In this study, echolocation signals were recorded from a wild Irrawaddy dolphin(Orcaella brevirostris) in shallow water in the Bay of Brunei. During sound recording, a small fishing boat engine startled a nearby Irraw...In this study, echolocation signals were recorded from a wild Irrawaddy dolphin(Orcaella brevirostris) in shallow water in the Bay of Brunei. During sound recording, a small fishing boat engine startled a nearby Irrawaddy dolphin and began chasing it on two occasions. Variations in the acoustic parameters were detected. When the Irrawaddy dolphin was startled and chased, the sound pressure level, number of click trains per minute, pulse number, and average inter-pulse interval(PI) per click train were all affected. The PI increased and exhibited a slight downward trend during the chase. The increase in PI indicated an increase in the inspection distance as the dolphin escaped. Thus, Irrawaddy dolphins may adapt their echolocation signals to stand out from ambient noise in the wild and to improve their search efforts in potentially risky situations. Appropriate management of the burst noise around the dolphins is important.展开更多
基金The National Key R&D Program of China under contract No.2017YFC1405100the Key Laboratory of Marine Ecology and Environmental Science and Engineering,Ministry of Natural Resources under contract No.MESE-2016-05+1 种基金the National Natural Science Foundation of China-Shandong Joint Fund for Marine Ecology and Environmental Sciences under contract No.U1406403the China-ASEAN Maritime Cooperation Fund
文摘In this study, echolocation signals were recorded from a wild Irrawaddy dolphin(Orcaella brevirostris) in shallow water in the Bay of Brunei. During sound recording, a small fishing boat engine startled a nearby Irrawaddy dolphin and began chasing it on two occasions. Variations in the acoustic parameters were detected. When the Irrawaddy dolphin was startled and chased, the sound pressure level, number of click trains per minute, pulse number, and average inter-pulse interval(PI) per click train were all affected. The PI increased and exhibited a slight downward trend during the chase. The increase in PI indicated an increase in the inspection distance as the dolphin escaped. Thus, Irrawaddy dolphins may adapt their echolocation signals to stand out from ambient noise in the wild and to improve their search efforts in potentially risky situations. Appropriate management of the burst noise around the dolphins is important.
