CASCADE, Idaho — Wisconsin has long sent legions of ice-fishing anglers north or west to chase yellow perch at famous destinations like Lake Winnibigoshish in Minnesota, Devil’s Lake in North Dakota, and Lake Gogebic in Michigan’s Upper Peninsula.
Those sites remain popular, but growing numbers of Wisconsin perch fanatics are pushing Idaho’s Lake Cascade atop their bucket lists, given how it redefines the term “jumbo perch.” Most Wisconsin perch nerds call 11- to 12-inchers “jumbos,” but Lake Cascade’s perch must measure 13 to 14 inches to achieve “jumbo” status, and 15-inchers aren’t rare.
At least that’s what my wife, Penny, and I concluded while fishing Cascade in early September with our friends Chris and Jessie Weber. The Webers moved to Cascade from Wisconsin nearly two years ago after fishing there on vacation.
Lake Cascade is actually a 47-square-mile reservoir, an impoundment of the North Fork of the Payette River. It’s 75 miles north of Boise, and ranks as Idaho’s fourth largest lake or reservoir.
Penny made the signature catch of our five-day trip to Lake Cascade, landing two perch in three minutes that, when laid nose to tail, measured over 30 inches. One was just over 14.75 inches long, and the other 15.25 inches. Each exceeded 2 pounds, and might have weighed 3 pounds if she had caught them six months from now when they’re laden with eggs.
Be warned, though: Cascade’s perch don’t jump into your boat. Our group typically caught 20 to 35 perch during our six-hour outings. You can also expect to catch many respectable smallmouth bass, another non-native fish; and smatterings of rainbow trout over 20 inches.
Further, Lake Cascade will never be a day-trip or weekend getaway for Wisconsinites. Penny and I flew to Boise and rented a car, but if you drive from central Wisconsin – say, Stevens Point – you’ll cover 1,663 miles. That’s 10 times farther than Lake Gogebic, a 163-mile drive; 5.5 times farther than Lake Winnibigoshish, 300 miles; and 3.3 times farther than Devil’s Lake, North Dakota, 500 miles. (It will seem even farther when driving in winter, as my friend Mark Endris and I learned in early March.)
Even so, Wisconsin sends more perch anglers to Lake Cascade than any other state. Weber, who guides for Tackle Tom’s bait shop in Cascade and the Tamarack Resort near Donnelly, said 75% of his clients are cheeseheads. The rest come from Iowa, Michigan, Minnesota, Nebraska, North Dakota and South Dakota.
Meanwhile, most Idaho anglers remain more curious than intrigued about perch. They prefer rainbows and kokanee salmon, the landlocked version of sockeyes. Still, some locals appreciate perch as table fare, and drive up from Boise and its suburbs to fish with Weber.
They also know what it’s like having their hearts broken by fickle Western reservoirs and their fisheries. Unlike Wisconsin’s “flowages” such as the Gile, Willow, Chippewa, Dairyland, Petenwell or Turtle-Flambeau, Western impoundments aren’t just another big lake with stable populations of native fish.
Mike Thomas, regional fisheries biologist in McCall, Idaho, oversees Lake Cascade. He said no two Western reservoirs are alike. Their waters often grow warm in summer, helping non-native fish like crappies, yellow perch, lake trout, brown trout, smallmouth bass, and hatchery rainbows push out native cold-water species of trout and salmon.
In addition, besides generating power for nearby towns and cities, Western reservoirs must store and reliably dispense water for filling bathtubs, washing dishes, flushing toilets, and irrigating crops across wide regions. Those demands only keep growing as Boise booms and droughts deepen.
“Water levels that favor spring walleyes might not be good for irrigating crops,” Thomas said. “Our reservoirs also don’t have myriad prey species like fathead minnows to support a wide variety of predatory fish. The fisheries in Western reservoirs are largely artificial, and we don’t have many management levers to pull. Plus, conditions are always changing, so something that worked 20 years ago might not be an option today.”
For instance, roughly 30 years after the dam was built at the edge of town in 1948, Lake Cascade provided “extremely high” catch rates on perch during the 1980s. That success didn’t occur overnight. Idaho Fish and Game biologists had to treat the lake’s tributaries with rotenone over 100 times during the 1960s through 1974 to kill and remove 450,000 Northern pikeminnows, an unpopular predatory fish whose appetite was virtually wiping out perch.
Perch then thrived in Cascade until the early 1990s, but collapsed by 1997 even though the lake at one point held an estimated 1.6 million juvenile perch. This time, however, the pikeminnow population stopped rising, even as they devoured the young perch. The agency then poisoned and removed over 30,000 adult pikeminnows the next few years. The biologists controlled the remaining pikeminnows by swamping Lake Cascade with over 860,000 perch stocked from stunted lakes within a 10-hour roundtrip drive.
Those perch then pulled off a hatch of “Biblical proportions” in 2008 that fueled the current boom of jumbos. Unlike Wisconsin perch, which live to age 7 on average, Cascade’s perch can live over twice as long, maybe because they don’t encounter large predators like walleyes, muskellunge and northern pike.
“When Cascade’s perch reach 8 inches, nothing can eat them except anglers,” Thomas said.
Thomas is cautiously optimistic about Lake Cascade’s perch, but said their future won’t be determined by simple “levers” like minimum-size or bag limits, of which Cascade has neither.
“Fishing pressure is low here,” he said. “Our tag-return studies show only 10% to 12% of our perch are being caught, but studies on Winnibigoshish showed 62% exploitation rates, and a study in Iowa showed 22%. Our data suggest that for every perch caught by anglers, two die of natural causes.”
The agency surveys Cascade’s fishery each fall with gillnets. The 2021 study found perch averaging over 10 inches, an uptick from recent lows in 2018. “There’s still a lot of perch over 13 inches out there,” Thomas said. “We don’t turn a blind eye to angler harvest, but we have no problems making perch. The lake produces tons of juvenile perch, but a lot of them don’t reach the age or size anglers want.”
Thomas said perch might even be limiting their own numbers through predation. “We’re trying to better understand where the population’s bottleneck might be,” he said. “We want to learn how perch, smallmouth and pikeminnow populations overlap and interact. We expect good fishing ahead, but we’re always trying to find the best way forward.”
Penny Durkin and Chris Weber show a 2-pound perch she caught while fishing Lake Cascade in western Idaho in early September. — Patrick Durkin photos
Perch measuring over 15 inches aren’t rare on Idaho’s Lake Cascade, possibly because they can live 16 years, over twice the life expectancy of Wisconsin perch.
Chris Weber, a Lake Cascade fishing guide, unhooks a jumbo perch.