Muskie study taps escapement issue

Springfield — Choosing which strain of muskie produces the biggest and healthiest fish in Illinois waters was not the only purpose of a 10-year study labeled “Project Green Gene.”

Along the way, researchers decided to analyze an ongoing concern of biologists and muskie anglers alike: the escapement of the toothy predator over lake dams when water flows.

The study indicates an estimated 20 percent of 3- to 5-year-old muskies in a body of water escape during high water discharge periods. Many of the fleeing muskies end up in small streams or creeks, which makes them prime targets for poaching or predation if timely rescue is not made.

Illini Muskie Alliance President Ray Thompson, who authored a summary of the “Green Gene” report late last month, said Illinois Natural History Survey biologist Matt Diana, who was part of the “Green Gene” research team, will continue looking into the escapement issue – as long as funding for the project is available.

“That particular concern is one that plagues many, if not most, of the [lakes and waters] throughout the muskie range,” Thompson explained. In his summary of the 71-page study report, Thompson noted the main goals of the project, along with a brief history of how muskie stocking began in Illinois.

In the late 1960s, natural muskie populations in the Illinois portions of Lake Michigan, the Fox River watershed and the Mississippi River watershed had been mostly eliminated by pollution, over-harvest and the destruction of spawning habitat, Thompson noted. Except for a few private lakes with stocked fish, muskies had disappeared from the state. A committee of the Chicagoland Muskie Hunters Chapter of Muskies, Inc. was formed in the early 1970s, and through private donations, the club purchased muskie fingerlings from a private hatchery in Wisconsin to begin a stocking effort.

As for “Green Gene,” the study’s objectives were broken down into four goals: evaluate the growth of different stocks of muskies, evaluate survival of the different stocks of muskies, determine the diet composition of muskies and summarizing information and develop guidelines for proper selection of muskie populations for stocking in Illinois waters.

“Our aim is to increase the trophy potential and maximize the effectiveness of the money spent stocking muskies in Illinois,” Dave Wahl, principal investigator of Project Green Gene, said. “We want to find out what strain of muskie performs best in the different regions of Illinois.”

One important finding of the study was that Minnesota’s Leech Lake strain of muskie, which is popular for its growth potential, isn’t well-suited to the warmer climate of Illinois. Researchers stocked three strains of muskie into three different lakes for five years, then monitored each lake’s muskie population for five years. The strains – the Leech Lake strain, a strain of muskie from Illinois’ stocking program called the “mutt strain” and a strain from Ohio – were stocked and studied in Pierce Lake, Sam Dale Lake and Mingo Lake. All three strains grew pretty similar, Diana said. However, the Leech Lake strain fish had a lower survival rate.  While the three distinct strains will not be stocked on an annual basis, it is believed IMA member clubs will continue to provide the Leech Lake strain for some specifically selected Illinois lakes on a periodic basis.

“Independent research by myself and another, along with private research from one of the IMA member clubs, indicate that a majority of the larger Illinois muskies captured – fish 50 inches or larger – have been Leech Lake strain fish,” Thompson said. “What is even more surprising is the fact that these Leech Lake strain fish have only been stocked, periodically, in four of the 12 Illinois lakes which have produced these larger fish.”

The project, a collaborative effort between DNR, the Central Illinois Chapter of Muskies Inc., and several other Illinois muskie clubs, does not recommend any changes in the state’s method of muskie management.

Thompson said the ultimate decisions on the management of muskies in Illinois is the responsibility of DNR, adding that DNR Fisheries head Debbie Bruce’s reaction “indicates that muskie stocking using the Illinois “mutt” strain will continue for the present time.”

DNR and INHS will continue to monitor existing populations of the three study lakes, Thompson said.

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