1. Marine aquaculture, and its fast-growing development, has the potential for wider environmental, ecosystem, and biodiversity impacts. This study assesses the impact of fish farming on a bottlenose dolphin (Tursiops truncatus) population within the Gulf of Ambracia (western Greece) between 2007 and 2018. Two different study areas were defined in order to investigate differences on occurrence, abundance, behaviour, and seasonal fluctuations between them: a ‘control area’, in the north-western side of the Gulf; and a ‘fish farm area’, in the south west, where the highest density of fish farm cages is found.
2. A total of 169 daily surveys were dedicated to the control area and 74 days were dedicated to the fish farm area, yielding 104 and 37 sightings, respectively. Both the probability of detecting dolphins (U = 6,763.000, P = 0.002) and the group sizes (U = 578.000, P < 0.001) were smaller around fish farms.
3. Seasonality analyses were restricted to 2007–2008, as this was the period with year-round effort. Results revealed that dolphins were more frequently seen around fish farms in the winter (Kruskal–Wallis test, P = 0.036).
4. From the 40 identified individuals that were re-sighted at least 10 times during the study period, 21 used the fish farm area less than expected according to sampling effort, and 10 of them were never observed in that area (binomial test, P < 0.05).
5. The results revealed an impact of fish farms on the distribution of bottlenose dolphins in the Gulf of Ambracia. This information should be taken into consideration when defining ecosystem-based management measures within the management plan, which is currently in preparation for this Natura 2000 site.

中文翻译：

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常见的宽吻海豚（Tursiops truncatus）与希腊西部安布拉西亚湾养鱼场的互动

1. 海水养殖及其快速发展，有可能对环境、生态系统和生物多样性产生更广泛的影响。本研究评估了2007 年至 2018 年间养鱼对Ambracia 湾（希腊西部）宽吻海豚（Tursiops truncatus）种群的影响。定义了两个不同的研究区域，以调查在发生、丰度、行为和它们之间的季节性波动：海湾西北部的“控制区”；西南部的“养鱼场区”是养鱼场网箱密度最高的地方。
2. 每天共对控制区进行了 169 次调查，对养鱼场区域进行了 74 天的调查，分别产生了 104 次和 37 次目击。 在养鱼场附近发现海豚的概率 ( U  = 6,763.000, P  = 0.002) 和群体规模 ( U  = 578.000, P < 0.001) 都较小。
3. 季节性分析仅限于 2007-2008 年，因为这是全年努力的时期。结果显示，冬季在养鱼场周围更频繁地看到海豚（Kruskal-Wallis 检验，P  = 0.036）。
4. 在研究期间至少复视 10 次的 40 名已识别个体中，21 人使用的养鱼场面积少于根据抽样工作的预期，其中 10 人从未在该地区观察到（二项式检验，P  < 0.05 ）。
5. 结果揭示了养鱼场对安布拉西亚湾宽吻海豚分布的影响。在管理计划中定义基于生态系统的管理措施时应考虑这些信息，该计划目前正在为这个 Natura 2000 站点做准备。