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Inside the 2025-2026 Fox Lake Fish Survey

4 hours ago
3 min read

Ever wonder how fisheries biologists figure out what's swimming in your favorite lake? Wisconsin DNR Fisheries Biologist Mark Baldock recently walked through the 2025-2026 Fox Lake Comprehensive Survey, and the video is worth your time whether you fish Fox Lake every weekend or just like a good fish story backed by real data.



Short on time? The first part of the video covers how the survey is done. If you just want the results, skip ahead to about the 28-minute mark, where the presentation moves from process and science to the study findings.


"We set the nets. We catch the fish. It's what we do."


That's how Mark sums up the work, but there's a lot of science packed into that sentence. The presentation follows the survey through the seasons:

  • Spring netting begins right after ice-out, with nets set along points and shorelines leading to marshy bays for northern pike, then moved to rocky and gravel shorelines and islands for walleye.

  • Spring electrofishing includes recapture runs on walleye for population estimates, plus 2.0-mile transects to sample bass and panfish.

  • Musky netting happens a bit later, when water temps hit 50-55 degrees. Every musky is measured, sexed, and fin-clipped.

  • Fall electrofishing targets young walleye to see how well each year class is surviving.

The Tech: PIT Tags for Musky

My favorite part is the PIT (Passive Integrated Transponder) tagging. Each new musky gets a tiny tag, about the size of a grain of rice, that carries a unique code. A handheld reader "activates" the tag and pulls the code, and the tag can last the life of the fish.

That means biologists can track growth and survival of individual fish across years. This fall, the plan is to tag 200 large fingerlings before they're stocked. Because hatchery records give their exact age, the DNR can tell stocked fish from any natural reproduction and double-check earlier age estimates.

There's also a good segment on how fish are aged by counting the dark winter rings on fin rays and spines, much like tree rings.

The Preliminary Numbers (starts around 28:00)

Here's what the survey found so far, with percentiles compared to similar lakes:

Musky

  • 24 sampled in 2025 (average 41.6") and 17 in 2026 (average 39.6")

  • 7 recaptures in 2026

  • About 0.03 musky per acre

  • The largest was a 50.0-inch fish

Northern Pike

  • 1,739 sampled, in the 94th percentile

  • Average length of 25.0 inches

  • 1.75 pike per acre

Walleye

  • 1,376 sampled in spring netting, in the 79th percentile

  • Average length of 18.2 inches

  • 2.64 walleye per acre, with 79 recaptures in the electrofishing sample

Panfish

  • 3,001 black crappie (75th percentile), averaging 4.9 inches

  • 1,563 yellow perch (79th percentile), averaging 6.6 inches

  • 308 bluegill (52nd percentile), averaging 6.3 inches

Largemouth Bass

  • 171 sampled over 10 miles (49th percentile), averaging 15.1 inches

The standout is northern pike, which rank in the 94th percentile. Walleye, perch, and crappie all sit comfortably above the middle of the pack too.

What Happens Next

The work isn't done yet. Mark and his crew still need to finish fall electrofishing for walleye recruitment and survival data, complete aging of all the structures to estimate growth and mortality, and enter everything into the statewide database. Then comes a formal report with management recommendations, which goes through several levels of review before being posted on the DNR website.

Two things to watch for:

  • A panfish 10-bag limit regulation change proposal is moving through the approval process. The hope is to bring it as a question to the 2027 Spring Hearings, with an application date of April 1, 2028.

  • The next comprehensive survey is planned for 2032.

Why Watch?

Mark makes the science approachable, and the photos alone make it fun, from big muskies in the net to a little guy proudly holding a fishing pole at the end. If you care about the future of Fox Lake, this is a great look at how the data behind our fisheries gets collected.


 
 
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