The local DNR began implanting survey captured muskies with PIT tags in 2007. Though it certainly does contribute, this method is relatively low intensity. Due to the limited availability of personnel, survey boats, and size of the waters managed, each flowage can only be surveyed once every 5-7 years. Add on top of this that some stretches simply do not survey well, and variability in spring flooding, and this method became viewed as increasingly limited. From 2007 to 2019, the following amounts of muskies were PIT tagged through survey capture: 146 Lake Wausau, 117 Mosinee Flowage, 151 Stevens Point Flowage, 569 Petenwell Flowage, 126 Castle Rock Flowage. This represents a grand total of 1,165 muskies PIT tagged by DNR personnel in the field. PIT tagging of stocked fingerlings began in 2010, but was not consistent and never reached 100% of stocked muskies. The years 2010, 2012-14, 2016, and 2018 received a total of 2,582 PIT tags. In 2012, 2 anglers were permitted to tag in the southern end of the area (Petenwell Flowage) and contributed 81 tags. This background provided the impetus for this project: to ensure all stocked musky fingerlings receive PIT tags, and to begin the process of training and permitting a limited number of anglers further upstream to implant PIT tags in their caught muskies.
In 2019, 14 muskies were reported by anglers with a PIT and/or anchor tag. Two of these recaptures were known age muskies. Two were tagged as fingerlings stocked by WILMA in Lake DuBay in 2016, and caught 1 dam downstream in the Stevens Point Flowage. One was tagged as a fingerling stocked by WILMA in the Stevens Point Flowage in 2013, and caught 2 dams downstream in Biron Flowage. (It should be noted that there was one known age recapture in 2018, a 30” musky stocked in 2013 in Stevens Point Flowage and caught in Biron Flowage. Two fingerlings were recaptured in Stevens Point Flowage in 2015 after being stocked there in 2014. This is the entirety of known age recaptures.) Of the 12 remaining recaptured muskies, all were tagged as adults, and only 2 migrated downstream. So far this indicates a bit of a split in the population—66.67% of muskies tagged as fingerlings have moved downstream so far, whereas only 16.67% of adult tagged muskies have been recaptured downstream in this project. Adult muskies recaptured in Mosinee flowage were at large for 9-11 years in the same flowage. We are definitely tracking this closely. This begs the question: is this because stocked fish tend to move, and native spawned fish do not, or is it simply that smaller fish tend to move downstream more than adult fish? Does this movement correlate to high/low water events? Continued PIT tagging of fingerlings in conjunction with time for those fish to recruit into sizes sampled by angling will allow us to gain more data in the future to see if this trend continues, or is a fluke due to small sample size.
In 2019, the DNR stocked Lake Wausau with 925 musky fingerlings. The following flowages were stocked from private sources: Lake DuBay 400 fingerlings (200 from WAMI), Stevens Point Flowage 741 fingerlings, Petenwell Flowage 800 fingerlings, Lemonweir River (Castle Rock Flowage tributary) 150 fingerlings, and Yellow River (Castle Rock Flowage tributary) 150 fingerlings. All stocked fingerlings received PIT tags for the first time ever. An all-time total of 6,913 muskies have been PIT tagged in the Central Wisconsin portion of the Wisconsin River through all methods. 3,166 (45.8%) of that total are from this last year’s stocking alone. That is an impressive result that speaks to the buy-in of the area musky organizations and the new approach from the DNR. WAMI provided a total of 600 of those PIT tags. Among our members, Jeff Micholic and Shane Woller were able to volunteer to go to the Art Ohlmke Hatchery and tag the DNR raised fingerlings that were stocked into Lake Wausau. This experience has raised their competency with the DNR and pushed them to the forefront in the tagging permit process.
