Assessing Response Diversity of Spawning Conditions for Native Trout Among Streams to Interannual Changes in Snowpack

Author

• Autumn Kaye Zierenberg, Utah State University

Date of Award

12-2025

Degree Type

Thesis

Degree Name

Departmental Honors

Department

Watershed Sciences

Abstract

Stream habitat suitability for fish is controlled by physical, chemical and biological conditions impacted by interannual changes in climate. Intermittent streams are particularly sensitive to climatic variation and have long been overlooked as potential spawning habitats for fish and other riverine species. Spawning suitability in stream habitats is strongly influenced by connectivity to perennial habitats, the duration of surface flows and water temperatures, each of which are driven by annual snowpack and discharge conditions. Here, we examine how the spawning habitat suitability in different tributaries within a single river basin respond to changes in annual snowpack conditions. Specifically, we examined the mosaic of tributary spawning opportunities available to the Bear River Cutthroat Trout (Oncorhynchus virginalis ssp.) in northern Utah’s Logan River basin. We collected water temperature and surface flow presence data from 20-23 tributaries across three years corresponding to low (2022), high (2023), and intermediate (2024) snowpack conditions. We calculated the duration of suitable spawning windows within each tributary as the number of days with surface flows in which a spawner could lay eggs and have them accumulate enough thermal degree days to emerge before stream drying or the end of the growing season. We found spawning window duration to vary considerably between years and tributaries, and importantly, we found streams to demonstrate diverse responses to the shared climatic changes. Specifically, intermediate elevation intermittent streams demonstrated positive responses to increased snowpack, while perennial streams demonstrated negative responses to increased snowpack. This response diversity stabilizes tributary spawning opportunities at the basin-scale to high interannual variability within any given tributary habitat, as long as trout can access the diversity of tributary habitats. Understanding how changing snowpack conditions are likely to influence the distribution of suitable spawning habitats is important for informing future O. virginalis spp. conservation efforts, as climate change is expected to reduce annual snowpack in the region. Our results highlight the importance of maintaining or re-establishing access to diverse tributary habitats to allow populations to cope with spatiotemporally varying conditions.

Recommended Citation

Zierenberg, Autumn Kaye, "Assessing Response Diversity of Spawning Conditions for Native Trout Among Streams to Interannual Changes in Snowpack" (2025). Undergraduate Honors Capstone Projects. 1088.
https://digitalcommons.usu.edu/honors/1088