Biological production in the oceanic zone (i.e. waters beyond the continental shelves) is typically spatially patchy and strongly seasonal. In response, seabirds have adapted to move rapidly within and between ocean basins, making them important pelagic consumers. Studies in the Pacific, Southern and Indian Oceans have shown that seabirds are relatively abundant in major frontal systems, with species composition varying by water mass. In contrast, surprisingly little was known about seabird distribution in the oceanic North Atlantic until recent tracking showed that relative abundance and diversity peak in the Sub-polar Frontal Zone, west of the Mid-Atlantic Ridge, now proposed as a Marine Protected Area. However, absolute seabird abundance, distribution, age and species composition, and their potential environmental drivers in the oceanic temperate NW Atlantic remain largely unknown. Consequently, we systematically surveyed seabirds and environmental conditions across this area by ship in June 2017, then modelled the density of common species as functions of environmental covariates, validating model predictions against independent tracking data. Medium-sized petrels (99.8%), especially Great Shearwaters (Ardenna gravis, 63%), accounted for the majority of total avian biomass, which correlated at the macroscale with net primary production and peaked at the sub-polar front. At the mesoscale, the density of each species was associated with sea surface temperature, indicating zonation by water mass. Most species also exhibited scale-dependent associations with eddies and fronts. Approximately 51, 26, 23, 7 and 1 % of the currently estimated Atlantic populations of Cory's Shearwaters (Calonectris borealis), Great Shearwaters, Sooty Shearwaters (A. grisea), Northern Fulmars (Fulmarus glacialis) and Leach’s Storm-petrels (Oceanodroma leucorhoa) occurred in the area during our survey, many of which were undergoing moult (a vital maintena nce activity). For some species, these estimates are higher than suggested by tracking, probably due to the presence of immatures and birds from untracked populations. Our results support the conclusion that MPA status is warranted and provide a baseline against which future changes can be assessed. Moreover, they indicate potential drivers of seabird abundance and diversity in the oceanic zone of the North Atlantic that should be investigated further.

大洋区（即大陆架以外的水域）的生物生产通常在空间上不完整且季节性很强。作为回应，海鸟适应了在海盆内和海盆之间快速移动，使它们成为重要的远洋消费者。太平洋、南洋和印度洋的研究表明，海鸟在主要的锋面系统中相对丰富，物种组成因水量而异。相比之下，令人惊讶的是，人们对北大西洋海洋中的海鸟分布知之甚少，直到最近的跟踪表明，中大西洋海脊以西的副极地锋区的相对丰度和多样性达到峰值，现在被提议为海洋保护区。然而，绝对海鸟数量、分布、年龄和物种组成，它们在海洋温带西北大西洋中的潜在环境驱动因素在很大程度上仍然未知。因此，我们于 2017 年 6 月通过船舶系统地调查了该地区的海鸟和环境条件，然后将常见物种的密度建模为环境协变量的函数，根据独立跟踪数据验证模型预测。中型海燕 (99.8%)，尤其是大海鸥 (Ardenna gravis，63%)，占鸟类总生物量的大部分，在宏观尺度上与净初级生产相关，并在次极地前沿达到峰值。在中尺度上，每个物种的密度与海面温度有关，表明水质量的分区。大多数物种还表现出与涡流和锋面相关的尺度相关性。大约 51%、26%、23%、7% 和 1% 目前估计的大西洋海鸥( Calonectris borealis )、Great Shearwaters、Sooty Shearwaters ( A. grisea )、Northern Fulmers ( Fulmarus glacialis ) 和 Leach's Storm-海燕) 在我们调查期间发生在该地区，其中许多正在换羽（一项重要的维护活动）。对于某些物种，这些估计值高于跟踪建议的估计值，这可能是由于未跟踪种群的未成熟鸟类和鸟类的存在。我们的结果支持 MPA 状态是有保证的结论，并提供了一个基线，可以用来评估未来的变化。此外，它们指出了北大西洋海洋区海鸟丰度和多样性的潜在驱动因素，应进一步调查。