Abstract:

Based on the 113-day acoustic data measured in the Beibu Gulf, this paper uses an automatic detection method to detect the click signals of cetaceans in the data, counts the number of signals, and obtains the vocalization patterns of cetaceans during the observation period. Statistical analysis of the number of click signals of cetaceans during the observation period shows that the number of clicks of cetaceans is less in late winter and more in early spring. During the day, it is less and at night, it is more. The influence of hydrological and meteorological factors on the number of click signals of cetaceans during the observation period is analyzed. It is found that the number of click signals of cetaceans is less in late winter and more in early spring. The correlation between sea surface temperature, wind speed, and rain fall and the number of click signals of cetaceans is not obvious, the low-frequency environmental noise is calculated, and it is found that the noise level is high during the day and low at night, which is inversely proportional to the number of click signals of cetaceans during the day and night. This is considered to be caused by the difference in ship noise between day and night. The situation of ship noise during the observation period is analyzed, and it is found that cetaceans’ click signals are affected by ships. When ship noise occurs, cetaceans do not vocalize or have fewer vocalizations. Thus, it is concluded that cetaceans have a certain avoidance phenomenon towards ships.

Key words: Cetaceans, Click signals, Frequency of vocalization, Influencing factors

摘要：

鲸豚类动物的水下发声往往受到环境因素的影响，国内相关研究较少，且多集中于近岸。本文基于北部湾离岸约100 km位点实测的声学数据，自动检测鲸豚类动物回声定位信号，研究鲸豚类动物的发声规律以及环境因子与低频噪声的影响。2023年1月13日至5月5日连续记录113 d，获取152 550个声音文件，经检测其中37 d记录到鲸豚类动物回声定位信号，共计74 180个。回声定位信号的发声次数在冬末较少、初春较多，白天较少、夜晚较多。通过计算低频段环境噪声，发现白天噪声级高、夜晚噪声级低，与鲸豚类动物昼夜发声次数成反比，同时发现当船舶噪声出现时，鲸豚类动物不发声或发声次数少，由此可知鲸豚类动物对船舶具有一定的规避现象。进一步分析发现，海水表层温度、风速、降雨量因素与鲸豚类动物发声次数之间无明显相关性。

关键词: 鲸豚类动物, 回声定位信号, 发声次数, 影响因素