New trophic insights associated with the return of a top predator, bluefin tuna, to Skagerrak and the Sound

IF 2.3 2区农林科学 Q2 FISHERIES

Fisheries Research Pub Date : 2025-09-12 DOI:10.1016/j.fishres.2025.107501

Gustav Hellström , Kim Birnie-Gauvin , Petter Lundberg , William Jaktén Langert , Kristi Källo , Lene K. Sortland , Brian R. MacKenzie , Jose Luis Varela , Anders Koed , Einar Eg Nielsen , Andreas Sundelöf , Hege Sande , Maria Overgård , Henrik Baktoft , Kim Aarestrup , Tomas Brodin

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引用次数: 0

Abstract

This study examines the dietary composition of the recently reoccurring Atlantic bluefin tuna (ABFT, Thunnus thynnus) in the Skagerrak-Kattegat-Sound area of the North-East Atlantic. We analysed the stomach contents of 44 ABFT, with lengths between 232 and 295 cm (CFL), captured in August and September annually from 2020 to 2022 via rod-and-reel fishing. Our analysis identified 19 species of teleost fish, four types of squid, and one crab species, although the diet was dominated by pelagic schooling fish such as garfish (percentage of index of relative abundance (%IRI) = 22.5), herring (%IRI = 6.8), mackerel (%IRI = 6.8), and various demersal gadoid species (combined %IRI = 42). Regional variation in dietary composition between Skagerrak and the Sound indicates that ABFT exhibit foraging flexibility, primarily targeting locally abundant, energy-rich schooling fish, while occasionally consuming other prey. The prevalence of garfish in the diet, which is neither commercially targeted nor managed or regulated, highlights the importance of maintaining healthy stocks of this species for supporting the continuous return of ABFT to the area.

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与顶级捕食者蓝鳍金枪鱼回归斯卡格拉克和海湾有关的新的营养见解

本研究调查了最近在东北大西洋的斯卡格拉克-卡特加特海峡地区重新出现的大西洋蓝鳍金枪鱼（ABFT, Thunnus thynnus）的饮食组成。我们分析了44条ABFT的胃内容物，长度在232至295 cm （CFL）之间，从2020年到2022年，每年8月和9月通过鱼竿和卷轴捕鱼捕获。我们的分析发现了19种硬骨鱼，4种鱿鱼和1种螃蟹，尽管饮食中主要是远洋洄游鱼类，如garfish（相对丰度指数百分比(%IRI) = 22.5），鲱鱼（%IRI = 6.8），鲭鱼（%IRI = 6.8）和各种底栖类（总%IRI = 42）。Skagerrak和Sound之间饮食组成的区域差异表明ABFT表现出觅食的灵活性，主要针对当地丰富，能量丰富的鱼群，偶尔也会消耗其他猎物。饮食中普遍存在的garfish，既没有商业目标，也没有管理或管制，突出了维持该物种健康种群的重要性，以支持该地区ABFT的持续回归。

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来源期刊

Fisheries Research 农林科学-渔业

CiteScore

4.50

自引率

16.70%

发文量

294

审稿时长

15 weeks

期刊介绍： This journal provides an international forum for the publication of papers in the areas of fisheries science, fishing technology, fisheries management and relevant socio-economics. The scope covers fisheries in salt, brackish and freshwater systems, and all aspects of associated ecology, environmental aspects of fisheries, and economics. Both theoretical and practical papers are acceptable, including laboratory and field experimental studies relevant to fisheries. Papers on the conservation of exploitable living resources are welcome. Review and Viewpoint articles are also published. As the specified areas inevitably impinge on and interrelate with each other, the approach of the journal is multidisciplinary, and authors are encouraged to emphasise the relevance of their own work to that of other disciplines. The journal is intended for fisheries scientists, biological oceanographers, gear technologists, economists, managers, administrators, policy makers and legislators.