Minnesota Department of Natural Resources fisheries biologists on April 18 completed the first step in a research project that will provide information about the number of Mille Lacs Lake walleye hatched in the wild.
Biologists collected 160 quarts of walleye eggs from Mille Lacs Lake and fertilized them.
5-10 million fry will be released back into Mille Lacs Lake, the DNR said on its web page.
Unlike conventional stocking efforts, fry that hatch from captured eggs will be marked and released back into Mille Lacs. Normally, stocked fry come from eggs captured elsewhere.
This key difference is necessary to protect the genetic integrity of the Mille Lacs walleye population.
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Fisheries biologists will use data collected this fall to compare numbers of walleye born in the hatchery to those born in the wild.
Information collected will help the DNR assess wild fry production.
While there are currently enough spawning walleyes in the lake, DNR is collecting information for a worst-case scenario if a time comes when there are not enough walleye to spawn.
If natural production of walleye fry ever dropped to a level where stocking became necessary, information gathered in this study will help DNR determine an appropriate stocking rate.
An estimated 300 female walleye supplied eggs for the project.
The DNR expected the fry hatch in approximately 10-17 days from the time of fertilization, depending on water temperatures, hopefully matching the natural egg hatch on Mille Lacs.
The fry will be marked with oxytetracycline, a common antibiotic that places a mark on the fish's ear bone, in order to differentiate fish from those released and those produced in the lake by natural reproduction.
The marks also allow DNR to estimate critical parameters of the wild fish, including natural hatch rate and numbers of naturally reproduced fry, as DNR has done in several other Minnesota lakes including Leech, Vermillion, Ottertail, Winnibigoshish and Red.
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The hatched fry will be transported from the St. Paul hatchery and released back into Mille Lacs.
Young fish caught this fall by electrofishing and in assessment nets will be examined for marks, the DNR said.
