New tool helps id musky spawning locations - Muskie & Pike - Muskie & Pike

New tool helps identify musky spawning habitat

MADISON – Protecting spawning habitat is critical to Wisconsin’s musky populations and biologists now have a new, less expensive, less labor intensive way to identify where the elusive fish spawn.

Results from a two-year study that analyzed spawning habitat on 24 lakes in northern Wisconsin have been used to create a computer model that soon will help fisheries biologists identify where musky spawn on 500 more lakes throughout the state, says Paul Cunningham, Department of Natural Resources fisheries policy ecologist.

“Once we’ve identified the spawning grounds on each lake, we’ll be able to uncover which areas are in pristine condition and needing vigilant protection versus other areas that are in need of rehabilitation,” he says.

Researchers and volunteers used spotlights at night to locate spawning muskies as part of a study to help identify critical spawning habitat.
WDNR Photo
To build the model, research teams comprised of University of Michigan researchers, Musky Clubs Alliance of Wisconsin members, and Wisconsin DNR fish crews used handheld spotlights to search the entire shoreline of each lake for mating muskies. Each time a musky was seen, the location was marked and its position recorded using digital mapping software. The researchers then collected data about and described the ecological conditions they found at those spots. Researchers returned to the site the next day to verify that spawning occurred by searching for eggs on the bottom.

“We took the preferred spawning habitat characteristics, such as rushes, under-water vegetation, groundwater flow, woody habitat, and moderate slopes, and created a Geographic Information System (GIS) model that, when applied to other lakes in Wisconsin, can predict the most likely spawning habitat,” says Joe Nohner, the University of Michigan researcher who led the study.

“Before, there were no efficient ways to determine the locations where musky actually spawn in a lake,” says Nohner. “Using the GIS model, DNR will be able to quickly identify these locations without performing costly and time-intensive surveys on each lake.”

Using these data, fisheries staff will be able to concentrate their efforts on high-priority areas.

Previous research conducted by the University of Michigan and the DNR showed that lakes with self-sustaining musky populations are mostly surrounded by forest, whereas lakes that require stocking often have less natural shoreline and more human development.

“Stocking cannot fully offset losses in natural reproduction, and it’s very expensive,” explains Cunningham. “The most effective long-term approach for musky is to preserve natural reproduction by protecting spawning and nursery habitat – it’s our state’s largest fish hatchery!”

The 2007-2008 study that served as the foundation for this model was funded by the Musky Clubs Alliance of Wisconsin, University of Michigan and the DNR.

Visit the musky page of the DNR Web site for more information on musky management.

FOR MORE INFORMATION CONTACT: Paul Cunningham (608) 267-7502, Joe Nohner (402) 660-0282