Panfish Week: Tracking Perchzilla: Parameters for Monster Perch

On relative scales of wow, a giant 14-, 15-, or dare I say 16-inch yellow perch cuts one of the more impressive profiles in the freshwater world, especially awe-striking as the animal enters the crystalline looking-glass of your ice fishing hole. North American perch of those colossal dimensions certainly rival any 30-inch walleye or 50-inch muskie. In my book, a truly giant perch is even more impressive because I’ve fished a lifetime having seen only a handful of perch that big.

Jason Mitchell tells me his lifelong quest to crack the 3-pound barrier persists today, even though he’s clutched 10 bona fide 2-pounders from places like Devils Lake, and more recently, Cascade Lake, Idaho. Within other serious perch circles, the true measure of a sumo perch is measured not in pounds or inches, but in black stripes bejeweling its body. A seven-striper’s a real head-turner. While a legit eight-striper is the stuff of legends—theoretically possible, but only on a handful of North American waters. If a 3-pound, eight-striper sounds implausible, all sense of reality goes haywire when you see pictures of 5-, 6-, and even 7-pound European perch from overseas. (American perch are of the species Perca flavescens, while European perch are another species, Perca fluviatilis.)

I’ve gotten to know a couple Swedish perch anglers who fish a European tournament circuit called Perch Pro, and they’ve relayed some fascinating facts. “Our perch often grow extremely slow, though they can live over 20 years and exceed 24 inches in length,” says Mario Sbrzesny, an exceptional angler from Stockholm. “In Europe, our benchmark for a specimen-sized perch is 20 inches, a fish we call perchzilla.”

North America’s perch and European perch exhibit similar habitat and feeding tendencies, flocking to expansive flats with low-­growing vegetation. Both species travel together by size or year-class. According to Sbrzesny, however, giant Euro perch frequently crush bass-sized topwater lures while hunting baitfish in small packs—an unheard-of tactic in America. Watch YouTube’s Perch Pro series for a compelling, expert view of the European perch scene, and to witness some absolute ‘zillas.

The two species of perch are believed to have developed after perch inhabiting once-connected European and North American land masses evolved separately after the land masses split apart. Speciation is the term that describes what happens when a group within a species separates from other members of the species and develops its own unique characteristics—a result of disparate environmental demands.  

Today, North American perch inhabit a wide breadth of waters from west Canada to New Brunswick, south to South Carolina and west to Kansas. A 14-inch 2-pounder sets the benchmark for an American trophy. A fish of those proportions wouldn’t, however, raise many eyebrows in Europe. Naturally inhabiting lakes, rivers and the brackish waters of the Baltic Sea across large swaths of Europe and northern Asia, European perch have also been introduced into Australia, New Zealand, and South Africa. In 2010, the River Meuse, Netherlands produced a colossal 8-pound 4-ounce specimen.

Perch Populations Today

Back on American soil, it appears that perch populations in some regions may be undergoing a transformation in the opposite direction. According to recent research by Beth Holbrook and Bethany Bethke of the Minnesota Department of Natural Resources in 2019, perch populations may be shifting toward smaller individual fish. “Our pilot work has shown that perch in some lakes are now maturing so early and at such small sizes that they can potentially live out their entire life cycle without being detected by standard DNR sampling gear,” noted Holbrook, a Minnesota DNR research scientist. Holbrook’s team has turned to gill nets with smaller mesh sizes to capture and accurately assess perch populations.

Due to a historic lack of perch-specific research, relatively little is currently known about the life history and feeding and spawning habits of these critical, though oft-ignored species. To get a clearer picture of population trends and other habits of yellow perch, Holbrook and Bethke initiated a multi-year statewide study involving 24 regional Minnesota DNR offices and dozens of lakes, where experimental sampling methods such as shallow fall electrofishing and fine-mesh gill nets will be utilized. They’re also identifying fish ages via otolith inspection, as well as sex and age of maturity of individual perch.

Initial findings show that in 14 of the 20 study lakes, males are reaching maturity at age 1. The smallest mature fish was a 2-inch male from Green Lake near Spicer, Minnesota. “Our research continues to show that perch bigger than 5 inches are decreasing in numbers and that those perch aren’t reaching maximum sizes as large as in the past,” Holbrook says. The study, “Assessing Yellow Perch Populations with Experimental Sampling Gears,” which combines new survey data with population assessments all the way back to the 1970s, is slated to conclude in 2023.

