WDC, Whale and Dolphin Conservation Australasia, PO Box 720, Port Adelaide Business Centre, South Australia, 5015, Australia.
Les Brussattes 1, 2904 Bressaucourt, Switzerland.
Mar Pollut Bull. 2022 Nov;184:114183. doi: 10.1016/j.marpolbul.2022.114183. Epub 2022 Oct 18.
Dredging is an excavation activity used worldwide in marine and freshwater environments to create, deepen, and maintain waterways, harbours, channels, locks, docks, berths, river entrances, and approaches to ports and boat ramps. However, dredging impacts on marine life, including marine mammals (cetaceans, pinnipeds, and sirenians), remain largely unknown. Here we quantified the effect of dredging operations in 2005 and 2019 on the occurrence of Indo-Pacific bottlenose dolphins (Tursiops aduncus) and long-nosed fur seals (Arctocephalus forsteri) in the Port River estuary, a highly urbanized estuary in Adelaide, South Australia. We applied generalised linear models to two long-term sighting datasets (dolphins: 1992-2020, fur seals: 2010-2020), to analyse changes in sighting rates as a function of dredging operations, season, rainfall, and sea surface temperature. We showed that the fluctuations in both dolphin and fur seal occurrences were not correlated with dredging operations, whereas sea surface temperature and season were stronger predictors of both species sighting rates (with seals more prevalent during the colder months, and dolphins in summer). Given the highly industrial environment of the Port River estuary, it is possible that animals in this area are habituated to high noise levels and therefore were not disturbed by dredging operations. Future research would benefit from analysing short-term effects of dredging operations on behaviour, movement patterns and habitat use to determine effects of possible habitat alteration caused by dredging.
疏浚是一种在海洋和淡水环境中广泛使用的挖掘活动，用于创建、加深和维护航道、港口、水道、水闸、码头、泊位、河流入口、港口和船坡道。然而，疏浚对海洋生物的影响，包括海洋哺乳动物（鲸目动物、鳍足类动物和海牛目动物），仍然知之甚少。在这里，我们量化了 2005 年和 2019 年疏浚作业对南澳大利亚阿德莱德高度城市化的港河河口印度-太平洋瓶鼻海豚（Tursiops aduncus）和长鼻真海豹（Arctocephalus forsteri）出现的影响。我们应用广义线性模型对两个长期观测数据集（海豚：1992-2020 年，海豹：2010-2020 年）进行分析，以分析在疏浚作业、季节、降雨和海表温度的作用下观测率的变化。结果表明，海豚和海豹出现的波动与疏浚作业无关，而海表温度和季节是两种物种观测率的更强预测因子（海豹在较冷的月份更为普遍，海豚在夏季更为普遍）。考虑到港河河口高度工业化的环境，该地区的动物可能已经习惯了高噪音水平，因此不会受到疏浚作业的干扰。未来的研究将受益于分析疏浚作业对行为、运动模式和栖息地利用的短期影响，以确定疏浚可能导致的栖息地变化的影响。
