The source parameters of Irrawaddy dolphins’ echolocation click in the Bay of Brunei were estimated. Analysis of eight parameters shows that the Irrawaddy dolphins produce broadband echolocation clicks with mean click duration of 21.1 ± 7.2 μs. The clicks had a mean peak-to-peak apparent source level (ASL_pp) of 201.2 ± 7.3 dB re 1 μPa (N = 350), a mean peak frequency of 116.5 ± 15.2 kHz, a mean centroid frequency of 115.4 ± 13.9 kHz, − 3 dB bandwidth of 51.8 ± 17.7 kHz, and − 10 dB bandwidth of 100.9 ± 20.3 kHz. Foraging behaviour was characterized by the high movement of the animals in various directions with no obvious pattern and frequent deep dives. The source parameters of the Brunei Bay Irrawaddy dolphins’ clicks from the present study were compared to those of the populations in Bangladesh and Thailand. The apparent source level and frequency range of clicks for the population in Brunei Bay were wider than those of the population in Bangladesh and Thailand. The variations in the measured parameters might be due to environmental factors or behaviour related.

估算了文莱湾伊洛瓦底江海豚回声定位的声源参数。对八个参数的分析表明，伊洛瓦底江海豚产生了宽带回声定位滴答声，平均滴答持续时间为21.1±7.2μs。咔嗒声的平均峰峰值视在声源电平（ASL _pp）为201.2±7.3 dB re 1μPa（N = 350），平均峰值频率116.5±15.2 kHz，平均质心频率115.4±13.9 kHz，− 3 dB带宽51.8±17.7 kHz和− 10 dB带宽100.9±20.3 kHz。觅食行为的特征是动物在各个方向上的高运动性，没有明显的规律，并且频繁下潜。本研究将文莱湾伊洛瓦底江海豚点击的声源参数与孟加拉国和泰国人群的声源参数进行了比较。文莱湾人口的表观声源水平和点击频率范围比孟加拉国和泰国的人口要宽。测量参数的变化可能是由于环境因素或与行为有关的。