Estimación poblacional del cocodrilo americano (Crocodylus acutus) en el Parque Nacional Lagunas de Chacahua, Oaxaca, México

This study was conducted from November 2013 to June 2014 with the aim of estimating the population of American crocodile (Crocodylus acutus) in the Lagunas de Chacahua National Park (PNLCh). The field work consisted in surveys during three consecutive nights each month on several localities. The recorded encounter rates (ER) obtained by transect lines ranged from 2.3 (Zapotalito) to 33.4 (Palmarito) ind/km. The locality Palmarito showed the most representative population structure, while Zapotalito presented the lowest percentage of sightings. Significant differences were found per month in the abundance with age class respect to the frequency of crocodile use of the environments, as well as a significant interaction between month, habitat and age class. The total population estimated by transect lines fluctuated between 2.8 and 47.9 individuals. The greater abundance of individuals occurred in Palmarito (47.9 ± 0.4 individuals), while the lowest was found in Zapotalito (2.8 ± 0.3 individuals). The first approximations on population ecology and the current status of the American crocodile in the PNLCh are provided in this research and represent the basis of population monitoring in future years for the administration of this Mexican protected site.