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High-frequency whistles of Irrawaddy dolphins (Orcaella brevirostris) recorded in Brunei Bay |
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| Authors: | Ying Jiang Zongwei Liu Chunmei Yang Lian-gang Lü Xiaolin Yu Longfei Huang Xuelei Zhang Zhiguo Yang Guangbing Yang Lu Sun Saifullah Arifin Jaaman Azmi Marzuki Muda |
| Affiliation: | 1. Key Laboratory of Marine Science and Numerical Modeling, First Institute of Oceanography, Ministry of Natural Resources, Qingdao, China;2. Key Laboratory of Marine Science and Numerical Modeling, First Institute of Oceanography, Ministry of Natural Resources, Qingdao, China Laboratory for Regional Oceanography and Numerical Modeling, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China;3. Key Laboratory of Science and Engineering for Marine Ecology and Environment, First Institute of Oceanography, Ministry of Natural Resources, Qingdao, China Laboratory for Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China;4. China National Deep Sea Center, Ministry of Natural Resources, Qingdao, China;5. Key Laboratory of Science and Engineering for Marine Ecology and Environment, First Institute of Oceanography, Ministry of Natural Resources, Qingdao, China;6. Institute of Oceanography and Environment, Universiti Malaysia Terengganu, Kuala Nerus, Terengganu, Malaysia |
| Abstract: | Studies of the whistles of Irrawaddy dolphins (Orcaella brevirostris) have traditionally been restricted to analyses of the human audio range (below 20 kHz). In this study, broadband acoustic recordings of Irrawaddy dolphins in Brunei Bay were obtained using a sampling frequency of 512 kHz. Among the 984 whistles collected, eight (0.81%) high-frequency whistles were detected with fundamentals above 18.4 kHz, which is the reported maximum frequency. Four (50%) of these whistles had the entire fundamentals in the ultrasonic frequency range (above 20 kHz), where 52.3 kHz was the maximum frequency. This is the first description of the ultrasonic components of Irrawaddy dolphin whistles. Our findings demonstrate that the whistles of Irrawaddy dolphins span a wider frequency range than previously published. |
| Keywords: | Brunei Bay high-frequency whistle Irrawaddy dolphin Orcaella brevirostris ultrasonic frequency range |