Spinner dolphins (Stenella longirostris GRAY, 1828) acoustic parameters recorded in the Western South Atlantic Ocean

• DOI: 10.1121/1.4899440
• Publication Date: 2014-10-18T00:33:39Z
• Authors: Juliana R. Moron; Artur Andriolo; Marcos Rossi-Santos
• Keywords: 0402 animal and dairy science; 04 agricultural and veterinary sciences; 14. Life underwater

Spinner dolphins bioacoustics were study only in Fernando de Noronha Archipelago region in the Western South Atlantic Ocean. Our study aimed to describe the acoustic parameters of this species recorded approximately 3500 km south of Fernando de Noronha Archipelago. An one-element hydrophone was towed 250 m behind the vessel R/V Atlântico Sul over the continental shelf break. Continuous mono recording was performed with the hydrophone passing signals to a digital Fostex® FR-2 LE, recording at 96 kHz/24 bits. A group of approximate 400 dolphins were recorded on June 3, 2013, at 168.9 km shore distance (27o 24’29”S, 46o50’05”W). The wav-files were analyzed through the spectrogram configured as DFT 512 samples, 50% overlap and Hamming window of 1024 points generated by software Raven Pro 1.4. The preliminary results of 10 min recording allowed the extraction of 693 whistles that were classified in contours shapes as: upsweep (42%), chirp (17.3%), downsweep (14%), sinusoidal (10.5%), convex (5.9%), constant (5.4%), and concave (4.9%). Minimum frequencies ranged from 3.32 kHz to 23.30 kHz (mean = 10.88 kHz); maximum frequencies ranged from 6.61 kHz to 35.34 kHz (mean = 15.77 kHz); whistle duration ranged from 0.03 s to 2.58 s (mean = 0.68 s). These results are important to understand populations and/or species distributed in different ocean basins.