URBANA, Ill. — If you've had problems catching that trophy muskie of a lifetime, it may not be your fault.
Scientists at the University of Illinois say they have discovered some of the reasons why muskies are among the most elusive game fish swimming in freshwater.
Their research, published in the Jan. 27 edition of the North American Journal of Fisheries Management, shows that many muskies spend most of their time in out-of-the way places and are most often not in the mood to chase prey.
Instead, they wait for the prey to come to them. And that’s why they are called the “fish of 10,000 casts,” because you have to get just the right lure in just the right place at just the right time in front of just the right fish.
“Our results clearly show capturing (catching) muskies is not random. There are behavioral traits that predispose these fish to capture,” said Cory Suski, professor in the Department of Natural Resources and Environmental Sciences at the University of Illinois and a co-author of the study.
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Suski and graduate student John Bieber evaluated behavioral traits — activity, aggression, boldness and exploration — for 68 young muskies in laboratory tanks before transferring the fish to an outdoor pond. Each fish was microchipped, like a dog, so researchers could identify individuals and their traits.
Then the research really got interesting. The two scientists went fishing every day for five weeks to try to catch their study muskies. The hatchery fish were only about 14 inches long at the time, but, even in small ponds, mostly avoided being caught.
“After 35 days throwing our whole arsenal at them, every combination of time of day, lure and casting style, we can verify muskies are indeed the fish of 10,000 casts. We only caught seven fish. In addition, we saw that catch rates decline very, very rapidly after the first several days,” Bieber said. “It was a long month.”
None of the fish were caught twice. Bieber says that pattern lines up with muskies’ overall feeding strategy.
“They're very tough, sit-and-wait predators, which means they’ll just camp out under a log or at the bottom of the river until something comes right by,” he said. “Then they’ll burst out to take the prey.”
Not only are many muskies often not in the mood to chase lures, but researchers say they can “learn” to avoid anglers.
“We have anecdotal evidence that these fish seem to learn when anglers are around and actively avoid lures,” Suski noted. “And then there's the historical context. Years ago, people would harvest muskies. If they were taking vulnerable fish out of the population, then you just have hard-to-catch fish left today."
That’s why serious muskie anglers target their fishing locations carefully.
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“If you're an angler going around the lake, just casting randomly won't necessarily mean you’ll catch a muskie,” Bieber noted. “You have to get your lure perfectly in the face of a muskie of the appropriate behavior type (one poised to attack) to be able to initiate a strike.”
While anglers may be glad to learn it’s not their fault muskies are so hard to catch, the research has deeper implications for muskie conservation.
There are probably many muskies that are predisposed to never chase lures, Suski noted.
“That's what the data would lead us to believe,” he told the News Tribune.
Since fish behavior can be passed from one generation to another, anglers have a vested interest in keeping catchable fish — those predisposed to chase lures at least now and then — in the gene pool to keep breeding.
That makes catch-and-release fishing, which is already the standard for most muskie anglers, even more important. Even then, anglers should “be really careful with the fish you catch, minimize the handling, and release them as quickly as possible,” Suski said, and also minimize angling during the warmest water periods, when muskies could become stressed.
The study, “Capture is Predicted by Behavior and Size, Not Metabolism, in Muskellunge (Esox Masquinongy),” was funded with help from the Illinois Department of Natural Resources, the U.S. Fish and Wildlife Service, and the USDA National Institute of Food and Agriculture.
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