Spatial Models of Abundance and Habitat Preferences of Commerson?s and Peale?s Dolphin in Southern Patagonian Waters

DELLABIANCA, NATALIA; PIERCE GRAHAM J; ANDREA RAYA REY; GABRIELA SCIOSCIA; MILLER DAVID; TORRES, MÓNICA; PASO VIOLA, M.NATALIA; GOODDAL, R.NATALIE; ADRIÁN SCHIAVINI

PLOS ONE

PUBLIC LIBRARY SCIENCE

Lugar: San Francisco; Año: 2016 vol. 10

1932-6203

nterchange-newline">Commerson?s dolphins (Cephalorhynchus c. commersonii) and Peale?s dolphins (Lagenorhynchus australis) are two of the most common species of cetaceans in the coastal watersof southwest South Atlantic Ocean. Both species are listed as Data Deficient by the IUCN,mainly due to the lack of information about population sizes and trends. The goal of thisstudy was to build spatially explicit models for the abundance of both species in relation toenvironmental variables using data collected during eight scientific cruises along the Patagonian shelf. Spatial models were constructed using generalized additive models. In total,88 schools (212 individuals) of Commerson?s dolphin and 134 schools (465 individuals) ofPeale?s dolphin were recorded in 8,535 km surveyed. Commerson?s dolphin was found lessthan 60 km from shore; whereas Peale?s dolphins occurred over a wider range of distancesfrom the coast, the number of animals sighted usually being larger near or far from thecoast. Fitted models indicate overall abundances of approximately 22,000 Commerson?sdolphins and 20,000 Peale?s dolphins in the total area studied. This work provides the firstlarge-scale abundance estimate for Peale?s dolphin in the Atlantic Ocean and an update ofpopulation size for Commerson?s dolphin. Additionally, our results contribute to baselinedata on suitable habitat conditions for both species in southern Patagonia, which is essential for the implementation of adequate conservation measures