Cooperative Fish and Wildlife Research Units Program: Utah
Education, Research and Technical Assistance for Managing Our Natural Resources

Utah Project

BoR: Hydrologic controls on abundance and distribution of the endangered Rio Grande silvery minnow in the Middle Rio Grande

May 2018 - September 2021


Participating Agencies

  • Bureau of Recalmation
The Middle Rio Grande has experienced dramatic hydrologic and geomorphic changes over the past century, which have resulted in reduced range and abundance of the endangered Rio Grande silvery minnow.

Rio Grande Silvery Minnow have experienced dramatic reductions in range and abundance, ultimately being listed as endangered under the U.S. Endangered Species Act. Their range is currently restricted to the Middle Rio Grande in New Mexico, where habitat degradation and hydrologic alterations present continuing challenges to silvery minnow conservation. Water managers are tasked with meeting many different and sometimes competing objectives with a limited supply of water in the basin. In this project, we are examining the relationship between annual hydrologic conditions and silvery minnow productivity, and will ultimately use our model to examine the relative performance of alternative water management approaches in the basin. This project is a collaboration with researchers and managers across multiple agencies and stakeholder groups, including the U.S. Bureau of Reclamation, U.S. Fish and Wildlife Service, U.S. Army Corps of Engineers, Middle Rio Grande Conservancy District, and New Mexico Interstate Stream Commision. Using the model developed in this project will help managers determine how likely silvery minnow conservation goals are to be met under alternative management options, informing decisions to benefit this endangered species in the presence of great uncertainty.

Technical Publications Publication Date
Budy, P. and Walsworth, T.E. 2019. Review of the “Analytical framework for evaluating the proposed water management and maintenance actions on Rio Grande silvery minnow, southwestern willow flycatcher, and yellow-billed cuckoo and their critical habitats” with recommendations for future analytical considerations. USGS Utah Cooperative Fish and Wildlife Research Unit Report UCFWRU(1) 2019: 1-38. February 2019
Walsworth, T.E. and Budy, P. 2020. DRAFT: Hydrologic control on abundance and dsitribution of the endangered Rio Grande silvery minnow in the Middle Rio Grande. USGS Utah Cooperative Fish and Wildlife Research Unit Report. 2020: 1-35. January 2020
Presentations Presentation Date
Walsworth TE and Budy P. 2020. Hydrologic drivers of distribution and abundance of the extremely imperiled Rio Grande silvery minnow. Annual Meeting of the Utah Chapter American Fisheries Society. St. George, UT. February 25-27, 2020. February 2020
Walsworth TE and Budy P. 2020. Rio Grande silvery minnow hydrobiological analysis: draft results. U.S. Bureau of Reclamation. January 27. Albuquerque, NM. USBR, Albuquerque Office. January 2020
Walsworth TE and Budy P. 2019. Final Review of Rio Grande silvery minnow Hydrobiological Objectives (HBO) Analyses. U.S. Bureau of Reclamation. February 28. Albuquerque, NM. USBR, Albuquerque Office February 2019