Population ecology of Crocodylus acutus in the estuarine systems of San Bias, Nayarit, Mexico [Ecología poblacional de Crocodylus acutus en los sistemas estuarinos de San Bias, Nayarit, México]

This study was conducted in San Bias estuaries during June 2005 and February 2006 (dry season) and October 2005 and October 2007 (rainy season). The purpose was to describe the population of crocodiles according to its distribution and abundance. Spotlight surveys counting animals found per kilometer were done navigating 89 kilometers in 6 transects. Transects A, B and C had a density from 2.68 to 4.31 crocodiles/kilometer or 0.05 crocodiles/ha, with 26 active nests, 6 different types of vegetation and salinity from 11.03%o in dry season to 4.92%o in rainy season. Transects D, E and F had a density from 0.014 to 0.36 crocodiles/km or 0.002 crocodiles/ha, any nest was found, 1 single type of vegetation and salinity from 35.85%o in dry season to 24.56%o in rainy season. Statistical similarity in transects A, B and C was 80%, in transects D and E was 70% and in transect F was 10%. Crocodile population was estimated in 333 crocodiles and all sizes were represented. The habitat in San Bias estuaries allows Crocodylus acutus develop properly its biological cycle