CONICET | Buscador de Institutos y Recursos Humanos

Several species of small cetacean inhabit the coastal area of Patagonia (Argentina), but little is known about their distribution and the overlap degree between them. The goal of this work is to build habitat selection models for small cetaceans in order to assess areas of particular importance for the different species. These models were constructed using physiographic and remotely-sensed variables. Thirteen aerial surveys were conducted along the Patagonian coast (from Golfo San Matías, 40º40´-42º14´S-65º00´-63º47´W to Bahía de los Nodales, 48º00´S-65º35´W) from 1994 to 2007. A grid of 0.5ºx0.5º cells was constructed for the study area. Each cell was characterized by environmental variables and by the encounter rate (ER) for each species of cetacean. ER of each species were investigated in relation to environmental variables using generalized linear models and a model averaging (multimodel-inference) was used to obtain predicted ER for different species. A correlation between ER of different species was analyzed by Spearman correlation. The environmental variables that were found significant predictors of the species distribution differed between species. The ERs of dusky dolphin (Lagenorhynchus obscurus) and Peale´s dolphins (Lagenorhynchus australis) showed a positive relationship. Commerson´s dolphin (Cephalorhynchus commersonii) presented a more coastal distribution than the other species, and individuals are more often found feeding in estuaries zones. Knowledge of the patterns distribution of small cetacean in the Patagonian coast provides baseline knowledge of how these species interact with each other and their environment. Such information should be considered when potential areas of conflict between coastal small cetaceans and human activities will be determined.

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