Holbrook suggests that, especially in lakes where anglers have historically harvested limits of large perch, the decline in size structure and maturity could become a major problem. “We’ve found that the size of maturity is also correlated with maximum size,” she says. “So if fish mature earlier, they’re not getting as big.” Holbrook believes warming waters, a shift in perch predators, and zebra mussels have all contributed to producing early maturing perch. Invasive mussels filter vital nutrients from the water, increasing underwater clarity and making it easier for predators to capture young perch.

As we’ve noted in past articles, perch are somewhat unique in their double-edged sword-like vulnerability. Young perch are heavily targeted and preyed on by bass, pike, walleyes, and large perch. Meanwhile, large perch also remain highly desirable to anglers. Even among panfish, such as large sunfish and crappies, for which anglers have begun to understand the value of selective harvest, perch continue to be subjected to wholesale harvest, regardless of how large.

Conversely, Jason Mitchell, legendary former Devils Lake guide and angling personality, suggests that perch in shallow, fertile North and South Dakota lakes grow so fast and are so vulnerable to winterkill that anglers feel justified in target-harvesting the largest specimens. “On a universal scale, you really can’t compare perch population dynamics to bluegills because perch growth rates vary so much from region to region,” says Mitchell, among the most well-traveled perch anglers in North America. “Nor can you compare perch in Idaho or the Dakotas to perch in Minnesota or the Great Lakes. Perch growth rates and life span, water fertility, and harvest all play roles.”

Particularly across the northern boundaries of their ranges, however, when large, mature members of pike and bluegills, for example, vanish from populations, both species have been shown to adapt by maturing at earlier ages. Once fish begin maturing early, they don’t benefit from typical growth rates, stunting their ultimate size. When fish such as perch mature later, such as age 5 or 6 rather than age 1, most of the energy they derive from food goes toward growth. But when sexual maturity is reached at age 1, 2 or 3, most of the food energy drives the rigorous demands of reproduction rather than growth—and hence, perpetually small fish.

Perchzilla Parade

An intriguing case study in perch population dynamics, Cascade Lake, Idaho, has for the past decade likely produced more truly gargantuan fish than any water in America. Beginning in 2004, Idaho Department of Fish and Game (IDFG) biologists began a major restoration project aimed at restoring perch stocks. Researchers discovered in 1997 that the lake had experienced virtually no juvenile perch survival during the previous decade, with almost no perch greater than 4 inches in the lake. Poor water quality due to excessive runoff from cattle operations, sewage effluent, and erosion all contributed, resulting in low dissolved oxygen and poor fish recruitment. The agency worked with Idaho’s environmental agency and enacted a water-quality improvement plan that showed dramatic improvements by the late 2000s.

And yet, the biggest culprit, they found, was a native predator known as the northern pikeminnow, or squawfish. Estimates showed a Cascade Lake population of up to half a million pikeminnows, which average 2 to 4 pounds but can exceed 20 pounds. Estimates further indicated that on a diet of just 10 percent perch, Cascade Lake pikeminnows could consume 68 million perch annually.

As a result, in 2004, Idaho began pikeminnow spawning suppression efforts on the North Fork Payette River. By 2006, almost no spawning pikeminnows were observed, setting off a perch renaissance, aided by the stocking of 800,000 adult perch. Because the lake contained next to no perch at that time, the new transplants had access to an abundant food supply, exhibiting staggering growth rates and reproduction in seasons to come. Three Idaho state record specimens have been caught since, including a 16.25-inch, 3.22-pounder by Adam Mann in March of 2021.

Mitchell, who has fished Cascade several times in recent years, believes the lake continues to offer excellent fishing. Like most top perch waters, Cascade offers two distinct patterns: small and midsize (8- to 12-inchers) fish feeding on bloodworms, and bigger perch cannibalizing small perch. Just like bites in Minnesota, the former calls for tiny baits or spoon-jig dropper combos and finesse-like jigging retrieves; while perch-eating perch allow for a bit more aggression with jigging spoons or ripping baits like the Rippin’ Rap.

“Last winter when we visited the lake, it felt like 90 percent of the perch were less than 5 inches,” Mitchell says. “In almost every hole we drilled, we’d see a 2-foot layer of small perch near bottom, all feeding on bloodworms (midge larvae). But anytime a big perch approached, the small fish would vanish from your depthfinder and you’d often get bit right away.

“The best way to up your odds of contacting one of these big fish on Cascade is to use walleye tackle—spoons and darting minnows—on classic reservoir walleye structure. We’d focus on little points or inside turns along the primary break, with 25 feet being a key depth.

