January 13, 2022 at 11:53 a.m.
DNR, Walleyes for Tomorrow discuss use of Walleye Wagon for Minocqua Chain
DNR, Walleyes for Tomorrow discuss use of Walleye Wagon for Minocqua Chain
Recently, Walleyes for Tomorrow approached the DNR about using a Walleye Wagon on the chain to stock up to 4 million fry to see if this could spur numbers of walleye in the system to a point where they would once again naturally reproduce.
A Walleye Wagon is basically a portable fish hatchery. The wagon uses fish eggs and milt from fish in the lake into which fry will eventually be released. A standard wagon contains 12 jars which will each hold 300,000-350,000 eggs. This allows the Walleye Wagon to produce approximately 4 million fry which can then be stocked back into the lake.
DNR fisheries biologist Zach Woiak said during the past few months, he was looking into other lakes where Walleye Wagons had been used. In order to be successful, he said, natural conditions must allow walleye fry to survive for a Walleye Wagon to be successful. Some of the best candidates, he said, are those where natural fry are already surviving. His rationale for this was that if natural fry are not surviving, stocked fry would have a slim chance as well.
While poor existing natural reproduction, or lack thereof, has usually meant poor Walleye Wagon success, he said, there have been cases where use of a Walleye Wagon has supplemented natural reproduction during bad years. Stocked fish from a Walleye Wagon can make up a sizable percentage of a year class, but overall contribute to a minimal number of fish. Use of this stocking method rarely produces a year class of five young of year fish per mile or higher.
Mike Arrowwood from Walleyes for Tomorrow, however, said most of the lakes on which the group currently uses a Walleye Wagon do not have good natural reproduction. He used the examples of Lake Geneva, Pewaukee Lake, Shawano Lake and Big Green Lake. The Walleye Wagons, he said, have been able to produce enough viable fry in those systems to produce a good year class every year. On Big Green Lake, he said, they now have 15 year classes on that lake. At 7,000 acres, Walleyes for Tomorrow had been stocking 4 million fry each year, but then bumped the numbers up to 7-9 million fry. This proved to make a significant difference, with a good year class of stocked fish every year since.
"It all boils down to the number of fry you introduce into that lake." Overstocking, he said, would be just as bad as under stocking due to the available forage in a lake. If so many fish were stocked as to cause natural fry to starve to death, it would be just as bad as not stocking at all. Four-million fry, he said, would be what would be needed for a waterbody the size of Lakes Minocqua and Kawaguesaga. That could reasonably be expected from a Walleye Wagon, should the DNR allow its use on the chain. That would be the production goal for the Wagon, said Gregg Walker from Walleyes for Tomorrow Headwaters Chapter.
Woiak said the benchmarks for success would look at age-0 fish per mile or shoreline and a second number of age-1 fish per mile. For the Minocqua Chain, the hope was to see at least five age-0 fish per mile or shoreline and two age-1 fish per mile in the second year.
"This is an experiment," Walker said. "Let's see what we get on our return. You guys always put that out there because, in my opinion, you're setting us up to fail. Well, we're not going to bite." With current fry at almost nothing, he said, once the four-million fry from the walleye wagon could be put into the chain for a series of years, then they could look to evaluate the results. With the sex ratio so far out of wack, he said, something needed to be done in the way of stocking that was more than the DNR was currently doing. If that ratio could then be put back to a more normal level and there was still no natural reproduction, then it would follow that some environmental factor was likely affecting the survival of the fry themselves. He said using the Walleye Wagon would be an experiment and, at this time, was not looking to hang a number on success or failure.
Minocqua area guide and Walleyes for Tomorrow member Kurt Justice asked if there were any other methods available to determine how many fish were present. With only using fall electrofishing, he said, and the window was missed, it could look as though the Walleye Wagon stocking was failing, when in reality, that was not the case. DNR fisheries biologist John Kubisiak said he was not aware of any other method that could be used. He said, in the case of Lake Tomahawk, in years where fingerlings were stocked, they were showing up again in the next shocking season. With stocking in alternate years, he said, if the year following stocking results were 10-15 fish per mile and the next year, with no stocking, that number was almost zero. For that reason he felt the electrofishing method worked well.
Walker asked what would change with DNR stocking. Kubisiak said stocking of large fingerlings could conceivably happen in the same year as stocking of fry, as they would come up in surveys as age-0 and age-1 fish.
Arrowood asked why fingerling stocking could not be stopped while fry stocking was going on. He said research quoted in the walleye/ sauger culture manual showed there has never been a walleye population restored by virtue of pond-raised stocked walleyes.
Both Walker and Kubisiak felt large fingerling stocking should still continue. Adult densities were improving with those stocked fingerlings, Kubisiak said, and he did not want to see a backslide in those numbers by not stocking those larger fingerlings.
Walleyes for Tomorrow would cover the cost of some of the genetic testing for sampling. The cost would come in at approximately $20 per fish for 50 fry to send samples to UWSP Molecular Conservation Genetics Lab. Those fry would be genetically sampled before stocking. Genetic samples would also be taken from up to 50 age-0 walleye regardless of whether those fry were specifically stocked in the lake. Those samples would be taken during annual fall electrofishing surveys already done by the DNR.
Arrowood called for using the hatchery for at least four years. A multi-year survey, he said, was a more valid survey than just a "one and done" philosophy. Walker said there was no discussion about doing this level of stocking for a four-year term and would need to talk to the board before agreeing to a multi-year stocking effort. The group had volunteers in place for this year, he said, but there was no plan past that. Justice said he did not want to see a one-year effort as the plan and that multiple year efforts may bring results in year two or three, for instance, that was different than the first year. Kubisiak added, if Walleyes for Tomorrow agreed on a several-year effort but felt results did not warrant that expense and expenditure of resources, they would not be held to that.
Walker said extending the Walleye Wagon use would extend the study beyond the 2025 timeline of the 10-year study. He felt this would necessitate an entirely new discussion among Walleyes for Tomorrow board members.
Arrowood said running the Walleye Wagon was a 40-day effort and took a good amount of volunteer time and resources. He would come to the Minocqua Chain to conduct training for those who would be working on the Walleye Wagon as well as to facilitate needed permitting.
Fry would be distributed in different areas of the lake using boats, regardless of where the hatchery would be located. One of the thoughts was to have the hatchery at Torpy Park in Minocqua, but other locations could be considered that may have less runoff and, therefore, better water quality in the spring of the year. In order to get a permit from DATCP, the group would need a firm location. This, too, would have to be discussed at a board meeting before moving forward.
When looking at where fry would be stocked, Kubisiak asked to keep fry stocking as far away from Lake Kawaguesaga so as to not confound a study currently going on there. However, as Walker pointed out, this would mean releasing 4 million fry into an 800 acre area, which would lead to cannibalization and other issues.
With some of the permitting requirements looming, Walleyes for Tomorrow would discuss the duration of the study, as well as placement of the Walleye Wagon. From there, the group would get in touch with the DNR to move forward with the plans.
Beckie Gaskill may be reached via email at [email protected].
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