Scientists removed 285,000 fish from Wisconsin lake; yellow perch rose 788%
Researchers conducted a four-year experiment at a Wisconsin lake to determine if removing competing fish species could help restore declining walleye populations. While the removal of over 285,000 centrarchids led to a massive 788% surge in yellow perch, it failed to trigger the expected natural recovery of walleye.
Why it matters
The study highlights the complexity of aquatic ecosystem management and suggests that simple population control methods may not be sufficient to reverse the decline of key game fish species.
Scientists removed about 285,000 warm-water fish from a Wisconsin lake over four years in an attempt to help its declining walleye population recover. The large-scale experiment reduced several fish species and was followed by a sharp rise in yellow perch. However, it did not restore natural walleye recruitment.According to Wiley online library, the experiment was carried out at McDermott Lake in Iron County, northern Wisconsin, between 2018 and 2021. The lake covers about 33 hectares. Around 285,100 fish, weighing about 3,190 kg in total were removed from the lake. The fish belonged to a group called centrarchids, which includes species such as bluegill, black crappie, largemouth bass, pumpkinseed and rock bass.Scientists were testing whether removing these fish could reduce competition and predation faced by young walleye. Walleye are an important game fish in north-central North America and support recreational and tribal fisheries.
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