The 2019 spring survey occurred during April on the Mosinee Flowage (716 acres). High water had significant negative impacts on the survey. Flooding was severe to the point that DNR personnel stopped taking volunteers in the survey boat due to liability concerns. The boat was being launched in the parking lot. It was difficult to find locations with current breaks to set nets (too much current causes the nets to twist, as well as to catch debris such as deadfall trees and then be torn or broken free). Flow peaked at over 46,000 cfs; for comparison, the average April peak for the preceding 4 years was only 18,425 cfs! Despite this, 4 members were able to spend time in the survey boat, where they handled and scanned muskies. Three of the 4 handled recaptured muskies. Jeff Micholic, Darrell Fritz, Shane Woller and Tristan Marten were the volunteers. Two additional community volunteers assisted in the survey.
49 muskies captured, 6 were recaptures (12.24%) including multiple tagged 10 years ago. This is a wonderful result, given the unusual level of difficulty in this survey.
A few noteworthy fish:
-Anchor tag #00217: first captured and tagged in 2011 at 44”; recaptured in the 2019 survey at 47”.
-Anchor tag #00092: first captured and tagged in 2010 at 46.9”; recaptured in the 2019 survey at 48” (this fish was also reported caught by an angler in 2018).
-Anchor tag #00171: first captured and tagged in 2009 at 39.5” (male); recaptured in the 2019 survey at 43.5”. This fish was also reported angler caught in 2013 and 2017, as well as in a 2011 survey.
Shane has been permitted to tag angler caught fish in 2020 and so far has tagged about a half dozen on Lake Wausau. Here’s the basic process, illustrated.
A musky is caught during league. The angler calls or texts Shane. The musky is left in a net over the side until he arrives. Shane places a cradle on top of his bumpboard to help restrain the fish during the process. Shane then scans the musky to detect if it already has a PIT tag. Finding no tag, Shane implants one. The applicator is basically a syringe that shoots a tag the size of a grain of rice into the fish. The tag is implanted in the fish’s back. The fish is then released using the cradle. The tag number and fish’s length are reported to the DNR.
Another important aspect of this project has been assessing the local musky population through the use of historic catch data. So far, all Muskies Inc. Lunge Log data, the past two years of Bill’s Musky Club, and the past four years of Wisconsin League of Musky Anglers (WILMA) have been analyzed. This data has then been broken down into population size distribution estimates (PSD-36, PSD-45, PSD-48 for percentage of fish over 36, 45, and 48” respectively) and relative abundance estimates, by county, and by decade. The decision to split by county was largely because the Lunge Log offers entries divided by county for the same waterbody. For example, Lake DuBay lies in both Marathon and Portage counties; furthermore fish can be registered as Wisconsin River and technically that is also correct as Lake DuBay is an impoundment of the river. It seems to be the most convenient way to smooth the data out. The following charts were generated by DNR biologist Tim Parks.
Some noteworthy findings from this baseline data are:
-PSD-36 is relatively consistent and stable in our area, even across multiple decades.
-PSD-45 has generally shown upward trends over the decades; the largest exception being Wood County which has shown a significant decline (16% to 4%) from the 1990s to the 2010s. It should further be noted that the 2000s experienced a downward slump for across counties.
-PSD-48 has generally increased across the counties over the decades. Again, Wood County is the notable exception to this trend.
-For 2019 data, we also compared the average size reported by the Lunge Log, WILMA, and Wausau Musky League. These averages were 38.68” (108 fish), 39.67” (78 fish), and 38.08” (30 fish), showing broad consistency in average length of caught fish in our area. This also lines up well with DNR survey data.
Due to COVID-19, much of the 2020 plans have been upset. No stocking (hence no tagging of stocked fingerlings) will occur. The 2020 spring survey on Castle Rock Flowage was cancelled. We however do have an angler permitted to tag, and are still obtaining catch records for baseline data. The piece of data we will be trying to get a better handle on from now on is catch/angler effort (measured in hours). We have the stats from our tournament, and both musky leagues we work with have a registration system we can use to get a reasonably accurate estimate. In 2021 we hope to provide PIT tags for all muskies stocked in our area. We are optimistic that much useful data lies ahead, and an even better fishery in years to come!