Genetic identification and reiterated captures suggest that the <i>Astyanax mexicanus</i> El Pachón cavefish population is closed and declining
Laurent Legendre, Université Paris-Saclay, CNRS, IRD, UMR Évolution, Génomes, Comportement et Écologie, Gif-sur-Yvette 91190, France, J. Rode, Isabelle Germon, Marie Pavie, Carla Quiviger, Maxime Policarpo, Julien Leclercq, Stéphane Père, Julien Fumey, Carole Hyacinthe, Patricia Ornelas-García, Luis Espinasa, Sylvie Rétaux, Didier Casañe, Objectif Sciences International NGO, OSI-Panthera Program, Geneva 99140, Switzerland, Institut de Neuroscience Paris-Saclay, Université Paris-Saclay and CNRS, Saclay 91400, France, Institut Pasteur, Université Paris Cité, Bioinformatics and Biostatistics Hub, Paris 75015, France, Colección Nacional de Peces, Departamento de Zoología, Instituto de Biología, Universidad Nacional Autónoma de México, México DF CP 04510, México, Université Paris Cité, UFR Sciences du Vivant, Paris 75013, France
Abstract
blind cavefish populations of North-East Mexico are demographic parameters of great importance for investigating a variety of ecological, evolutionary, and conservation issues. However, few estimates have been obtained. For these mobile animals living in an environment difficult to explore as a whole, methods based on capture-mark-recapture are appropriate, but their feasibility and interpretation of results depend on several assumptions that must be carefully examined. Here, we provide evidence that minimally invasive genetic identification from captures at different time intervals (three days and three years) can give insights into cavefish population size dynamics as well as other important demographic parameters of interest. We also provide tools to calibrate sampling and genotyping efforts necessary to reach a given level of precision. Our results suggest that the El Pachón cave population is currently very small, of an order of magnitude of a few hundreds of individuals, and is distributed in a relatively isolated area. The probable decline in population size in the El Pachón cave since the last census in 1971 raises serious conservation issues.