“An alternative pattern, which produced our biggest fish, focused on 15- to 24-foot depths, often on flats adjacent to the river channel or points protruding from those flats. Channel bends also attracted bigger perch. If you’re a seasoned walleye angler who’s geared to run and gun and move locations, you’ll be comfortable fishing Cascade perch,” he says.

Another perspective comes from South Dakota walleye guide and tournament angler Brian Bashore, who’s also visited Cascade Lake for several winters in a row. Like Mitchell, Bashore believes the biggest 14- and 15-inch perch exhibit solitary tendencies. “Big perch come through higher off the bottom, and they’re usually super aggressive. These fish often come through in waves. Last winter we got a lot of 12- and 13-inchers and several 15s in two days of fishing—mostly in the same vicinity near Sugarloaf Island.  

“We play a lot of keep-away with smaller perch and try to stick with Rippin’ Raps, Chubby Darters, and Tikka Minnows—or any other favorite 2- to 3-inch lure—to attract larger specimens. When the bite turns tougher, or fish key on bloodworms, we’ll add a dropper chain to a spoon, tipping it with larvae. Locally, anglers use redworms, which resemble tiny earthworms or bloodworms.

Perch Populations Beyond

Currently, there’s no harvest limit on Cascade Lake perch, Bashore notes. “We see a ton of fish leave the lake in buckets and an almost endless stream of anglers departing the lake on snowmobiles,” he says. “It feels like we need to start limiting harvest there, to a degree. (Cascade currently has no perch bag limits.) We’ve seen our catch rates and numbers of giant perch decline a bit in recent years. No doubt, the lake is receiving more pressure from perch anglers each year.”

According to IDFG reports, Cascade’s big perch may once again be on the decline, as indicated by both fall gillnetting and angler-reported harvest at survey sites. In 2013, anglers harvested approximately 50 percent of the adult perch population. In 2014, that number dropped to 30 percent and under 20 percent in 2019. Regional fishery manager Jordan Messner says that some classic recreational perch fisheries see annual harvest rates top 60 percent of the population.

“Our harvest-rate information indicates that harvest is not responsible for the perch decline in Cascade,” Messner reports. “Rather, the likely cause is low survival of 1- to 3-year-old juvenile perch, which serve as the main prey source for many predators, including larger perch. Pikeminnow numbers have remained stable since our last suppression efforts in 2015. We also believe with low harvest rates on jumbo perch, many will die of old age, and as that occurs, we will see a natural reduction on juvenile perch.”

 Mitchell offers a compelling point regarding yellow perch ages, growth rates, and their dynamic impact on various fisheries around the country, from Cascade in Idaho to Devils Lake in North Dakota to Lake Winnibigoshish in Minnesota and beyond. At Cascade, a 14-inch perch can be 8 to 14 years old, an extremely long lifespan for the species. Mitchell: “In the Dakotas, perch often live to just 4 or 5 years, growing quickly to large sizes in these fertile, food-rich environments.

“On Devils Lake, rising water creates a more abundant pike population, which often leads to a perch population crash. In low water, smaller lakes connected to Devils become cut off via roads, and fish get really big before overpopulating and then becoming runts. But it’s a different story in Minnesota and places like Big Winnie, where there’s slower growth and high angler harvest and perch size continues to show a decline.”

Michigan’s Lake Gogebic offers an historic trophy perch fishery. In recent years, harvest of top-end size perch coupled with slower growth rates led Michigan to reduce the daily limit to 25 fish, with only 5 of those being 12 inches or larger.

If we’re being honest, no one needs to fillet 25 perch. The main problem, as I see it, relates to the nature of the larger 12- to 14-inchers. Almost everywhere you go, big perch strike terror in schools of smaller perch. Perchzilla is typically the most aggressive fish in the neighborhood, which also means it’s the first fish to be caught. Historically, almost no one harvests perch selectively (keeping 8- to 11-inchers and releasing larger ones).

As Mitchell aptly asserts, where growth rates produce big perch inside of 5 years, and where winterkills are common, selective harvest may be a moot point. But everywhere else, it’s past time to follow the models we’ve established with other species. Ultimately, regardless of where you are, a trophy fish is exponentially more valuable and beautiful swimming around and making baby fish than it is languishing in a bucket.

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In-Fisherman Field Editor Cory Schmidt is an outstanding multispecies angler and exceptional writer on the sport. He contributes to all In-Fisherman publications.

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