Native Fish Refuges of the Endangered Sonoyta River, Last Safeguard in the Sonoran Desert.

Authors: Nélida Acosta, Alejandro Romero, Angeles Cruz, Dennis Caldwell, Chuck Minckey, Doug Duncan

Year: 2025

Abstract

The Sonoyta pupfish (Cyprinodon eremus) and the longfin dace (Agosia chrysogaster), native species of the Sonoyta River, a binational basin between northwestern Mexico and the southwestern United States of America (USA), are in danger of extinction (PROY-NOM-059-SEMARNAT-2025 and IUCN Red List). For more than 25 years, a binational working group (BWG) has brought together experts from various institutions who developed an ex situ conservation strategy or refuges, where populations of both species are protected, with some refuges emulating the Sonoyta River habitats. The refuges aim to promote habitat diversity, which contributes to genetic variability, safeguarding the species due to their extirpation (local extinction) in their natural habitat. The BWG has dedicated technical, financial, and management resources to maintain and raise awareness about the loss of these freshwater species in the Sonoran Desert. Simultaneously, community outreach actions have been carried out to sensitize local inhabitants about the importance of these species, strengthening social participation in conservation. This effort represents the firm conviction of experts and institutions from the USA and Mexico to prevent the extinction of two native freshwater fish species and sets the course for resources to be secured in the coming years to sustain the project, including increasing the number of refuges and implementing the design of re-population programs in the natural habitat. This project is supported by: the NPS, the OPWR, the CPWR, the ASDM, the CONANP, the DICTUS, and the CEDO.