Population status of the desert pupfish (Cyprinodon macularius) in wetlands of the Reserva de la Biosfera Alto Golfo de California y Delta del Río Colorado

Authors: Martha Román-Rodríguez, María Valdez-García, Alejandra Calvo-Fonseca, Gorgonio Campos, Alejandro Varela-Romero

Year: 2017 (xlix)

Abstract

As part of the Protected Natural Areas Management Program, the Biological Monitoring Program of the desert pupfish (Cyprinodon macularius) was developed with the purpose of strengthening the conservation of this priority species for the Upper Gulf of California and Colorado River Delta Biosphere Reserve, by assessing their populations, current distribution, habitat conditions, threat determination, and conservation opportunities To accomplish this objective, systematic sampling was carried out from August to November 2016 in 10 different localities of the Ciénega de Santa Clara and El Doctor wetlands Sampling of the fish was carried out using minnow traps with a dwell time in the water of 6 to 24 hours, after which a review and in-situ processing of the specimens of pupfish return them alive at the capture site The by catch fauna was collected for further processing To perform the physicochemical evaluation of the habitat were recorded the variables of temperature, salinity, dissolved oxygen and pH in each of the collection sites The pupfish was present in 4 of the 10 sampled localities, La Palma, Los Pinos and Espejo de Luna in the springs of El Doctor and one more in the Flor de Desierto-Cienega de Santa Clara The most abundant species during the sampling period was the exotic fish Poecilia latipinna (4069%) vs 2193% of the pupfish fish Only in one locality (Flor del Desierto) pupfish was the dominant species (83%) The average size of the pupfish was 31 cm of total length, the proportion between males and females was 1: 22 The growth in C macularius is allometric positive W=00276L27, the highest condition factor (3046) was obtained for individuals captured in the locality Flor del Desierto and generally higher during the summer months It was confirmed as cited in previous studies that the distribution and abundance of pupfish maintains fluctuations in the sampling area that depend on the dynamics of the hydrological system of the sites for the permanence of marginal areas of flood as an ideal habitat for C macularius Degradation of habitat by anthropogenic activities and the invasion of exotic fish species, especial, continue to be the main threat to the permanence of pupfish in the wetlands of the Reserve It is advisable to initiate a Recovery Plan of the species as well as eradication of exotic species as well as creation of refuges into the Reserve wetlands in order to promote and ensure the permanence of the species in the Colorado River Delta