Passive acoustics has been used extensively to study bottlenose dolphins; yet very few studies have examined the spatial, temporal, and environmental influences on vocalization types (echolocation, burst pulse sounds, and whistles), and few are long-term and provide high temporal resolution over multiple years. We used data from 2013 to 2018 to establish baseline acoustic patterns for bottlenose dolphins in the May River estuary, South Carolina. We deployed acoustic recorders at six stations during 2013–2014 and three stations during 2015–2018, with locations spanning the entire estuary (headwaters to the mouth). We discovered that acoustic detection of dolphins varied not only spatially, but also yearly, monthly, and tidally. Higher numbers of echolocation bouts, burst pulse sounds, and whistles were detected at the mouth as compared to the headwaters. At the mouth, vocalization detections were greatest in fall and winter for multiple years, and echolocation detection was greatest during falling and low tides. This study provides an example of another tool, long-term passive acoustics monitoring, to better understand spatial and temporal distribution of dolphins in a typical salt marsh estuary, that can be applied to other ecosystems throughout the southeastern United States and globally.

中文翻译：

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评估南卡罗来纳州梅河河口大西洋普通宽吻海豚 (Tursiops truncatus) 时空发声模式的长期被动声学

被动声学已被广泛用于研究宽吻海豚。然而，很少有研究检查空间、时间和环境对发声类型（回声定位、脉冲脉冲声和口哨声）的影响，而且很少有研究是长期的，并且提供多年的高时间分辨率。我们使用 2013 年至 2018 年的数据来建立南卡罗来纳州梅河河口宽吻海豚的基线声学模式。我们在 2013-2014 年期间在六个站点部署了录音机，在 2015-2018 年期间部署了三个站点，其位置跨越整个河口（源头到河口）。我们发现海豚的声学探测不仅在空间上发生变化，而且在每年、每月和潮汐上都有所不同。更高数量的回声定位、突发脉冲声音、与源头相比，在口中检测到口哨声。在口部，多年来的秋季和冬季发声检测最大，回声定位检测在下降和退潮期间最大。这项研究提供了另一个工具的例子，长期被动声学监测，以更好地了解典型盐沼河口中海豚的时空分布，可应用于美国东南部和全球的其他生态系统。