For nearly 15 years, Idaho Fish and Game has encouraged anglers to kill trout. Ads have been placed. Limits have been eliminated. And, most interesting, cash prizes have been offered.

All so that rainbow trout can be killed as efficiently as possible in the South Fork Snake River.

Of course, the reason behind the initiative (“rainbow trout suppression”) are virtuous. After decades of stocking nonnative rainbows on top of cutthroats, Idaho is taking action. The South Fork Snake River has a remarkable carrying capacity for cold water fish. But because rainbows and cutthroat trout are so similar, their ecological niches overlay. As a result, the native cutthroats are unable to thrive. Furthermore, their genetic similarities allow for crossbreeding. “Cutbows” are fine for fighting and eating, but they are a real thread in watersheds that represent historic populations of either parent species.

Around 2010, Idaho Fish and Game decided to take action.

The limit for rainbows on the South Fork Snake River is no limit. If biologists could electroshock all the rainbows out, or if there was a chemical means to taking all of the ‘bows without hurting other species, they would. But this portion of the snake sees enough angler pressure that culling is a viable aspect of the initiative to support cutthroats.

What has garnered attention from local and out of town anglers is the real incentive: cash. Pounds and pounds of freshly caught rainbow trout is good. But a check for up to $1,000 is even more enticing. Idaho has used tags in the past to give anglers something to “claim” for award winning fish. Along with the bounty, the tag gave empirical data regarding how the rainbows moved and lived. Recently, Idaho upped the ante by switching to tiny radio tags. Anglers deposit fish heads (at least) in boat launch coolers. The state collects the labeled bags of fish parts and then scans for radio tags. Lucky anglers get checks; the state gets data.

Here is some initial data regarding “rainbow trout suppression”  on the South Fork Snake River. It reflects ambitious efforts by a state conservation organization to right wrongs from decades ago. It also reminds anglers that some fish are better in some places than other fish. And, that you can – and sometimes should – eat fish.

Meateater’s “Cal in the Field” had an episode on Idaho’s efforts on the South Fork Snake River. It is worth watching: