Entirely Genetic Bliss

By Beacon Staff

Rainbow trout don’t belong here. Still, I just can’t seem to quit them.

Rainbows may be the most popular gamefish in the Rocky Mountain region, but other than the upper northwest corner of Montana, where the state is nicked by the Kootenai River, this is westslope and Yellowstone cutthroat country.

Rainbows were popular with the folks who first settled the West. The fish fight hard, including the habit of taking to the air when hooked. Those leaps out of the water are like lightning bolts, especially when you’ve got a good-sized fish on the line. Rainbows are also fine fish to eat. So there are good reasons why we are so fond of these fish, and why folks moving into the interior West brought along the spectacular trout they first encountered in coastal streams of the Pacific Northwest.

It turns out rainbows were a good choice for this biological experiment. The fish do well in a hatchery environment and a sort of mutt trout was soon produced. Many of the original traits the source fish had developed to survive in the wild were replaced by traits hatchery managers preferred.

Hatchery rainbows did well in confined raceways and thrived on a diet of fish chow pellets. The fish were adaptable to a variety of conditions in trout habitat and didn’t share the peculiarities some of the native fish of Montana developed in isolation from hard-scrabbled competitors like rainbows.

The fish are so pervasive that most folks have come to view them as native.

In much of the West, state game departments spread rainbows around in trout habitat like Johnny Appleseed making the wilderness safe for fans of hard cider.

If you want to know more about the human-induced rise of rainbow trout, Anders Halverson takes an in-depth look at our love for the fish in his book, “An Entirely Synthetic Fish.”

Rainbow and cutthroat trout share a common ancestor, a trout that evolved in the mountain streams of Mexico in colder, wetter times. The fish then spread north during the periods of glaciation that led to the rise and fall, and rise and fall again, of Glacial Lake Missoula. I’m over simplifying here, but basically the cutts moved into the Columbia River Basin first, followed by rainbows. What kept the two fish apart was the development of barrier falls on the Snake, Clark Fork and other rivers in the basin.

The late arriving rainbows couldn’t make it to places like the headwaters of the Flathead River, so westslope cutthroat evolved to thrive along side another native fish, bull trout.

What we’ve come to view as acceptable ecological practice where trout are concerned has changed dramatically during the last 50 odd years. Hatchery put-and-take trout were once viewed as an acceptable replacement for wild fish lost due to dams and other human activities that destroyed fish habitat. I’ve seen attitudes change since I first got into fly fishing back in the early 1980s when I joined a fly fishing club that worked to restore trout habitat in the mountains of Southern California.

That period was marked by the rise of the wild trout ethic. Dopey hatchery fish were no longer good enough. Anglers wanted wild fish, born and raised in streams, rather than concrete raceways.

Now we’re moving into the native fish era, where the focus is on preserving and restoring populations of trout which were here before we started mucking things up. So if you’re into native fish, Montana, Wyoming and Colorado are off the list when it comes to rainbows. You have to head west if you want to fish for the descendants of those late-arriving rainbow trout in places they populated all on their own. That means the Idaho panhandle, or the coast, or, for the greatest fishing for native rainbow trout left on the planet, Alaska.

Native or not, the fish are worth pursuing. I love cutthroats, but they rarely display the passion of a rainbow when hooked.

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