Yellowfin tuna are the mainstay of the traditional tuna fisheries in St Helena waters, but there is limited knowledge of their ecology and feeding behaviour in the area. In this study yellowfin tuna stomach contents were used to assess spatio‐temporal changes in feeding strategy and consider the role of tuna in the local ecosystem. Comparisons of the feeding spectra of yellowfin tuna between inshore regions of St Helena and oceanic seamounts demonstrated that in both areas the species was largely piscivorous. In inshore waters yellowfin consumed more neritic fauna, including significant numbers of crab megalopa, whereas around seamounts the diet included a greater diversity of epi‐ and mesopelagic fish and squids. The most important fish prey species in inshore waters was the St Helena butterflyfish Chaetodon sanctahelenae, and around seamounts was the pufferfish Lagocephalus lagocephalus. Results indicate that the diet spectrum of yellowfin tuna in St Helena waters is relatively similar to those of conspecifics living in waters with relatively low productivity, with strategies indicative of food‐poor ecosystems. The availability of coastal fauna may make areas around islands and seamounts more attractive for feeding aggregations of yellowfin tuna, compared to the open ocean. The relatively unselective feeding of yellowfin tuna means that stomachs can provide valuable data on the species diversity, particularly in remote areas with limited opportunities for dedicated research expeditions.

中文翻译：

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比较圣海伦娜和南大西洋邻近海山周围的黄鳍金枪鱼的摄食策略

黄鳍金枪鱼是圣赫勒拿水域传统金枪鱼渔业的支柱，但对该地区的生态学和摄食行为知之甚少。在这项研究中，黄鳍金枪鱼的胃内容物用于评估进食策略的时空变化并考虑金枪鱼在当地生态系统中的作用。比较圣赫勒拿岛和海洋海山沿岸的黄鳍金枪鱼的摄食光谱，结果表明在这两个地区，该物种均为食鱼性的。在近岸水域，黄鳍金枪鱼食用了更多的有害动物群，其中包括大量的蟹黄盖拉，而在海山附近，饮食则包括了上，中生鱼类和鱿鱼。近海最重要的鱼类猎物是圣赫勒拿岛蝴蝶鱼Chaetodon sanctahelenae在海山周围是河豚Lagocephalus lagocephalus。结果表明，圣赫勒拿水域中黄鳍金枪鱼的饮食谱与生活在生产力相对较低的水域中的同种异食金枪鱼的饮食谱相对相似，其策略表明食物贫乏的生态系统。与开放海洋相比，沿海动物的可利用性可能使岛屿和海山周围的地区更吸引黄鳍金枪鱼的聚集体。黄鳍金枪鱼相对非选择性的喂养意味着胃可以提供有关物种多样性的有价值的数据，特别是在偏远地区，专门研究探险的机会有限。