Males don’t usually have two Y chromosomes. YY technology is a well-studied and widely used fisheries management tool. These YY brook trout carry two Y chromosomes instead of an X and Y, and can only produce males when they spawn. When paired with removals of fish, the population becomes skewed toward males over time. With fewer females in the population, fewer trout are born, and fisheries managers can control the population of non-native fish, restore native trout, and maintain great fishing the whole time. In time, the goal is to introduce native species, namely Rio Grande cutthroat trout, once the population of non-native species is more controlled, Phillips said.

Once the trout are stocked in the stream, the team met back down at Bonito Lake, where the remainder were released. Bonito is one of the Department’s Open Gate properties – a privately owned property that has entered into an agreement with the Department to allow members of the public to access the property under certain guidelines. The lake, considered a gem for a weekend fishing excursion, is open for fishing, but not for boating or swimming.

Someday, anglers may spend their weekends at Bonito Lake targeting Rio Grande cutthroat trout there after the YY brook trout have done their important work. In the meantime, brook trout will continue to be part of the lake’s recreational fishery.