The Minocqua/Kawaguesaga Lake Association meeting last weekend included a presentation from DNR fisheries manager John Kubisiak regarding fishery information found in DNR surveys. Lake association president Sally Murwin also presented information about Eurasian watermilfoil (EWM) that has been removed with a DASH (diver-assisted suction harvesting) unit and what would be treated in September. The lake association turned to diver-assisted suction harvesting when the DNR denied a permit for herbicide treatments for EWM in their lakes. Murwin said next summer the DASH unit would be harvesting on the lakes again twice more.
Murwin presented the group with a map showing locations where EWM had already been harvested. Those areas are circled in yellow on the map. The other areas, represented by red block with no circle around them, will be harvested on Sept. 11, weather permitting. To date, a total of 16,500 pounds of EWM have been removed from the areas already harvested. That weight is the wet weight, she said.
In the fisheries update, Kubisiak presented information related to game fish and panfish. He also updated the group on the walleyes in the chain.
He gave the group a comparison between a 2009 survey and a 2015 survey. He started with bass population estimates. The largemouth population, he said, is 9,700 over 8 inches. That, he said, is about 7.1 largemouth per acre of water. On Kawaguesaga that number was about 10.1 per acre. He considers both of those as "high density" lakes.
Smallmouth, he said, are abundant on Lake Tomahawk, but are more of a secondary species on Minocqua and Kawaguesaga. Size, he said, was comparable to the size of largemouth, with the largest being 19.4 inches on Minocqua. They were unable to handle enough fish to get a population estimate, but based on what they did see, he estimated there was about one half to three quarters of a fish per acre, making it a low density" species in the two lakes.
He then moved to muskies, which spawn later in the year than walleyes, he said. When the department wants to target muskies, they come back later with slightly different equipment. They did not do that in 2015. They also do not shock well, however, they did capture 122 muskies, with 86 being less than 20 inches. The biggest fish was 48.0 inches and 35 pounds. It was a large female who had not spawned yet.
Pike spawn about the same time as walleye, he said, and they net very well. He reported not seeing high numbers of pike on the chain, handling just 95 on the three lakes. In 2015, Kubisiak reported seeing a good deal of 22-30 inch fish, but not many smaller fish coming up. For a musky lake, he said, this is not necessarily a bad situation, as musky and northern pike do not occupy the same areas and tend to eat each other.
He also reported his team handled about 1,600 yellow perch and 1,600 crappie. While perch were not measured, they did measure some crappie. They found good numbers from 7 up to 10 inches when measuring 300 fish. As far as bluegill, he said, they are by far the most abundant fish. The team handled almost 7,500 bluegills, with good numbers out to about 8 inches. This size structure, he said, is fairly decent.
A creel survey, he said, was done in 2009. It is a snapshot of angler effort, letting him know how many hours anglers were putting in, how many fish they were catching and how many they were harvesting. The fisheries department, he said, does nine or 10 creel surveys per year. The average is 33 hours per acre into creel surveys each year. On Lake Minocqua, however, the surveyors spent approximately 56 hours per acre of water in the lake. Creel surveys are nine month surveys.
"Three quarters of what people were catching in 2009 on both lakes was smallmouth bass and largemouth bass, and lower numbers of northern pike and walleye," he said. "If we look at the harvest, they were actually harvesting walleye and northern pike with lower numbers of bass."
Most anglers, he said, do not keep many bass. It was estimated anglers caught 43,569 game fish and only harvested about 1,600. Approximately half of the walleyes and pike caught were harvested, but very few bass were harvested. More fish, on average were harvested on Kawaguesaga versus Minocqua, he said. For panfish, 128,184 were reportedly caught with 49,607 harvested, 16 times as many as game fish. There are a lot more pan fish, he said, in our lakes.
"That's kind of their job is to take the brunt of the harvest," he said. "That's what they do out there. They are eaten by everything else."
His discussion eventually turned to walleye population estimates, starting with the 2009 walleye survey. He talked about netting and electroshocking surveys. Estimated walleye populations ran from 1.3 to 3.3 per acre in his estimates on all three lakes. Those numbers, he said, were fairly reasonable. They were only about half of what was seen in the 1990s, but the populations were still decent. About 41 percent of the population, though, was over 20 inches. Typically that number would be only 5-10 percent over 20. High numbers of big fish drove the population where normally 11-13 inch young males normally account for the majority of a walleye population. While populations were still good, size structure set off some red flags for Kubisiak and his team. It pointed to recruitment problems for walleye.
While walleye recruitment is typically up and down, it became obvious this was not the typical cyclical nature of things. In the 1990s, while recruitment was not as high as it could have been, there was still enough natural reproduction and recruitment to sustain the fishery. In the 2000s, he said, that started to change. Previously, Lake Tomahawk had been stocked with small walleye fingerlings. In 2009, Kubisiak requested extended growth walleye to be stocked in the fall of 2010. Because not many were being produced at the time, he did not receive any to stock. Large fingerlings are much more expensive to produce. He was able to receive large fingerlings in 2012, however. He also received large fingerlings to stock on Minocqua and Kawaguesaga in 2013. Since stocking of large fingerlings began, Kubisiak has seen fairly strong year classes due to stocked fish.
"While we see good results from stocking, natural reproduction has been minimal at best," he said.
In the 2009 survey, there were 3.4 adult walleye per acre in Kawaguesaga and 2.0 per acre on Minocqua. By 2015, those numbers fell to 1.3 and 1.0 respectively. There were still good numbers of big fish, but there was a gap in the middle, with good numbers again in the 12-13 inch range, which were the fish stocked as large fingerlings.
There were questions regarding the relationship between bass and walleye from several people.
"We've seen this trend across the north where we've seen - not just on this chain, but on other lakes - we've seen walleye populations decline and we've seen bass really come on," Kubisiak said. "So the logical assumption is the walleyes are making the bass go away or the walleye are keeping the bass in check and when they decline the bass take off. We've been looking at that and not finding a lot of hard evidence that bass are actually causing the walleye to decline as far as predation and that, but certainly they all eat each other, so there's going to be some impacts. If walleyes are dominant, we know they keep bass in check. We've seen that. We haven't seen real strong evidence that bass keep walleye in check. But they do affect each other in some way."
He said changes in the fish community may be a factor as it is difficult for walleye to push back once they lose dominance in a fishery.
Kubisiak also addressed uses of chemicals and manicured shorelines, saying there may be some loss of habitat, but the DNR does not have any evidence of impacts of fish in particular. He then spoke about different regulations that have been put in place.
In the past, there was a 14-inch limit on bass, which has been removed. Kubisiak said he would be interested in the 2020 creel survey to see if more bass are being harvested. The DNR, he said, does not have a great deal of information on "no size limit" lakes, so those results could be interesting. For five years, there is a zero-bag-limit placed on the Minocqua chain for five years, which will come off for the 2020 season. For five years following that, he said, there will be a reduced bag limit of two fish over 18 inches. From there the hope is to return to a three-fish limit with a minimum size of 18 inches, but that will depend on the findings at that time.
He said they are seeing some initial positive signs from the stocked fish, but he was hoping to see more natural reproduction now that walleye populations of smaller sizes were doing better. Surveys and stocking will be ongoing on the chain and Kubisiak is hoping, at some point, Mother Nature will take over and natural reproduction of walleyes will resume.
Beckie Gaskill may be reached via email at firstname.lastname@example.org.
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