Bringing back to nature three extinct in the wild pupfish species (Cyprinodon alvarezi, C. longidorsalis and C. veronicae) from Nuevo León, México .

Authors: John Ewen, Alex Cliffe, Omar Domínguez, Brian Zimmerman, Juan Martínez, Maria Martínez, Erick Oñate-González, Craig Pelke, Anton Weissenbacher, Perla Alonso-Eguíalis, Landy Orozco-Uribe, Axel Moehrenschlager, Federico Hernández, Ricardo Munguía, Topiltzin Contreras-MacBeath

Year: 2025

Abstract

For the last 30 years three Extinct in the Wild Mexican pupfish species (Cyprinodon alvarezi, C. longidorsalis and C. veronicae) have existed in precariously small numbers, cared for in a small number of dedicated ex situ facilities including zoos and aquariums, outside of México. These three species, once occurred in relatively close proximity in the Nuevo León State in México, in small spring habitats, and suffered the similar threats that resulted in their extinction from the wild by the early- to mid-1990s. Following the species conservation cycle implemented by the IUCN/SSC in recent years, efforts in Mexico to address the freshwater fish extinction crisis have intensified, including the development of action plans aimed at critically endangered species as well as the development of strategies for the return of species kept in captivity to the wild. It is within this framework that this proposal is developed, which seeks to revitalize the ex situ populations of each species to guard against extinction, to establish ex situ populations in Mexico, as well as provide numbers of pupfish for upcoming planned releases over the next five years, establishing the first wild populations for each species in nearly three decades. As part of the activities carried out to date, captive populations have increased and new populations have been established in other aquariums such as Bristol Zoo and Vienna. A facility has also been established at the Inbursa Aquarium in Mexico City for the maintenance and reproduction of these species in Mexico and we are awaiting permits for their importation. A hydrogeological and hydrological evaluation was also carried out to see the feasibility of recovering the water flows necessary for habitat restoration. To this end, Environmental Systems (HS) were defined that delimit each spring of interest, the behavior of the system was analyzed through hydrography, geological units, aquifers, climatology (historical records of 40 years) and elaboration of hydrological balances. Based on this information, participatory planning work has been carried out with the ejidos of the region to establish the necessary agreements for the reintroduction of the species. Preliminary results show that there is the possibility of establishing populations in situ, in addition to working on the maintenance and recovery of some flows, but the most important thing has been the positive response of the ejidos, as well as their interest in the return of the species that were once part of their natural heritage and that the elderly people of the community still remember. We are clear that there is still a lot to do before we are able to return these species to the wild, but we believe that we will be able to reach our goal of recovering some in the next five years.