Did Maligne Lake really produce Alberta’s largest-ever rainbow trout? New scientific evidence casts serious doubt

One late May morning in 1980, I watched as local fishing guides proudly paraded the new Alberta record rainbow trout down Jasper’s Patricia Avenue. They had just been to the town post office to have the fish officially weighed, and now they were bringing it to a local fishing store. Laid out on a plank, it looked more like a salmon than a trout. When I asked, I was told the monster fish, weighing 20 pounds four ounces (9.2 kilograms), had been caught by a visiting angler. I was impressed, but not entirely surprised, because I’d recently seen a fish very much like it. It was almost exactly the same, in fact.

The previous weekend, I had hiked to First Lake in Jasper National Park’s Valley of the Five Lakes and watched an immense rainbow trout cruising slowly around a shallow bay, where groundwater springs percolate up into the marly bottom. As the fish searched for a place to spawn, it repeatedly swam past me, almost at my feet. I could hardly breathe with the excitement of seeing a rainbow so huge. I made up my mind to come back and hunt for it when the angling season opened there on the July long weekend.

So, as I watched the procession of grinning young men with their huge rainbow trout, I suspected immediately it must have come from First Lake, even though it was closed to fishing. I also suspected it might even have been the giant fish I’d seen. The men insisted, however, it had been caught higher up in the Rockies in Maligne Lake, which had just opened to fishing. That seemed very strange to me, as that lake simply doesn’t produce such big rainbows.

But all I had were my suspicions, which were shared by others who knew Maligne well, and who knew that really big rainbows were only ever caught in a few of the small, productive lakes in the lower-elevation Athabasca Valley, including First Lake. Suspicions aren’t proof, however. And when I shared my doubts with a local fishing outfitter, he got defensive and angry, insisting he’d even seen that very fish rise in front of his boat the week before. Well, what was I going to say to that?

We anglers are notorious for stretching the truth. We almost always round up, making our catch a bit longer, a bit heavier, and a lot bigger. If it’s a sin, it’s a sin of over-enthusiasm, wishful thinking and/or braggadocio. But some tall fishing tales are different. Some gloss over misdeeds, and they need to be exposed, sooner or later. In the case of Alberta’s record rainbow, it’s 45 years later.

Why the delay? Mostly, it was to protect an exceptional lake’s rare stock of giant rainbows from gaining too much attention. That lake is no longer home to trout, however, so the true tale can finally be told about Alberta’s record rainbow trout—a fish that simply does not belong in the record book. And it all comes down to a few basic ecological facts to prove it.