Raising tigers: How F&G uses tiger muskies in sport fish management

It might not be top of your mind during a day out on the lake, but lying just below your bobber or bow is a whole web of predators and prey that keep the fishery afloat, so to speak. 

For decades, Idaho Fish and Game’s fisheries staff has studied interactions between fish species and pulled biological levers to maintain healthy fish populations and provide a slew of quality opportunities for anglers. 

“We have a handful of tools we can use to help keep populations balanced,” Fish and Game’s Sportfish Coordinator Martin Koenig said.

A tool with teeth, and a hearty appetite

There are numerous mechanisms biologists use when a fishery’s balance gets disrupted, and there is one "secret" weapon — a silent killer — fish managers strategically deploy to thin out overabundant species and provide a chance for a trophy in the process. Behold, the tiger muskie.

Tiger muskies are a cross between northern pike and muskellunge (or muskies). Like both species, they can grow very large, over 40 inches, and live up to 15 to 20 years. Their bodies are long, with vertical stripes like a green and white, well…tiger. And coming to a point is an alligator-like head that contains dozens of razor-sharp teeth. 

Anyone who’s ever experienced the rare joy of hooking a tiger muskie only to have it shear right through their monofilament line knows darn well how sharp their teeth are. 

In the beginning…

Every stocked fish species has a birthplace, and for tiger muskie, that place of birth is outside state lines. Wyoming, in fact.

“Rearing tiger muskie is a very specialized process compared to others raised for stocking purposes,” said Chris Jeszke, the manager at Idaho’s Hagerman State Fish Hatchery. 

Rearing tiger muskie can be a challenging, tedious process, Jeszke said. To make a tiger muskie, you need a male northern pike and a female muskellunge (muskie). Female muskellunge are not always readily available, therefore making spawning a challenge.

Once the eggs are fertilized, they are reared in Wyoming for several months until they hatch. Once they’ve reached roughly 3 inches in length, they are trucked to Idaho’s Hagerman State Fish Hatchery where they continue growing.

“They’re at Hagerman for about a year,” Jeszke said. “During that time, they get up to about 10 inches long. Then they’re ready for the stocking truck.”

Stocking tigers

Normally when an angler sees a Fish and Game stocking truck back up to their local pond or lake, they can anticipate some couple thousand rainbow trout, or maybe even some panfish to throw their lines at. But stocking tiger muskie isn’t always about the catch.

Starting in the late 1980s, Fish and Game fish biologists began looking at new ways to control unwanted or overabundant fish species in a select few alpine lakes around the state. Species like brook trout, pikeminnow, carp and sucker can dominate a fishery without a predator base to keep their numbers in check.

Those same species can also out-compete native fish like cutthroat trout, or reduce numbers of popular game fish like bass and bluegill.

The question fisheries managers were circling: Can you introduce a biological element to control unwanted or overabundant species? One possible solution considered by biologists, according to Koenig, was the tiger muskie.

“Tiger muskie are just as picky with an angler’s lure as they are with other fish species after they’re mature,” Koenig said. “Generally they’ll avoid fish with spines, such as bluegill, perch or bass, and prey on rounder, softer-bodied species, like brook trout and suckers.”

Hitman of the high lakes

Tiger muskie are no strangers to Idaho’s waters. They have made home in the state’s waters for roughly 35 years, and provide not only a challenging trophy fishing opportunity (if you’re lucky enough to hook one) but can assist in keeping alpine lake species, especially prolific species like brook trout, in check.

In the mid-2000s, biologists experimented with tiger muskie to reduce brook trout populations in a handful of high alpine lakes. Brook trout can be popular with anglers because they are often plentiful and easy to catch, but they have a downside. They can overpopulate and become stunted, so you get a lake filled with 4 to 6-inch trout, and they can also compete with native cutthroats and interbreed with bull trout. 

Rather than treat a lake with chemicals to wipe the slate clean and start over, tiger muskie can be a biological strong arm to keep the system in check if the conditions are right, setting the stage for species like cutthroat or rainbow trout to be reintroduced, or boosted. 

Using tiger muskie to reduce and, sometimes, exterminate a population of overabundant species is a biological lever that rarely gets pulled, Koenig notes, and is far from a perfect solution. The project showed some definite success, but it wasn’t consistent. 

“While it works great in some lakes, it doesn’t always take,” Koenig said. “We saw that happen in 2007 at Merriam Lake when we introduced tiger muskie to predate on brook trout.”

Located just south of Mount Borah, Merriam Lake is one of the highest alpine lakes stocked by Fish and Game, at an elevation of nearly 9,600 feet. Fish and Game fish managers introduced 107 tiger muskie in an effort to remove the brook trout population. Koenig thinks a combination of extremely cold water temperatures and the harsh winter killed off the tiger muskie before they had a chance to take hold. 

“Sometimes it just doesn’t work out,” Koenig said. “Species like brook trout can reproduce really quickly, and sometimes it’s just not the right combination of factors for tiger muskie to dominate the overabundant species.” 

But stocking tiger muskie isn’t solely for species suppression; it can also benefit the most hardcore of anglers.

‘The fish of 10,000 casts’

Tiger muskie are not only a resourceful, big-bodied predator; they provide a thrilling angling opportunity for those who seek them out in a handful of fisheries across the state. 

“You have to be a pretty hardcore angler to go after tiger muskie,” Jeszke said.

Lakes such as Little Payette Lake, Winchester Lake and Hauser Lake all support populations of tiger muskie and attract die-hard trophy anglers throughout the spring and summer. But even some lowland lakes, such as Lake Lowell in Southwest Idaho and Shepherd Lake in the Panhandle have tiger muskie, and while catch rates are low, they  offer anglers a diverse lineup to fish after.

“They’re a super cool fish,” Koenig said. “From a management perspective they can be a beneficial tool when conditions allow. But from an angling perspective, they’re one of the biggest species in the Mountain West and can be the catch of a lifetime for some anglers.”

Catch of a lifetime is accurate. As Jeszke points out, some anglers might go their whole lives trying to land “the fish of 10,000 casts.”

“They’re incredibly hard to catch, and often one of the highlights of many anglers who’ve been lucky enough to reel one in,” Jeszke said.

Edward Kalinowski got to experience the thrill first-hand back in 2013 when he hauled in the (current) state record out of Little Payette Lake. The tiger muskie measured 52.5 inches and tipped the scales at over 44 pounds.

In Lake Lowell, biologist are trying to reduce the numbers of suckers and carp while more or less coexisting with other popular sportfish, like the lake’s largemouth bass and bluegill.

“It’s important that we balance quality fish management with quality fishing opportunities,” Koenig added. “Introducing a large, toothy predator into a prized trophy fishery might cause some anglers concern, so it’s crucial that we study each fishery individually and provide outreach on the role of these fish.”

End of the line

In total, tiger muskie are regularly stocked in about a dozen waters across the state, many of which are known for their bass fishing. And the two, as far as Fish and Game biologists have observed, tend to coexist without muskies noticeably altering the bass populations. 

“If, however, tiger muskies start to target bass and other sportfish, it’s a pretty easy decision to get rid of them,” Koenig said. “Tiger muskie are hybrids and because of this, they are sterile.”

Once they’re stocked, tiger muskie populations start dwindling because the possibility of spawning is zero. Fish and Game fish managers point out that if a lake’s tiger muskie run out of available nongame species and turn to gamefish, their impact will be limited by both the availability of the lake’s food and their inability to reproduce.