Temperatures on the rise in Henrys Lake, Idaho: Retrieving lake surface temperature from Landsat archives

ABSTRACT Objective Climate change is expected to significantly impact freshwater fish species, making the conservation of important native species difficult. Henrys Lake in eastern Idaho is a large, shallow lake that is an important habitat for the Yellowstone Cutthroat Trout Oncorhynchus virginalis bouvieri, a native fish in that basin. This study investigates long-term water surface temperature trends in Henrys Lake using Landsat satellite imagery from Landsat Collection 2 Level 2 archives. Methods Over 180 Landsat images were collected from the months of May–October in 1984–2024. We corrected water surface temperatures obtained from Landsat Collection 2 Level 2 archives by using in situ temperature data. Results Results indicate that surface water temperatures in Henrys Lake during July–October have significantly increased (0.11–0.15°C per year), with the fastest rate of change observed in July (0.15°C per year). We did not detect a change in surface water temperature for May and June. These findings are consistent with broader trends in lake warming linked to climate change. Conclusions Increasing water temperatures are a potential stressor for Yellowstone Cutthroat Trout populations as they approach the thermal limits for survival, particularly when combined with competition from nonnative species, limited coldwater refugia, and the risk of harmful algal blooms. This study highlights the utility of satellite-based surface water temperature monitoring in assessing climate change impacts on freshwater ecosystems and emphasizes the need for ongoing water temperature monitoring to inform future conservation and management strategies for native fish species.