MARE - Marine and Environmental Sciences Centre, ISPA, Instituto Universitário, Lisbon, Portugal; Departamento de Biologia Animal, Faculdade de Ciências, Universidade de Lisboa, Lisbon, Portugal.
MARE - Marine and Environmental Sciences Centre, ISPA, Instituto Universitário, Lisbon, Portugal; Departamento de Biologia Animal and cE3c_Centre for Ecology, Evolution and Environmental Changes, Faculdade de Ciências, Universidade de Lisboa, Lisbon, Portugal.
Sci Total Environ. 2022 Jul 15;830:154735. doi: 10.1016/j.scitotenv.2022.154735. Epub 2022 Mar 23.
Anthropogenic noise is a growing threat to marine organisms, including fish. Yet very few studies have addressed the impact of anthropogenic noise on fish reproduction, especially in situ. In this study, we investigated the impacts of boat noise exposure in the reproductive success of wild Lusitanian toadfish (Halobatrachus didactylus), a species that relies on advertisement calls for mate attraction, using behavioural, physiological and reproductive endpoints. Two sets of artificial nests were deployed in the Tagus estuary and exposed to either ambient sound or boat noise during their breeding season. Toadfish males spontaneously used these nests to breed. We inspected nests for occupation and the presence of eggs in six spring low tides (in two years) and assessed male vocal activity and stress responses. Boat noise did not affect nest occupation by males but impacted reproductive success by decreasing the likelihood of receiving eggs, decreasing the number of live eggs and increasing the number of dead eggs, compared to control males. Treatment males also showed depressed vocal activity and slightly higher cortisol levels. The assessment of oxidative stress and energy metabolism-related biomarkers revealed no oxidative damage in noise exposed males despite having lower antioxidant responses and pointed towards a decrease in the activity levels of energy metabolism-related biomarkers. These results suggest that males exposed to boat noise depressed their metabolism and their activity (such as parental care and mate attraction) to cope with an acoustic stressor, consistent with a freezing defensive response/behaviour. Together, our study demonstrates that boat noise has severe impacts on reproductive fitness in Lusitanian toadfish. We argue that, at least fishes that cannot easily avoid noise sources due to their dependence on specific spawning sites, may incur in significant direct fitness costs due to chronic noise exposure.
人为噪声是海洋生物（包括鱼类）面临的一个日益严重的威胁。然而，很少有研究探讨人为噪声对鱼类繁殖的影响，尤其是在现场。在这项研究中，我们调查了船只噪声暴露对野生葡萄牙多鳍鱼（Halobatrachus didactylus）繁殖成功的影响，该物种依赖于广告叫声来吸引配偶，使用行为、生理和繁殖终点。两组人工巢穴在塔古斯河口部署，并在繁殖季节期间暴露于环境声音或船只噪声中。雄性多鳍鱼自发地使用这些巢穴繁殖。我们在六个春季低潮期（两年内）检查巢穴的占用情况和卵的存在情况，并评估雄性的发声活动和应激反应。船只噪声并没有影响雄性对巢穴的占用，但与对照雄性相比，它降低了接收卵子的可能性，减少了活卵的数量，增加了死卵的数量，从而影响了繁殖成功。与对照雄性相比，处理组雄性的发声活动也明显减少，皮质醇水平略高。氧化应激和能量代谢相关生物标志物的评估表明，尽管噪声暴露组雄性的抗氧化反应较低，但没有出现氧化损伤，并表明与能量代谢相关的生物标志物的活性水平降低。这些结果表明，暴露于船只噪声的雄性会抑制其代谢和活动（如亲代照顾和配偶吸引）以应对声应激，这与冻结防御反应/行为一致。总之，我们的研究表明，船只噪声对葡萄牙多鳍鱼的繁殖适应性有严重影响。我们认为，至少那些由于依赖特定产卵地点而无法轻易避免噪声源的鱼类，可能会因长期的噪声暴露而遭受重大的直接适应度成本。
