Seasonal occurrence of southeast Pacific blue whale songs in southern Chile and the eastern tropical Pacific

Passive acoustic data were collected January 2012 to April 2013 at four sites in the Chiloense Ecoregion ( CER ) in southern Chile (≈43°S–44°S, 71°W–73°W) and 1996–2002 from one site in the eastern tropical Pacific ( ETP ) (8°S, 95°W). Automatic detectors were used to detect the two songs ( SEP 1 and SEP 2) described for southeast Pacific ( SEP ) blue whales. There was a strong seasonal pattern of occurrence of SEP songs in the CER from December...