Living in an estuary: Commerson´s dolphins habitat use and behavioural pattern at the Santa Cruz river, Patagonia, Argentina

Commerson's dolphins, Cephalorhynchus commersonii , suffer bycatch in fisheries and are target of dolphin-watching activities along Patagonia. Here we described dolphins' habitat use and behavioural patterns at the estuary of Santa Cruz River. Behavioural observations were made from vantage points using a spotting scope. Additionally we analyzed the habitat use dividing the survey area into 1 km 2 cells and characterized with depth and benthic slope. Habitat use models indicated that dolphins prefer shallow water inside the estuary. Additionally, a new behavioural context was assigned to diving , an already described behaviour for the species. This behaviour showed a high frequency during downing tide, suggesting a benthic foraging strategy.