Differences in oscillatory whistles produced by spinner (Stenella longirostris) and pantropical spotted (Stenella attenuata) dolphins |
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Authors: | Pina Gruden Paul R. White Julie N. Oswald Yvonne Barkley Salvatore Cerchio Marc Lammers Simone Baumann‐Pickering |
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Affiliation: | 1. Institute of Sound and Vibration Research, University of Southampton, Highfield, United Kingdom;2. Bio‐Waves Inc., Encinitas, California, U.S.A;3. NOAA Pacific Islands Fisheries Science Center, Honolulu, Hawaii, U.S.A;4. New England Aquarium, Boston, Massachusetts, U.S.A;5. Hawaii Institute of Marine Biology, Kane'ohe, Hawaii, U.S.A;6. Scripps Institution of Oceanography, University of California San Diego, La Jolla, California, U.S.A |
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Abstract: | Acoustic recordings of two closely related species, spinner dolphin (Stenella longirostris) and pantropical spotted dolphin (Stenella attenuata), were investigated from four different geographic locations: two in the Central Tropical Pacific, one in the Eastern Tropical Pacific and one in the Indian Ocean. The two delphinid species occur in tropical and warm temperate waters, with overlapping ranges. They produce very similar vocalizations, but at the same time their calls exhibit a certain degree of intraspecific variation among different geographic locations as has been observed in other delphinid species. Oscillatory whistles (whistles with at least two oscillations in their frequency contours) were identified and manually extracted from the recordings. Whistles with four or more maxima (oscillations) occurred only in spinner dolphins and they were present in all geographic regions investigated. In addition, the oscillatory whistles with two and three maxima were significantly more frequent in spinner than in spotted dolphins. The differences in oscillatory whistles for these two species seem to be consistent across study areas and therefore, could be used in addition to other whistle features to help distinguish between them. |
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Keywords: | oscillatory whistles whistle global features decision rule dolphin spinner dolphin pantropical spotted dolphin Stenella longirostris Stenella attenuata towed hydrophone array |
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