IMAR, Instituto do Mar, Departamento de Oceanografia e Pescas, Universidade dos Açores, 9901-862, Horta, Portugal; OKEANOS, Universidade dos Açores, Departamento de Oceanografia e Pescas, 9901-862, Horta, Portugal.
IMAR, Instituto do Mar, Departamento de Oceanografia e Pescas, Universidade dos Açores, 9901-862, Horta, Portugal; OKEANOS, Universidade dos Açores, Departamento de Oceanografia e Pescas, 9901-862, Horta, Portugal; MARE, Marine and Environmental Sciences Centre, Universidade dos Açores, 9901-862, Horta, Portugal.
Mar Environ Res. 2018 Oct;141:225-232. doi: 10.1016/j.marenvres.2018.09.015. Epub 2018 Sep 11.
The distribution and composition of macro litter floating around oceanic islands is poorly known, especially in the North Atlantic. Due to its isolated location at the fringe of the North Atlantic subtropical gyre, the Azores archipelago has recently been proposed as a potential retention zone for floating litter. To further investigate this assumption, opportunistic surveys from pole-and-line tuna fishing boats were performed from 2015 to 2017 to document (1) the distribution and (2) the composition of the floating macro litter present off the Azores and Madeira islands. Among the 2406 visual transects, 482 floating debris were recorded and were mainly composed of general plastic user items (48%), plastic packaging (21%) and derelict fishing gears (18%). Average number of debris per transect was 0.19 ± 0.5, with a total number ranging between 0 and 5 items per transect. For the majority of transects (84%), no debris was observed, 13% of the transects contained a single item, and only 3% contained more than one item. Although debris between 2.5 and 5 cm were recorded, 93% of the debris were larger than 5 cm. The GLMs showed strong effect of the observer (p < 0.001) and the standardized densities accounting for the observer bias were higher (1.39 ± 0.14 items.km) than the observed densities (0.78 ± 0.07 items.km). Debris densities were however relatively low and tended to aggregate around the Central group of the Azores (standardized mean: 0.90 ± 0.20 items.km). Our findings therefore suggest that most of the debris might originate from far away land-based sources and from fishing activities. This study highlights the potential of fisheries observer programs to obtain cost-effective information on floating macro debris that are essential to support the implementation of the European Marine Strategy Framework Directive.
海洋岛屿周围的大型漂浮垃圾的分布和组成情况知之甚少，尤其是在北大西洋地区。由于地处北大西洋亚热带环流边缘的孤立位置，亚速尔群岛最近被提议为可能的漂浮垃圾滞留区。为了进一步验证这一假设，从 2015 年到 2017 年，利用金枪鱼延绳钓渔船进行了机会性调查，以记录（1）亚速尔群岛和马德拉群岛周围的漂浮大型垃圾的分布情况，以及（2）其组成情况。在 2406 个目视横切中记录了 482 个漂浮碎片，主要由通用塑料用户用品（48%）、塑料包装（21%）和废弃渔具（18%）组成。每个横切的平均碎片数量为 0.19±0.5，每个横切的碎片总数在 0 到 5 个之间。在大多数横切中（84%），没有发现碎片，13%的横切中有一个碎片，只有 3%的横切中有多个碎片。虽然记录了 2.5 到 5 厘米之间的碎片，但 93%的碎片大于 5 厘米。GLM 显示了观察者的强烈影响（p<0.001），并且考虑到观察者偏差的标准化密度更高（1.39±0.14 个/km），而观察到的密度（0.78±0.07 个/km）。然而，碎片密度相对较低，并且倾向于在亚速尔群岛中部聚集（标准化平均值：0.90±0.20 个/km）。因此，我们的研究结果表明，大部分碎片可能来自遥远的陆基来源和渔业活动。这项研究强调了渔业观察员计划在获取有关漂浮大型碎片的经济有效的信息方面的潜力，这些信息对于支持欧洲海洋战略框架指令的实施至关重要。
