There is a great need to understand how resource interactions alter the functioning of ecosystems, where the selective elimination of pelagic fishes can lead to changes in food web structure. This work analyzes the trophic niches of three species of commercial importance in the Galapagos Marine Reserve, yellowfin tuna, Thunnus albacares (TA), skipjack tuna, Katsuwonus pelamis (KP), and wahoo, Acanthocybium solandri (AS), via multiple analyses. According to the prey-specific index of relative importance, the most important prey for TA was Dosidicus gigas , while for AS it was unidentified pelagic fish. Interspecific differences were found between the isotopic signatures of AS and those of TA and KP. The isotope mixing model provides evidence for some predominance of D. gigas in the diets of TA and KP, while the fishes Selar crumenophthalmus and Paranthias colonus contribute to the diet of AS. The stable isotope Bayesian ellipses show a high overlap between TA and KP, suggesting a similar use of resources and feeding areas, while the ellipse of AS does not overlap with that of the other species. Both AS and TA were present around the islands more commonly during the day, with a peak in detections in the morning for AS and a greater presence of TA throughout the afternoon; there were only a few detections of KP in the days immediately after tagging. In summary, the results of this study suggest a pelagic foraging strategy with differential consumption of prey between AS and the other species.

中文翻译：

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栖息在加拉帕戈斯海洋保护区的三种远洋鱼类的营养偏好：使用多重分析进行生态推断

非常需要了解资源相互作用如何改变生态系统的功能，其中选择性消灭远洋鱼类会导致食物网结构的变化。这项工作通过多项分析分析了加拉帕戈斯海洋保护区中三种具有商业重要性的物种的营养生态位，即黄鳍金枪鱼、金枪鱼 (TA)、鲣鱼、Katsuwonus pelamis (KP) 和 wahoo、Acanthocybium solandri (AS)。根据相对重要性的特定猎物指数，TA最重要的猎物是Dosidicus gigas，而AS最重要的猎物是未鉴定的中上层鱼类。在 AS 的同位素特征与 TA 和 KP 的同位素特征之间发现了种间差异。同位素混合模型为 TA 和 KP 日粮中 D. gigas 的某些优势提供了证据，而鱼 Selar crumenophthalmus 和 Paranthias colus 对 AS 的饮食有贡献。稳定同位素贝叶斯椭圆显示 TA 和 KP 之间的高度重叠，表明资源利用和摄食区域相似，而 AS 的椭圆与其他物种的椭圆不重叠。AS 和 TA 在白天更常出现在岛屿周围，AS 的检测在早上达到高峰，而整个下午 TA 的存在量更大；在标记后的几天内只有少数检测到 KP。总之，这项研究的结果提出了一种远洋觅食策略，AS 和其他物种之间的猎物消耗量有所不同。建议类似的资源使用和饲养区域，而 AS 的椭圆与其他物种的椭圆不重叠。AS 和 TA 在白天更常出现在岛屿周围，AS 的检测在早上达到高峰，而整个下午 TA 的存在量更大；在标记后的几天内只有少数检测到 KP。总之，这项研究的结果提出了一种远洋觅食策略，AS 和其他物种之间的猎物消耗量有所不同。建议类似的资源使用和饲养区域，而 AS 的椭圆与其他物种的椭圆不重叠。AS 和 TA 在白天更常出现在岛屿周围，AS 的检测在早上达到高峰，而整个下午 TA 的存在量更大；在标记后的几天内只有少数检测到 KP。总之，这项研究的结果提出了一种远洋觅食策略，AS 和其他物种之间的猎物消耗量有所不同。在标记后的几天内只有少数检测到 KP。总之，这项研究的结果提出了一种远洋觅食策略，AS 和其他物种之间的猎物消耗量有所不同。在标记后的几天内只有少数检测到 KP。总之，这项研究的结果表明了一种远洋觅食策略，AS 和其他物种之间的猎物消耗量有所不同。