Muskie experts publish research and management needs

By on June 17, 2015
Queen, the 50-pound Great Lakes muskie, on the day it was trapped and tagged. It was later caught and stood as the state record for several years. (Credit: Michigan DNR)

 

Few fish hold the same allure for Midwestern anglers than the muskie, but the species isn’t thriving across its native range. Fisheries scientists have laid out their research and management priorities to help restore muskies where they’ve waned and protect them where they remain.

A gathering of muskie experts in 2013 concluded that identifying spawning habitat, restoring habitat and fish populations, and sorting out genetics  were the prime concerns for muskies and their fellow esox the northern pike.

Those priorities were made as official as these things can get with their publication in the journal Fisheries. An article authored by Derek Crane, a research associate with Lake Superior State University’s School of Biological Sciences, summarizes important advancements in muskie science and the status and future of muskie research and management.

“I think it’s heading in the right direction,” Crane said. “Researchers are involved, managers are involved and the stakeholders really care about the resource.”

There are places where that resource is thriving: Muskie populations are “phenomenal” in northern Wisconsin and Lake St. Clair, Crane said. But there are some places where they’re struggling to reproduce naturally, and others spots within their native range where they no longer exist in meaningful numbers. Western Lake Erie once supported a commercial muskie fishery, Crane said, but the few fish that remain there aren’t even enough to hold up a recreational fishery. Muskies have also disappeared from Ohio River tributaries in West Virginia, Kentucky and southern Ohio.

The decline is often blamed on habitat loss, so learning more about the environments where muskies are spawning and their eggs are hatching important area of recent research.

For example, a recent study out of northern Wisconsin recruited muskie anglers in the offseason to survey 28 lakes and spot spawning muskies.  Researchers analyzed the habitats in those locations, finding that the conventional wisdom for what makes up ideal spawning habitat didn’t always hold up.  They found muskies spawning over sand, and in some lakes saw muskies avoiding vegetation the species is thought to prefer.

Muskies spotted courting in a Wisconsin lake during a habitat study. (Credit: Joe Nohner)

Muskies spotted courting in a Wisconsin lake during a habitat study. (Credit: Joe Nohner)

They created a model from that work to help predict where muskies might be spawning in other Wisconsin lakes where the species hasn’t been surveyed so closely. Crane used the framework from that study to do similar work in the Niagara River. They now have a better idea of where fish are spawning in the upper river, which again brought some unexpected findings.

“It was really surprising that most of the spawning is occurring over filamentous algae, which generally isn’t what they spawn over,” Crane said. They also found incubating eggs that “seem to be surviving in there.”

Learning not just where muskies are spawning but where eggs are successfully hatching and larvae are surviving will be an important area of future study, Crane said.

“That’s a major question that still needs to be addressed,” he said. “Because if you get at that, then you can start focusing restoration efforts on certain habitats.”

Scientists have also made advancements in understanding muskie genetics. DNA work in Minnesota, for example, has taught the state more about which strains inhabit their lakes.

Some lakes there were once stocked with the smaller and slower-growing Shoepack strain, but that ended when the state switched to the more desireable Leech Lake-Mississippi strain. But in Baby and Man lakes, where Shoepack stocking stopped in the 1970, genetic studies showed that 9 percent of the lakes’ muskies still had Shoepack ancestry, according to a release from the Minnesota Department of Natural Resources. That’s enough to have an impact on the potential size of some muskies in the fishery there.

“This study could set the stage for future muskie management decisions on lakes with residual Shoepack ancestry,” said DNR fisheries supervisor Doug Schultz in the release. “A study using DNA adds a new level of certainty about the effects of past stocking. That helps as we take multiple factors into account when making management decisions aimed at improving opportunities for anglers.”

Those anglers could also play an important role in future muskie research. Fisheries research has relied on anglers in the past to return tags and other information on the fish they catch, including size and locations. But they could also contribute to DNA work. Crane said anglers could take small fin clips, dry them and submit them to scientists who could extract genetic information.

Muskie experts and anglers will get a chance to spend some time together at the 3rd International Muskellunge Symposium, which will also mark the 50th anniversary of Muskies, Inc.

“If we can continue putting efforts towards understanding some of this stuff, we’re going to be able to restore some of these populations that have been lost and conserve the ones we have,” Crane said.

Top image: A 50-pound Great Lakes muskie that was later caught and stood as the state record for several years. (Credit: Michigan DNR)

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