Expert secrets for catching the giant “triploid” rainbow trout of B.C.

You’d think that when giant rainbows and speckle trout are cruising the waters around you, opting for heavier rods, stouter leaders and bigger baits would result in titanic trout, but Brian Chan says it is not the case.

Brian is one of the most respected fly fishers in the country, and a trout biologist to boot, having spent 35 years managing salmonids in British Columbia. He joined us recently on our Doc Talks Fishing podcast, and what he what he had to share will having you rethinking your big-trout strategies.

And big trout are what British Columbia is famous for, having perfected triploidization in their hatcheries. If you’re not familiar with the process, which can occur naturally, it is when the eggs are bathed for a short period of time in hot water to produce sterile fish. And then these fish can live twice as long, and grow twice was big as natural (or “diploid”) trout.

“People often ask, how the heck was this technique created.,” says Chan. “It was developed by some research scientists in England, way back in the early 1980s. They were probably two mad scientists sequestered in a dungeon and told to figure this out.

“England has a lot private fisheries, so they wanted to grow big fish that would live long, so they’d get the maximum value out of them. That’s where it all started. Triploidization or creating non-reproductive salmon was originally developed in the UK.”

It may have been developed overseas, but British Columbia clearly seized on the process as a way to stock sterile trout and char in lakes, while countering any cross-breeding between non-native eastern brook trout and endangered or threatened populations of native bull trout.

The new tool in the toolbox, as Brian puts it, has also allowed managers to create super-high-quality fisheries because instead of wasting energy on producing eggs and sperm, the fish can devote it entirely to growth. And get this: after working on the triploid process for over 40 years, the British Columbia hatchery system has succeeded in producing only female triploids that live and grow to massive proportions.

“In the interior regions of British Columbia, where we have long, hot growing seasons and a nutrient rich land base, and where the water is high in phosphorus, magnesium and calcium, a five-year-old triploid rainbow trout could be three times as large as a diploid,” says Chan. “They can be huge. For trout standards, we see in some lakes triploids in the mid-teens in terms of weight.

“I have caught female triploid rainbows in the 14 pound range. We’ve got a lake called Stump Lake, right along a major highway just south of Kamloops, that grows some really large triploided rainbows. It’s a big lake, probably 800 acres in size. These rainbows get big by not only feeding on the insects and zooplankton populations when they’re juveniles, but there’s also a population of sculpins in the lake. So they really feed on them.

“I’ve had some spectacular days down there. A couple of springs ago, I was down there fishing with Don Freschi, the host of Sport Fishing on the Fly, and we got into an chironomid (midge) hatch, and we both landed double-digit, Blackwater-strain, triploided rainbow trout. Don’s was probably close to 12 pounds and mine was just over 10. And we caught a bunch of others in the five- to seven-pound range. It was one of those days you’ll never forget. And all the fish we caught were triploids.”

Which brings us back full circle to whether or not it is wise to use stouter tackle to catch titan trout.

“We’re still using six weight rods as the norm,” says Chan. “We do a lot of chironomid midge fishing. It’s the mainstay of our fly fishery. They’re small bugs so we’re using 4X and 5X tippets, so seven pounds and less.  And our flies are tied as small as size 18. They’re tiny little hooks because that’s what they’re eating. But they love them, and the fish get big gorging on them. You’ve got to use something when these fish get so focused on a very specific insect, whether it’s a chironomid pupa, mayfly nymph or damselfly nymph you’ve got to match the hatch.

“It’s a totally different mindset when you’re fishing for bass or walleye or pike, where they’re feeding on a forage fish and they’ll chase after it. These insects or small aquatic invertebrate are lazily in the water column, so the trout expend the least amount of their energy for the greatest return of protein. And that’s how they get gargantuan in size.”

To listen to the entire fascinating podcast with Brian Chan, tune in on your favourite podcast provider, or simply click on the link below and enjoy.