Theses and Dissertations Collection

Negative interactions with nonnative species are a concern for many species including Yellowstone Cutthroat Trout (YCT) Oncorhynchus clarkii bouvieri. In many YCT fisheries, managers are tasked with balancing angler satisfaction and fish conservation. Trying to balance these needs is typified at Henrys Lake, Idaho. Recent surveys have revealed increase in the abundance of nonnative Utah Chubs (UTC) Gila atraria in Henrys Lake. The effect of nonnative UTC on native YCT in Henrys Lake is unknown, but UTC have negatively affected salmonids in other systems. A comprehensive analysis of historical data was conducted to assess long-term trends and identify factors influencing population dynamics of YCT in Henrys Lake. To better understand YCT and UTC interactions, YCT and UTC were radio-tagged in spring 2019 and 2020 to describe their movement and habitat use in Henrys Lake. This research provides insight into possible interactions between YCT and UTC, and provides a comprehensive understanding of factors influencing population dynamics of YCT that can be used to guide management actions.