Northern Utah’s Logan River is known for its solitude and grandeur. Drive just a few miles up Logan Canyon in Cache Valley and find yourself in a wild setting on the bank of a picturesque mountain stream. It would be difficult to find a place in Utah that is more accessible and yet so peaceful.
However, just a few inches beneath the riffles of the Logan River, a war rages.
This conflict has gone unresolved for more than a century. The combatants fight continuously all day, all night, and all year.
The indigenous defender is the Bonneville cutthroat trout, which migrated here hundreds of thousands of years ago from the west coast of America by way of the Snake and Columbia rivers. They’ve been here ever since, making this Logan River cutthroat army the largest wild and natural population of its kind. Presently, cutthroats hold the upper river, above Twin Bridges or thereabouts.
Invading from downstream is the brown trout, whose antecedents hail from Eurasia. The brown trout isn’t an intentional trespasser; they were stocked here in the 1880s by humans who wanted more fish to catch. However, brown trout are aggressive, and they don’t know or care that the Logan River used to belong to some other species. Brown trout dominate the lower river, especially in the neighborhood of Third Dam.
And so they fight.
The middle portion of the river is a “no-trouts-land,” where the two species meet to wage their desperate struggle. They contend for living space, compete for forage, and, when it’s convenient, they devour each other with gusto.
Which will prevail? Each species has its advantages.
The brown trout are indisputably stronger, tougher, and meaner. They tolerate low water quality and wide swings in water temperature. When brown trout encounter cutthroats of their same size, they aggressively drive out the more-docile cutthroats. Every year, the brown trout gain a little ground, pressing inch by inch upstream.
Cutthroats may not be great fighters, but they are resilient, having survived clear-cut logging, overgrazing, and the damming of the river. The cutthroats were here first, too, so they hold the high ground, and it’s much easier for fish to move downstream than up. And the cutthroats rule the upper tributaries of the Logan River, which they use to spawn and replenish their numbers. But perhaps most importantly, the cutthroats have an immensely powerful ally: humans.
That’s right. The race that brought the brown trout here in the first place now sides with the cutthroats. The humans could easily exterminate all brown trout in Logan River, from its headwaters to the confluence of the Bear River, but that’s not what’s happening. Instead, conservation measures, such as strategically placed barriers to fish passage and fishing regulations that protect cutthroats during their spawning season, give the natives a fighting chance against their fierce invaders.
Fly anglers, too, favor the cutthroat trout, which they fondly refer to as “cutties.” Fly anglers seem averse to harvesting cutties, releasing them instead unharmed after capture. Opinions vary among experts about how much catch-and-release practices actually help the Cutthroats, but this is war, and these natives, besieged by a relentless and superior foe, can use every advantage they can get.