A new study by a PH.D candidate says a type of 'hidden over harvest' from fishing plays a role in the decline of the prized walleye populations in Wisconsin. Holly Embke is a graduate student at UW-Madison's Center for Limnology and is the lead author of the study. Ken Krall spoke with Embke about the study and why in some areas, a new school of thought has emerged about declining walleye populations...
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A new study by a PH.D candidate says a type of 'hidden over harvest' from fishing plays a role in the decline of the prized walleye populations in Wisconsin.
Holly Embke is a graduate student at UW-Madison's Center for Limnology and is the lead author of the study. Embke says they studied the walleye populations from 1990-2017. They studied how much biomass, or fish by weight, was removed from populations versus how much was produced....
"...From that we found populations were 10 times more over-harvested than that were commonly thought of based on current management findings..."
She says if you use what she calls a 'production approach' versus bag limit approach, it produces a very different picture of declining populations. She says it gives a prospective on potential over harvesting of the game species....
"We found a lot of variability on a lake-to-lake basis. Meaning, one lake, potentially right next to another lake, had a really different production level compared to another lake. Some lakes could sustain much higher production levels than other lakes..."
Trout fishing is regulated on a steam by stream basis.
She says the lakes are warming, hurting cool-water loving fish like walleye. She says overall, walleye populations have declined by 35 percent. She says there's also been a loss of habitat and the increase of warm-water species. She says at the same time there's unchanging harvest levels.
Embke says the study will likely be published this week by the National Academy of Sciences.
