Stocking Brookies to Save Cutthroat

I’ve had the pleasure of documenting many cutthroat restoration efforts over the past decade, mostly in Utah, where I grew up. But this recent story from Colorado Parks and Wildlife (CPW) is one of the most interesting cutthroat conservation tales I’ve ever heard.

Rachel Gonzales wrote the story for Colorado Outdoors, and I highly recommend you read the entire thing. What she builds up to is the first treatment of its kind to use brook trout to help restore native cutthroat populations.

How is that possible, you ask? Don’t we know that brook trout out-compete cutthroat, literally forcing the native fish out of the water? Yes, we do. And we know that total eradication of brook trout is usually only possible through rotenone treatments—poisoning a river or lake.

But the scientists over at CPW decided to think about things differently, and recently hatched a plan to stock YY brook trout in creeks within the Williams Fork River headwaters. By stocking YY male brook trout, biologists ensure that every offspring those fish produce is male. Stocking these “Trojan Brook Trout” into a river that’s inhabited by both cutthroat and brookies will eventually create a population of male-only brook trout. Without any females around, the brook trout will eventually die out, leaving the cutthroat to take back their historical native range.

It’s an innovative technique, and one that doesn’t require a piscicide like rotenone. This keeps genetically pure populations of cutthroat trout—the fish that are found in Williams Fork headwaters—alive and not dependent on a hatchery to reclaim them.

Again, Gonzales does a wonderful job with her story, and I suggest you read the whole thing here.