DNR Walleye Population Survey 2009

By Craig Zarley

Squash Lake’s walleye population is relatively dense and self-sustaining. That’s the conclusion from DNR’s spring walleye population survey. DNR fisheries biologists placed 8 nets from April 17-21, capturing 306 male walleyes and 93 females, according to Oneida County DNR fisheries biologist John Kubisiak. The DNR clipped fins of each of the captured walleyes and then returned to the lake April 25 for a follow up survey in which they shocked the entire shoreline and counted stunned fish.

During the shock phase of the population survey, Kubisiak said 96 male walleyes with unclipped fins were counted and 98 with clipped fins, indicating the latter group were counted the week before. Eight females were counted during the shock phase, 4 of which had clipped fins. Based on the combined results, Kubisiak estimates there are about 809 adult walleyes in the lake, or about two per acre. Because of the high ratio of recaptured fish in the shock phase of the population survey, he called the population estimates very accurate with only a +/- 7 percent margin of error.

Additionally, about 80 percent of the walleyes counted were longer than 15 inches with the bulk of the fish falling in the 16-inch to18-inch range. Kubisiak said based on the size of the walleyes counted, there is a chance the DNR will change the lake walleye regulations from three walleyes per day, only one of which can be greater than 14 inches to three per day with a minimum length of 15 inches.

“That’s a pretty solid population,” he said. “The walleyes are doing fine on their own.”

As a result, Kubisiak said there would be little if any benefit to stock the lake with walleyes and that the DNR would not grant a stocking permit. He said one goal of a stocking program is to bring the walleye population in a lake up to about 2 walleyes per acre, the level that already exists in Squash Lake. And he cautioned that there are potential downsides to stocking the lake with walleyes.

By bringing in fish bred in another lake, those fish would interbreed with native Squash Lake walleyes and alter the genetic makeup of their offspring. There is a risk that those genetically altered fish may not be able to adapt as well to Squash Lake conditions and thus may not be able to sustain a healthy population in the future. He also noted that when stocked fish are dumped into a lake, there is a slight chance invasive plant or fish species could be introduced.

“Once you go down that road [stocking walleyes], you can’t go back,” he said.

Kubisiak noted that based on a population of about 800 walleyes, 35 percent or 280 fish can be harvested each year without adversely affecting the population.

He suggested that one avenue for increasing walleye populations could be to keep fewer fish. He explained that since the practice of catch-and-release for Muskies took hold in recent years, the DNR has seen a dramatic increase in Musky population in county lakes. But fishermen tend to keep most walleyes they catch and he doesn’t expect catch-and-release walleye fishing to catch on as it has for Muskies.

With stocking fish not a viable option, perhaps the best strategy for boosting Squash Lake walleye numbers is to keep a few and release the rest.