Seabird bycatch in a Baltic coastal gillnet fishery is orders of magnitude larger than official reports

IF 1.4 4区环境科学与生态学 Q3 BIODIVERSITY CONSERVATION

Avian Conservation and Ecology Pub Date : 2022-01-01 DOI:10.5751/ace-02153-170131

J. Morkūnas, S. Oppel, Modestas Bružas, Y. Rouxel, R. Morkūnė, Danielle L. Mitchell

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引用次数: 3

Abstract

, ABSTRACT. Bycatch, or the incidental capture of non-target species in fisheries, has been identified as one of the major threats affecting seabird populations worldwide. In the Baltic Sea, a globally important area for wintering seabirds, bycatch in gillnets represents an important cause of human-induced mortality for seabird species whose populations have declined significantly in recent decades. Although countries are required by European law to report official bycatch data, a lack of data on bycatch in small-scale fisheries impedes an assessment of the contribution of bycatch to declines of seabird populations. This study presents data on the total seabird bycatch in the small-scale coastal fishery for an entire country, Lithuania, in the southeastern Baltic Sea, during the 2015–2020 winter period. An average of 19.3% of the total fishing effort in net-meter days (15.5% of fishing days) were observed each winter season, resulting in observations of 909 bycaught birds from 15 species. Two species composed two-thirds of the total bycatch, Long-tailed Duck ( Clangula hyemalis ; 42.1%) and Velvet Scoter ( Melanitta fusca ; 35.4%). Bycatch composition varied with depth, with the majority of bycatch occurring in nets set at depths ≤ 10 m. Adult males dominated the bycatch of benthivorous sea ducks, whereas adult females composed the majority of piscivorous birds caught. Low numbers of juveniles in the bycatch may indicate different wintering sites for young birds. We estimate that between 1500 and 3000 seabirds were bycaught annually in the Lithuanian small-scale coastal fishery in the 2015–2020 period. Because this number is orders of magnitude larger than the bycatch officially reported by the Lithuanian authorities (six birds), our study highlights deficiencies in the country’s current bycatch reporting. In contrast to official statistics based on inadequate data, the unintended capture of seabirds in gillnets remains high, despite financial investments to minimize the impact of fisheries on biodiversity.

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波罗的海沿岸刺网渔业的海鸟副渔获量比官方报告的要大几个数量级

、抽象。副渔获，或在渔业中偶然捕获的非目标物种，已被确定为影响全球海鸟种群的主要威胁之一。波罗的海是全球重要的越冬海鸟栖息地，刺网的副渔获是近几十年来海鸟数量显著减少的人为致死的重要原因。虽然欧洲法律要求各国报告官方附带渔获物数据，但由于缺乏小规模渔业附带渔获物的数据，妨碍了对附带渔获物对海鸟种群减少的贡献进行评估。本研究提供了2015-2020年冬季期间波罗的海东南部立陶宛整个国家小规模沿海渔业的海鸟副渔获总量数据。每年冬季平均捕获净米日总渔获量的19.3%(占渔获日的15.5%)，共捕获15种909只副渔获。长尾鸭(Clangula hyemalis;42.1%)和天鹅绒斯科特(Melanitta fusca;35.4%)。副渔获物的组成随深度而变化，大部分副渔获物发生在深度≤10米的渔网中。腹食性海鸭的副渔获物以成年雄鸭为主，而鱼食性海鸭的副渔获物以成年雌鸭为主。副渔获物中幼鸟数量少可能表明幼鸟的越冬地点不同。我们估计，在2015-2020年期间，立陶宛小规模沿海渔业每年捕获1500至3000只海鸟。由于这一数字比立陶宛当局官方报告的副渔获量(6只)大了几个数量级，我们的研究突出了该国目前副渔获报告的不足之处。与基于不充分数据的官方统计数据相反，尽管为尽量减少渔业对生物多样性的影响而进行了财政投资，但刺网意外捕获海鸟的情况仍然很高。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Avian Conservation and Ecology BIODIVERSITY CONSERVATION-ORNITHOLOGY

CiteScore

2.20

自引率

7.10%

发文量

审稿时长

>12 weeks

期刊介绍： Avian Conservation and Ecology is an open-access, fully electronic scientific journal, sponsored by the Society of Canadian Ornithologists and Birds Canada. We publish papers that are scientifically rigorous and relevant to the bird conservation community in a cost-effective electronic approach that makes them freely available to scientists and the public in real-time. ACE is a fully indexed ISSN journal that welcomes contributions from scientists all over the world. While the name of the journal implies a publication niche of conservation AND ecology, we think the theme of conservation THROUGH ecology provides a better sense of our purpose. As such, we are particularly interested in contributions that use a scientifically sound and rigorous approach to the achievement of avian conservation as revealed through insights into ecological principles and processes. Papers are expected to fall along a continuum of pure conservation and management at one end to more pure ecology at the other but our emphasis will be on those contributions with direct relevance to conservation objectives.