09/26/2026
At SoyUnison, with the support of the Arizona-Sonora Desert Museum, we are taking a major step forward by establishing Mexico's second refuge for the longfin dace (Agosia chrysogaster), a species protected under the NOM-059 standard. These specimens come from the last population collected from the Sonoyta River.
Together, we are preventing the extinction of this species from our beloved Sonoran Desert. Cedo Intercultural
Unison Drives Initiative for Refuge to Protect Sonoyta River Native Fish
The University of Sonora (Unison), through the Department of Scientific and Technological Research (DICTUS), is promoting the creation of a refuge to breed and protect native fish species from the Sonoyta River, whose populations face threats due to aquatic habitat loss, reported researcher Alejandro Varela Romero.
The academic, affiliated with DICTUS's Molecular Ecology and Vertebrate/Invertebrate laboratories, explained that the refuge will form part of a conservation site network, establishing backup populations across different locations to support the species' eventual recovery in the wild.
He noted that roughly half of Sonora’s 47 native freshwater fish species are listed under a protection category within the Mexican Official Norm (NOM).
Varela Romero attributed the destruction of aquatic habitats to drivers such as agricultural activities and declining water availability, both of which alter natural river dynamics.
"When we lose these aquatic habitats, we are genuinely undermining our future quality of life as a state, city, and region—and the fish suffer for it," he stated.
The researcher emphasized the vital need to preserve flowing rivers under conditions that sustain healthy vegetation and the diverse species dependent on these ecosystems.
A Refuge for Sonoyta River Species
The project’s initial phase focuses on the longfin dace (Pupo panza verde), native to the Sonoyta River basin along the Sonora–Arizona border.
Varela Romero recalled that the Intercultural Center for the Study of Deserts and Oceans (CEDO), based in Puerto Peñasco, has successfully developed artificial refuges for native species. These existing shelters will provide the founding stock to build DICTUS’s backup population.
"We are founding this new refuge here at the University of Sonora’s DICTUS facility—where I work—operating as an endangered fish breeding laboratory," he said.
The sanctuary is located adjacent to the Vertebrate and Invertebrate laboratories, between the Dentistry department and the campus pool, directly across from the DICTUS greenhouse.
Breeding and Genetic Monitoring
The university team has set up a 1,000-liter tank equipped with a water circulation system tailored to the longfin dace's breeding needs, the academic detailed.
He explained that the tank utilizes fine sand as a substrate, allowing the fish to build nests and lay eggs, after which juveniles are moved to a dedicated rearing area.
The initiative also incorporates genetic health monitoring to identify potential inbreeding issues and evaluate long-term population viability for future reintroduction into wild habitats, Varela Romero added.
The researcher highlighted that longfin dace require moving water to reproduce, making their presence a key bioindicator of aquatic health.
"They need running water, not just a puddle or a dammed pond. The water has to flow—that’s how they breed," he noted.
For the project's second stage, equipment and tanks are already in place to launch a breeding system for the Quitobaquito pupfish (Cachorrito del Sonoyta), the professor announced.
He described the pupfish as a small species under two inches long, endemic to the Sonoyta River, whose males display a striking metallic blue coloration during the spawning season.
Collaborative Conservation Efforts
Varela Romero shared that the project aims to integrate into a broader binational network of refuges across Mexico and the United States, utilizing distributed safeguard populations to maximize species conservation and recovery odds.
The research team includes Mayra González Félix, Martín Pérez Velázquez, José Luis Nieblas Larreta, Alexandre Gutiérrez Barragán, and Carlos Ballesteros Córdoba, alongside student researchers.
The initiative also collaborates with Cedo, Comisión de Ecología y Desarrollo Sustentable del Estado de Sonora (CEDES), Centro Ecologico del Estado de Sonora, The University of Arizona, and other institutions dedicated to biodiversity preservation.
