Background
To understand how Walleye are affected by other fishes, we will be conducting a multi-year experiment on McDermott Lake in northern Wisconsin. We will be removing as many bass and sunfish from this lake as possible beginning in summer 2018. These fishes are thought to be potential competitors and/or predators of Walleye, so by removing them we will see if this opens a window for the Walleye population to recover. Although removals began in 2018, we started the project with a lake selection process in 2016-2017 and began collecting baseline data in 2017.
Scroll down to learn more about the lake selection process, 2017 & 2018 sampling, and see photos from the field.
Scroll down to learn more about the lake selection process, 2017 & 2018 sampling, and see photos from the field.
How did we pick the lakes?
During 2016-2017, we gathered public and management input, surveys of fish populations, and removal cost assessments to determine the lake that would be best for this experiment. Through this process, we found that McDermott lake was the best candidate for the removal of bass and sunfish. McDermott Lake is a small (~100 acre) lake in Iron County, WI. Historically, McDermott Lake has had a self-sustaining Walleye population, but in recent years has experienced declining natural recruitment. Additionally, McDermott Lake has a rising population of bass and sunfishes. Given the public support and fish community characteristics, this lake was selected as the experimental lake. We will also be monitoring a nearby lake, Sandy Beach Lake, with similar characteristics as a reference. We will not be removing any fish or making any changes to Sandy Beach Lake, but will take measurements to make comparisons between the experimental lake and the reference lake.
More information on the lake selection process can be found here.
More information on the lake selection process can be found here.
FieldWork
In 2017, we sampled McDermott Lake and Sandy Beach Lake to collect baseline information prior to removing fish. We gathered information on the Walleye population and the complete fish community through multiple sampling techniques, including electrofishing, fyke nets, and clover traps. We also collected information on other parts of the lake, such as the food for fish (macroinvertebrates, zooplankton, crayfish), plants, water chemistry, and temperature. In 2018, we continued these monitoring efforts and also began removing fishes from the lake.
Detailed descriptions of days in the field with additional photos can be found here and here.
2017 Preliminary Results
We estimated that there were ~45 adult Walleye and ~315 adult Largemouth Bass present in McDermott Lake, but we did not find any evidence of natural Walleye recruitment. The fish community of McDermott Lake was dominated by small sunfishes, particularly Bluegill and Pumpkinseed.
2018 Preliminary Results
We estimated that there were ~40 adult Walleye and ~800 adult Largemouth Bass in McDermott Lake. Similarly to 2017, we did not find any evidence of natural Walleye recruitment. In total, we removed ~85,000 fish (~2000 lbs) from McDermott Lake.
Detailed descriptions of days in the field with additional photos can be found here and here.
2017 Preliminary Results
We estimated that there were ~45 adult Walleye and ~315 adult Largemouth Bass present in McDermott Lake, but we did not find any evidence of natural Walleye recruitment. The fish community of McDermott Lake was dominated by small sunfishes, particularly Bluegill and Pumpkinseed.
2018 Preliminary Results
We estimated that there were ~40 adult Walleye and ~800 adult Largemouth Bass in McDermott Lake. Similarly to 2017, we did not find any evidence of natural Walleye recruitment. In total, we removed ~85,000 fish (~2000 lbs) from McDermott Lake.
Daily fishes removed from McDermott Lake in 2018. In total, ~85,000 fish were removed.
*Feel free to contact Holly Embke ([email protected]) with any questions about the experiment.