An Analysis of Fish Assemblages and Flow Regimes Upstream and Downstream of Falcon Reservoir

Author

Christopher J. Austin, The University of Texas Rio Grande Valley

Date of Award

8-1-2024

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Biology

First Advisor

Christopher Taylor

Second Advisor

Frank Dirrigl

Third Advisor

Hudson DeYoe

Abstract

The lower Rio Grande is regulated by Falcon and Amistad dams. Native fish species rely on the natural flow regime for habitat and spawning. I analyzed streamflow discharge and fish assemblages above and below Falcon Reservoir to assess potential impacts of dam impoundment. Fish collections were conducted by seine, and river discharge data was provided by the International Boundaries and Water Commission. I found significant differences in fish assemblages above vs below Falcon Reservoir, and the flow regime was significantly more altered downstream of Falcon Reservoir. I also identified two Species of Greatest Concern for Texas above Falcon Reservoir (Notropis braytoni and Macrhybopsis aestivalis). Although the entire river below the upstream-most dam (Amistad) had considerable hydrologic alteration, the reach between Amistad and Falcon reservoirs retains important biodiversity in need of protection. Further research on the ecological and conservation implications of these findings is warranted to inform management and conservation efforts in the Rio Grande.

Comments

Copyright 2024 Christopher J. Austin. https://proquest.com/docview/3116502536

Recommended Citation

Austin, Christopher J., "An Analysis of Fish Assemblages and Flow Regimes Upstream and Downstream of Falcon Reservoir" (2024). Theses and Dissertations. 1540.
https://scholarworks.utrgv.edu/etd/1540