Probing water temperature for lake trout

The author shows why spring is tops for lake trout. Credit: Gord Pyzer.

The Question

Dear Gord,

Is there a supplier of submersible thermometers in Ontario? Lake trout have been eluding me in a lake near my camp, and your tips in the March/April 2012 issue of the magazine about fishing just below the thermocline (“Trolling time out”) may solve my problem. I just have to find it. Any suggestions?

Ronald Mann
Timmins, Ontario

The Answer

Hi Ron,

I have never understood why no one in the fishing “electronics” side of things—at least that I am aware of—makes a good submersible water thermometer.

With fish being cold blooded, they have to seek out their preferred/optimal water temperature or—in many cases—perish. So you’d think someone would make a unit.  And as you read in my lake trout story, all you would have to do is lower down the probe, locate the depth at which you find the ideal band of 48F to 52F water, and then begin your search from there.

I have a thermometer built into my underwater camera and you can buy downriggers with thermometers built into the cannonballs, so those do the trick for me. But for the life of me I can’t locate a good, easy to use, standalone, submersible probe that I can just drop over the side of the boat.

If you find one, let me know!

Gord Pyzer

Gord Pyzer

Gord Pyzer

Fishing Editor Gord Pyzer is widely regarded as Canada's most scientific angler. Known in fishing circles as Doctor Pyzer, he worked for 30 years as a senior manager with Ontario's Ministry of Natural Resources before devoting all his energies to fishing. A member of the Canadian Angler Hall of Fame, the award-winning writer is also an internationally sought out speaker, tournament angler and field editor with In-Fisherman Magazine and Television. As well, he co-hosts the Real Fishing Radio Show with Bob Izumi. Catch Gord on the Outdoor Journal Radio Show live every Saturday morning 8:05AM EST. If you're in southern Ontario, tune your radio to Sportsnet 590 The FAN AM or visit and listen live online.

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