CESAM, Centre for Environmental and Marine Studies, Departamento de Biologia Animal, Faculdade de Ciências da Universidade de Lisboa, Campo Grande, 1749-016, Lisbon, Portugal.
MARE, Marine and Environmental Sciences Centre, ISPA-Instituto Universitário, Rua Jardim do Tabaco 34, 1149-041, Lisbon, Portugal.
Mar Environ Res. 2021 Mar;165:105232. doi: 10.1016/j.marenvres.2020.105232. Epub 2020 Dec 17.
The dynamics of the subtropical pelagic ecosystems of the Northeast Atlantic are still poorly known due to the high costs associated with sampling large oceanic areas. Top predators can be used as alternative low-cost samplers and indicators of the temporal variability of such systems. To study the variation in the composition of pelagic species through time in the broad Canary current region, we analysed foraging trips and regurgitations of Cory's shearwaters Calonectris borealis nesting on Selvagens islands, in 2008-2011 and 2016-2018. Fisheries data, oceanographic variables and the North Atlantic Oscillation were explored as possible explanatory variables for trends in behaviour and diet. Cory's shearwaters' diet, complemented by fisheries data, revealed marked changes in the composition of the pelagic fish communities. In 2016 there was a peak in the abundance of the Atlantic chub mackerel Scomber colias, followed by an explosive increase in the abundance of the Longspine snipefish Macroramphosus scolopax in 2017 and 2018, as deduced from the diet composition of the Cory's shearwater, and supported by fisheries data, in the broad oceanic area surrounding the Selvagens islands. Oceanographic variables did not show fluctuations correlated with these marked shifts in pelagic fish availability, the causes of which remain largely unknown. This study highlights the importance of the Atlantic chub mackerel and of the Longspine snipefish in the Madeira/Canary region and exemplifies the efficiency of avian predators in revealing rapid changes in pelagic communities of oceanic domains. Such trends and variations need to be better monitored and understood to measure the impact of ongoing global changes and to sustainably manage the marine environment and resources.
东北大西洋亚热带海洋浮游生态系统的动态仍知之甚少，这是由于对大型海洋区域进行采样的成本高昂所致。顶级掠食者可用作替代的低成本采样器和此类系统时间可变性的指示物。为了研究宽阔的加那利海流地区浮游物种组成随时间的变化，我们分析了 2008-2011 年和 2016-2018 年在塞尔瓦斯群岛筑巢的角海雀 Calonectris borealis 的觅食和反刍行为。渔业数据、海洋变量和北大西洋涛动被探索为行为和饮食趋势的可能解释变量。角海雀的饮食，辅以渔业数据，揭示了浮游鱼类群落组成的明显变化。2016 年，大西洋鲭鱼 Scomber colias 的丰度达到峰值，随后在 2017 年和 2018 年，长鳍 snipefish Macroramphosus scolopax 的丰度呈爆炸式增长，这可以从角海雀的饮食组成中推断出来，并得到了塞尔瓦斯群岛周围广阔海域渔业数据的支持。海洋变量没有显示出与这些浮游鱼类可利用性明显变化相关的波动，其原因在很大程度上仍不清楚。本研究强调了大西洋鲭鱼和长鳍 snipefish 在马德拉/加那利群岛地区的重要性，并举例说明了鸟类捕食者在揭示海洋领域浮游群落快速变化方面的效率。需要更好地监测和理解这些趋势和变化，以衡量正在发生的全球变化的影响，并可持续管理海洋环境和资源。
