Acoustic encounters of killer and beaked whales during the 2014 SORP cruise

TRICKEY JENNIFER; REYES REYES MARIA VANESA; BAUMANN-PICKERING SIMONE; MELCÓN MARIANA; HILDEBRAND JOHN; IÑÍGUEZ MIGUEL

San Diego

Congreso; International Whaling Commission Scientific Committee meeting; 2015

International Whaling Commission

At least four different killer whale morphotypes and five species of beaked whales are known to occur in the Southern Ocean. In this paper we describe a subset of Antarctic killer whale signals and two echolocation signal types likely produced by beaked whales. Two types of killer whale echolocation clicks were recorded, with peak frequencies at 7.8 and 19.5 kHz, durations of 186 and 68 s, and interpulse intervals (IPIs) of 4 and 800 ms, respectively. An unknown killer whale morphotype produced high frequency modulated (HFM) signals, similar to those recently described for other populations. These signals were frequency down-swept with peak frequency at 18.2 kHz and mean duration 140.7 ms, and had more similar structure to the HFM signals recorded from North Pacific killer whales than to those reported in the North Atlantic. Two unknown beaked whale FM pulse types were recorded (Antarctic BW29 and BW37). BW29 was the dominant type encountered, with peak frequency at 28.7 kHz, pulse duration 600 μs, and IPI of 400 ms. BW37 had a higher peak frequency (36.7 kHz) and shorter IPI (120 ms). Based on a size-frequency relationship, it is possible that the southern bottlenose whale produces the BW29 pulse type, whereas the BW37 pulse type belongs to the smaller Gray?s beaked whale. Alternatively, it is possible that a single beaked whale species produced both signal types.