But to sustain itself, a healthy population must have years of good recruitment every so often.

In the case of Lac Vieux Desert, the 2016 results are not an anomoly. Extremely low or no recruitment of walleyes has been seen for the last 10 years.

With such a low influx of new fish, the population of adult walleye in Lac Vieux Desert has fallen from 2.1 fish per acre in 2012 to 0.54 in 2016, according to DNR surveys.

Biologists don't have a definitive explanation for the lack of recruitment.

But the “switch” of northern lakes from walleye-dominated to bass-dominated has been the subject of much discussion and debate in recent years.

A study published last year found natural walleye lakes could be a rarity in Wisconsin by mid-century. The culprit? Climate change.

The work found increasing water temperatures were linked to declining walleye populations and rising largemouth bass populations.

By 2040, just 4% of Wisconsin lakes might be able to support naturally sustained walleye populations, down from 60% today. And 89% of lakes could have conditions suited to high-abundance largemouth bass populations, up from 60%.

The study was published in September in the scientific journal Global Change Biology; its lead author was Gretchen Hansen, now of the Minnesota DNR and formerly of the Wisconsin DNR.

A University of Wisconsin study planned to begin this year on a northern Wisconsin lake will assess the impact of panfish predation on walleyes.

Researchers will attempt to remove as many bluegills, crappies and other sunfish as possible and monitor walleye survival over the coming years.

The panfish will be transferred to a nearby lake.

While it’s clear other fish prey on young walleyes, this study will attempt to quantitate several factors related to predator abundance and walleye recruitment.

It’s not known, however, if it will produce a feasible strategy to help naturally-reproducing walleye populations recover in lakes across the region.

Could enough walleye predators be removed on enough lakes to make a significant difference?

On Lac Vieux Desert, a coordinated effort has begun to address two issues within human control: Harvest and stocking.

The Wisconsin DNR, Michigan DNR, the Lac Vieux Desert Band, Sokaogon (Mole Lake) Chippewa and the Great Lakes Indian Fish and Wildlife Commission have developed a draft plan with a goal to restore natural reproduction and increase the density of adult walleye to at least 2.5 fish per acre.

The plan would institute an 18-inch minimum size limit and three fish daily bag starting in 2018 and running through at least 2022 (anglers may currently keep five walleyes daily with a 15-inch minimum length limit).

The tribes also would agree to not spear or net walleyes from 2018 through 2022.

The lake also would receive about 64,500 extended growth walleye fingerlings (6 to 8 inches in length) each fall in even number years.

Public meetings to discuss the plan will be held April 4, from 7 to 9 p.m. in the library of the Land O'Lakes Elementary School, 6485 Town Hall Road, Land O' Lakes, and April 6 from 7 to 9 p.m. in the cafeteria of Phelps High School, 4451 Old School Road, Phelps.

The goal to restore the walleye population on Lac Vieux Desert is a lofty one.

But the example of the tribes and state agencies working together is excellent.

Only through self-restraint, selective harvest and continued research will our walleye populations have a chance to thrive into the future.