Abstract

VALDES-ARELLANES, Michelle P. et al. Abundance of two populations of bottlenose dolphins (Tursiops truncatus) in northern Veracruz, Mexico. Rev. Mex. Biodiv. [online]. 2011, vol.82, n.1, pp.227-235. ISSN 2007-8706.

In Mexico, the population size of the bottlenose dolphin (Tursiops truncatus) is unknown, due to the fact that they are highly mobile, and occasionally there are exchanges of individuals between populations. The objective of this study was to determine the abundance of dolphins in the north of Veracruz. From March 2005 to December 2007 were 50 surveys with a total effort of 236.7 hours. The results of the photo-identification of dolphins were used in the Jolly-Seber model, and with this model we estimated a total of N = 302 ± 113 dolphins throughout the study area. For Tamiahua a population estimate of N = 177 ± 10 dolphins, and for Tuxpan N = 161 ± 68 dolphins. These results suggest that there is minimal exchange of dolphins between areas; therefore it is assumed that populations are not isolated but dolphins have a preference for certain areas, and confirms that there is fidelity to the site of 13 years from the photo-recapture of some individuals in the area of Tamiahua. The fidelity may be a consequence of the high primary productivity present in the area, therefore is an ideal place for breeding and shelter.

Keywords : photo identification; Gulf of Mexico; Jolly-Seber; effort; site fidelity; exchange.

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