MARINE MAMMAL SCIENCE, **(*): ***–*** (*** 2014) © 2014 Society for Marine Mammalogy DOI: 10.1111/mms.12194 Pulsed signal properties of free-ranging bottlenose dolphins (Tursiops truncatus) in the central Mediterranean Sea GIUSEPPA BUSCAINO, 1 GASPARE BUFFA, FRANCESCO FILICIOTTO, VINCENZO MACCAR- RONE, VINCENZO DI STEFANO, MARIA CERAULO, and SALVATORE MAZZOLA, CNR, Istituto per l’Ambiente Marino Costiero UOS Capo Granitola, BioacousticsLab, Via del Faro No. 3, 91021–Torretta Granitola (TP), Italy; GIUSEPPE ALONGE, ENEA, UTMEATER, Via Catania No. 2, Palermo, Italy. Abstract This study describes pulsed signals from bottlenose dolphins of the central Medi- terranean Sea. Data were collected during 2011 and 2012 in 27 surveys in the Sicil- ian Channel, during which 163 animals were sighted. Based mainly on the pulse repetition rate, the signals were classified as Low-frequency click (LF; single clicks without a regular pulse rate), Train click (TC; with a interclick interval of 80 Æ 2 ms), Burst (with a interclick interval of 3.4 Æ 0.2 ms), or Packed click (with a lower number of clicks per train and median interclick interval of 3.2 Æ 0.0 ms). The measured parameters were peak sound pressure level (SPL pk ); signal duration; the 1st, 2nd, and 3rd peak of frequency; number of peaks frequency; bandwidth; centroid frequency; and the 10th, 25th, 75th, and 90th percentiles of the power spectrum distribution. Most of the parameters were significantly different among the groups, reflecting the different functions of these signals. LF clicks showed a lower peak frequency and percentiles and a longer duration and could be used to explore a wide area without a specific target focalization and with less resolution. The TC showed a higher SPL pk , higher peak frequency, lower duration, and lower number of secondary peaks frequency, showing a better resolution to investigate a specific target. Key words: bottlenose dolphin, Tursiops truncatus, pulsed signals, Mediterranean Sea. Bottlenose dolphins, like other dolphins, produce pulsed acoustic emissions that vary widely in duration, interpulse interval, and spectral composition (Au 1993, Houser et al. 1999). These pulsed signals are usually categorized as echolo- cation clicks and burst clicks. Echolocation clicks are used for detection, ranging, and discrimination of objects by trained dolphins (Au 1993) and likely in free- ranging animals (Simard et al. 2010). Burst clicks, similar to echolocation clicks but with a higher pulse rate, are used in association with social interaction for short-distance communicative purposes (Caldwell and Caldwell 1967, Lammers et al. 2003). 1 Corresponding author (e-mail: giuseppa.buscaino@cnr.it). 1