Shallow-water lake trout: How to catch the giant lakers most anglers overlook


The past couple of seasons, my grandson Liam and I have caught more and bigger lake trout in easily accessed, heavily fished small- and medium-sized waters than in any previous period. Our secret to catching these giant fish topping 30 pounds? Pushing the limits and thinking outside the box. Way outside.

In short, Liam and I have discovered seemingly untouched lake trout populations by prying open the cold-water window higher in the water column. Understand what I am saying? Lake trout survive best by living in water temperatures between 48°F and 54°F, but the biggest fish we caught last season—a 30-pound-plus monstrosity in a modest-sized, cottage-crowded lake—smashed the bait Liam was moping in 38 feet of water at high noon on the hottest day of the summer.


I was so proud of our discovery that when Liam and I recently interviewed Christian Therrien for our new “Doc Talks Fishing” podcast, I thought I was going to at least surprise, if not shock, the lake trout guru with our success stories. Well, guess who had his eyes opened? It turned out Therrien had already come to the same conclusion.

“We’ve discovered that lake trout will leave the cold water to make foraging bouts into quite warm water,” Therrien says. “A great example is Elboga Lake near Sudbury. It’s a fish sanctuary, so I don’t mind dropping the name. It’s the middle of a July heat event, the surface-water temperature is 85°F, and we’re catching them up tight to shore on swimbaits. They’re smashing them. Like, they’re coming to the boat and we’re figure-eighting them.”

Scientist Christian Therrien says ciscoes are key to catching giant lakers

Not that I should have been surprised Therrien already knew lakers would venture into warm water to feed—his doctoral work is very cutting edge, after all. For example, he discovered that when bucket brigades illegally introduce smelt into pristine lake trout waters, the lakers develop beriberi disease and suffer massive heart attacks. He also contends the very name “lake trout” is a bit of a misnomer. “Lake trout don’t just live in lakes. They also live in rivers. Some populations go out to sea. I’ve seen them in lakes smaller than 17 acres, and where the deepest water is 37 feet deep. They’re incredibly plastic, and incredibly diverse.”


Back to the pattern we both independently discovered. What’s so freaking coincidental is that it’s identical to what astute muskie anglers have been exploiting for years, only in the reverse. The big toothy critters don’t hesitate to leave their warm, shallow comfort zones to cruise along the top of the cold thermocline, assaulting school of ciscoes, suckers and whitefish before returning to their spa-like resorts to digest.

We’ve discovered that lake trout will leave cold water to make foraging bouts into quite warm water

Likewise, Therrien says lake trout also live in their preferred optimum temperature, where their metabolism functions at peak efficiency and they’re not quickly burning energy. But if there’s no food in that range, they’ll leave and sacrifice energy. It’s much like us stepping outside of our air-conditioned houses when the thermometer tops out—we’re going to start sweating.


“I was fishing a big lake in northern Ontario with a very diverse fish community,” says Therrien, offering an example. “It has 17 different fish species, but no predatory fish other than lake trout. And they feed on everything. We’ve caught them on sand flats eating big golden shiners that look like goldfish. And it’s like, man, how did they swim two kilometres to get up here, gorge themselves, then hurry up and get back? The idea that lake trout are a super-deep, cold-water-inhabiting species is not entirely true.”

Ciscoes are a crucial forage fish for lakers

What is true for Therrien, though, and he confesses as much when I prod him, is that he wouldn’t fish for lakers in a waterbody that didn’t also contain ciscoes as a primary prey species. “I’ve caught a lot of lake trout in my life,” he says. “I like catching big fish, but it’s hard to catch a giant lake trout in a lake without ciscoes. They’re prey fish that can attain pretty big sizes.”

According to Therrien, ciscoes are really fatty and calorically dense, so they’ve got everything a lake trout needs. And as a result, he notes, the growth rate of lakers in lakes with healthy cisco populations is incredible. Says Therrien: “It’s the healthiest food a lake trout can get.”