Ecological niche modeling of Stenella dolphins (Cetartiodactyla: Delphinidae) in the southwestern Atlantic Ocean

Abstract

Since the Moreno's et al. (2005) work, no study was done to update the distribution patterns of Stenella dolphins in the southwestern Atlantic Ocean. Ecological niche modeling was used to redefine the distribution patterns of Stenella dolphins in this area of Atlantic Ocean. Maximum entropy method (Maxent) was employed to generate models using a set of environmental variables as explanatory variables of the location records obtained by sighting and accidental captures. All ecological niche models performed returned AUC values >0.9. Areas with high environmental suitability for pantropical spotted dolphin (Stenella attenuata), Clymene dolphin (Stenella clymene) and spinner dolphins (Stenella longirostris) are found in warm (>25°C) and deep waters (≥1000m). High environmental suitability for Atlantic spotted dolphin (Stenella frontalis) seems to occur between 20.5°S and 30°S in the southeastern Brazilian coastal waters. The projected maps of species distributions showed patterns closely related to environmental changes at a fine spatial scale and added valuable information about the offshore limits of those oceanic species. The results suggest that the different species of Stenella have distinct environmental requirements in the southwestern Atlantic Ocean.