Knowledge of cetacean occurrence and behaviour in southern African waters is limited, and passive acoustic monitoring has the potential to address this gap efficiently. Seasonal acoustic occurrence and diel-vocalizing patterns of sperm whales in relation to environmental conditions are described here using passive acoustic monitoring data collected off the west coast of South Africa. Four autonomous acoustic recorders (AARs) were deployed on 3 oceanographic moorings from July 2014 to January 2017. Sperm whale clicks were detected year round in most recording sites, with peaks in acoustic occurrence in summer and late winter through spring. Dielvocalizing patterns were detected in winter, spring and summer. Higher percentages of sperm whale clicks were recorded by AARs deployed at 1100 m water depth compared to those concurrently deployed at 850 and 4500 m, likely inferring that the whales exhibited some preference to water depths around 1100 m. Acoustic propagation modelling suggested a maximum detection range of 83 km in winter for sperm whale clicks produced at 1100 m. Random forest models classified daylight regime, sea surface height anomaly and month of the year as the most important predictors of sperm whale acoustic occurrence. The continuous acoustic occurrence of sperm whales suggests that the study area supports large biomasses of prey to sustain this species’ food requirements year round. This is the first study to describe the seasonal acoustic occurrence and diel-vocalizing patterns of sperm whales off the west coast of South Africa, extending knowledge of the species previously available only through whaling records.

中文翻译：

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全年点击：抹香鲸点击与南非西海岸附近的环境条件有关

对南部非洲水域鲸类发生和行为的了解有限，被动声学监测有可能有效解决这一差距。此处使用从南非西海岸收集的被动声学监测数据描述了与环境条件相关的抹香鲸的季节性声学发生和日常发声模式。从 2014 年 7 月到 2017 年 1 月，在 3 个海洋系泊处部署了四个自主声学记录器 (AAR)。在大多数记录地点全年都检测到抹香鲸的咔嗒声，在夏季和冬末至春季的声学发生高峰期。在冬季、春季和夏季检测到双发声模式。与同时部署在 850 米和 4500 米处的 AAR 相比，部署在 1100 米水深的 AAR 记录的抹香鲸咔嗒声的百分比更高，这可能推断鲸鱼对 1100 米左右的水深表现出一些偏好。声学传播模型表明，冬季在 1100 米处产生的抹香鲸咔嗒声的最大探测范围为 83 公里。随机森林模型将日光状况、海面高度异常和一年中的月份分类为抹香鲸声学发生的最重要预测因素。抹香鲸的持续声响表明该研究区域支持大量的猎物来维持该物种全年的食物需求。这是第一项描述南非西海岸抹香鲸季节性声学发生和日常发声模式的研究，