Of all the major species anglers pursue in the wintertime, lake trout may be the most accommodating. Unlike walleye, sauger, crappies, bluegills, pike or perch, all of them sluggish and selective in winter, lake trout are the least affected by frigid water temperatures, reduced metabolisms, low oxygen levels and negative environmental conditions. In fact, winter represents a relative high point in the lake trout’s annual life cycle, a time of comparative ease, stability, and surprising plenty.

Unlike most other fish that spawn in the spring, lake trout lay their eggs in the fall. In many respects, their seasonal rhythms, recovery patterns and feeding habits are reversed, the Australians and New Zealanders, if you like, of the fish world.

Also, lake trout love cold water. It’s important for ice anglers to back up a few months and view trout in the mid- to late summer, when conditions for trout are at their stressful worst.

As cold-blooded creatures, fish are unable to regulate their internal body temperatures and seek water that most closely approximates their preferred temperature, generally 48°F to 52°F. In late summer, this zone of cool water is found in the middle to lower levels of most lake-trout lakes, often at depths of 60, 80, even 100 feet of water. But to prosper, lake trout need plenty of oxygen, and the deep basin of many lakes, where late-summer temperatures are most ideal, is also where decomposition of algae is most accelerated and where oxygen levels are low.

As a result, lake trout often are forced to navigate between two evils: Rise higher in the water column or swim into shallower portions of the lake—where oxygen levels are good, but where water temperatures are so warm as to approach lethal levels—or, stay down in cooler waters and suffocate.

Fall turnover brings relief to stressed lake trout. When the waters cool so that the entire column is 40°F, there’s no longer any thermal resistance to the mixing of the water layers. With the aid of wind and wave action, oxygen is restored throughout the water column and to all depths and levels of the lake. Surface water temperatures chill further, and soon ice forms along the shoreline to eventually stretch across the lake.

Now wintertime, the living is easy once again for lake trout, partly because their preferred water-temperature range is the lowest of the popular winter ice-fishing species, at 48° to 52°F, as mentioned. Compare that with the temperature preferences of walleyes at 67°to 72 °F, crappies at 68° to 73°F, and even pike at 66° to 70°F, and you’ll see why lake trout are much more active, mobile, and voracious during winter.

Most other species enter a state of near-hibernation, called torpor, during the frozen-water period. Their feeding is greatly reduced, their digestion rates are slow and their growth is limited. Biologists refer to the minimal winter eating-patterns of most fish as “maintenance feeding”—they eat just enough to survive. Even northern pike, fish that like cool water conditions, reduce their wintertime activity levels significantly, growing at a rate of only about 3.9 percent.

But the icy water temperatures play another important role for lake trout. They open up the entire lake for the trout to roam and search for food. During mid- to late summer, high water temperatures and negative oxygen levels combine to make as much as 90 percent of lakes inhospitable and totally out of bounds to lake trout.

In winter, however, when the entire water column and shallows are open to trout for foraging and feeding, ice anglers can make a mistake targeting lake trout only in or near the deep main-lake basin.

While much of the trout population may relate to these main-lake areas, especially to transitional structure features, a substantial portion can also be found in the shallows. I’m always amazed at the number of yellow perch found in the stomachs of trout I keep for shorelunch.

It’s a pattern I’ve found consistent whenever and wherever yellow perch and lake trout share the same habitat, even when more appealing ciscoes (tulibees), whitefish, suckers, and smelts swim in the same body of water.

This is why primary points that lead into 30- to 40-foot bays, where weeds grow in the shallows, can be ideal spots around which to drill ice-holes. Lake trout cruise these flats hunting for perch. Until you’ve seen it, you won’t believe it. Last winter, for example, I experienced one of the most spectacular winter trout feeding-frenzies ever, after my partner and I drilled a series of holes in 20 to 25 feet of water off a secondary point, in the middle of just such a flat (see first diagram). We hooked and released 15 lake trout between 8 and 15 pounds, missing half a dozen others, in less than 45 minutes of jigging. It was a slam-bam slugfest.

Funny thing about the “flat” bite, though. Torrid early in the ice-fishing season, it dies out by mid-winter as the layers of ice and snow thicken. Notice, I was careful to say the flat bite as opposed to the shallow bite, as a sizeable portion of the lake trout population appears to remain in thin water. In many cases, the fish are 10 to 30 feet under the ice, even when they are swimming over 60 to 100 feet of water.

Biologists speculate that the thickening layers of ice and snow block out sunlight penetration, dim illumination levels and otherwise darken deeper waters. Not only do the trout enjoy the cabaret conditions, but the diminished light appears to pull the phytoplankton and zooplankton—the tiny plants and animals that provide the foundation for life—higher up in the water column.

Many ice fishermen don’t realize the degree to which lake trout, even big ones, devour larger zooplankton species. In many lakes, zooplankton constitutes the bulk of the lake trout’s diet, while in other lakes, even when there is an abundance of herring, smelt, shad, shiners and other prey-fish present, lake trout still wolf down the tiny tasty animals. Hence, the thicker the ice, the deeper the snow and the darker the illumination levels, the higher the plankton rises in the water column.

Two other clues serve to strengthen and confirm this under-the-ice, mid- to late-winter locational phenomenon. You see little or no fish activity on your sonar screen, as the lake trout (and often the pelagic baitfish) are hidden in the surface clutter and electronic noise.

And, if you’re fishing from a darkened ice shack, you occasionally spot packs of marauding trout, often behemoths, cruising like sharks directly under your boots. The fish rarely travel alone, making for winter mayhem if you play things right, confirming what many winter anglers already know. Lake trout are the coolest dudes in winter.

*Gord Pyzer, Kenora, Ontario, is a fishery scientist and an In-Fisherman magazine field editor who has written numerous award-winning articles for In-Fisherman publications and appears along with In-Fisherman editors on In-Fisherman Television.