1. The estuaries within the Pearl River Delta are sites for large‐scale urban development and offshore construction. These projects have conservation stakeholders calling for more protection for the Indo‐Pacific humpback dolphins whose habitat overlaps with current and proposed construction sites.
2. Efforts to improve impact assessments are hindered by the lack of baseline data and comprehensive understanding of how often the dolphins are present in areas near or within locations targeted for further development. The Modaomen Estuary within the Pearl River Delta is a good example of this, with little consideration for the dolphins as no data on their diurnal and seasonal occurrences within the estuary exist.
3. A passive acoustic monitoring system was deployed over a calendar year from October 2016 to September 2017 to monitor the presence of humpback dolphins in the Modaomen Estuary.
4. Results indicated that the estuary is an important area for humpback dolphins, with regular diel rhythms and seasonality in detection rates. For example, higher detections were seen during the wet season than during the dry season. However, there was no significant difference in detection rates between the flood and ebb tides, or between high and low tidal phases.
5. Since the Modaomen Estuary is targeted for further development in the near future, these data provide the rationale for resource management and consent processes to consider potential impacts on the dolphins, as well as to aid marine spatial planning and conservation measures.

中文翻译：

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在高度城市化的河口中监视印度太平洋驼背海豚的发生，为保护和管理提供信息

1. 珠江三角洲的河口是大规模城市发展和海上建设的场所。这些项目有保护利益相关者，他们呼吁对栖息地与现有和拟议建筑工地重叠的印度太平洋驼背海豚提供更多保护。
2. 缺乏基线数据和对海豚在有待进一步开发的地点附近或区域内出现的频率的全面理解的阻碍，阻碍了改进影响评估的努力。珠江三角洲的墨刀门河口就是一个很好的例子，因为没有海豚在昼夜和季节发生的数据，因此很少考虑海豚。
3. 从2016年10月到2017年9月的日历年中，部署了无源声学监视系统，以监视魔岛门河口中座头海豚的存在。
4. 结果表明，河口是座头海豚的重要区域，其规律的迪尔节律和检测率呈季节性变化。例如，在雨季比旱季检测到的检出率更高。但是，潮汐和退潮之间或高潮和低潮相之间的探测率没有显着差异。
5. 由于磨刀门河口的目标是在不久的将来进一步发展，因此这些数据为资源管理和同意过程提供了理论依据，以考虑对海豚的潜在影响以及帮助进行海洋空间规划和保护措施。