During the retreat of the glaciers at the end of the last Ice Age, a plug of glacial rock dammed the narrow gap in the front range just west of what is now Frank Slide in the municipality of Crowsnest Pass. Behind the dam, a lake of meltwater rose to straddle the Continental Divide. The lake was naturally colonized by westcoast cutthroat trout previously confined to the watersheds draining westward into the Pacific Ocean.
Eventually, the plug burst, flushing the migrants throughout the east-side watersheds, establishing a separate, isolated population of cutthroat trout. Thus, the cutthroat became the native trout of the rivers and lakes of Alberta SouthWest.
Pure populations of cutthroat continue to thrive in the higher-elevation tributaries, away from the main river flows where pioneer anglers introduced the genetically dominanting rainbow trout, a native of northern California. The hybrid "cutbow" has become common throughout the region, and most particularly in the Crowsnest River. The cutbow combines the distinctive red jawline of the cutthroat with the red lateral strip of the rainbow.
Three fly shops serve visiting anglers. Two of them, Crowsnest Café and Flyshop and Crowsnest Angler, provide guide services. Alberta Rose Anglers specializes in hand-craft bamboo fly rods.