Abstract

GUEVARA-AGUIRRE, Daniel  and  GALLO-REYNOSO, Juan Pablo. Habitat use of two ecotypes of Bottlenose dolphins (Tursiops truncatus) in the Gulf of California, Mexico. Rev. Mex. Biodiv. [online]. 2016, vol.87, n.3, pp.1045-1054. ISSN 2007-8706.  https://doi.org/10.1016/j.rmb.2016.07.015.

Two ecotypes (coastal and oceanic) of bottlenose dolphins are described in the Gulf of California where the majority of the investigations have been done in coastal regions. This study analyzes if 10 environmental variables (depth, sea color, visibility, sea state, salinity, sea surface temperature, chlorophyll concentration, distance to coast, slope and water density) in Guaymas Basin could differentiate the habitat of both ecotypes, testing the hypothesis of local habitat. Thirteen surveys were conducted along the coastal area and 16 in the offshore area (September 2013-March 2014). Correspondence analysis showed that the coastal ecotype forages and transits in the morning, socializes at noon and rests in the evening, these behaviors were determined by 6 variables (sea surface temperature, visibility, salinity, sea color, distance to coast, and slope). The offshore ecotype forages in the morning and in the afternoon, has a social life at noon, rests in the evening and transits in the morning and afternoon, these behaviors are determined by 4 variables (depth, sea color, sea surface temperature, slope). Ecological niche models showed that 5 variables characterize and differentiate the ecotypes (slope, chlorophyll concentration, distance from the coast, sea state, and sea color). The local habitat hypothesis is proven as each ecotype depends on the cluster of variables of their habitat.

Keywords : Ecological niche; Generalized linear model; Correspondence analysis.

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