Páez-Rosas Diego, Insuasti-Zarate Paul, Riofrío-Lazo Marjorie, Galván-Magaña Felipe
Galapagos Science Center, Universidad San Francisco de Quito, Galápagos, Ecuador.
Unidad Técnica San Cristóbal, Dirección del Parque Nacional Galápagos, Galápagos, Ecuador.
PeerJ. 2018 May 25;6:e4818. doi: 10.7717/peerj.4818. eCollection 2018.
There is great concern about the future of sharks in Ecuador because of the lack of biological knowledge of most species that inhabit the region. This paper analyzes the feeding behavior of the pelagic thresher shark (), the blue shark () and the silky shark () through the use of stable isotopes of carbon and nitrogen (C and N), with the aim of determining the degree of interaction between these species in the Galapagos Marine Reserve. No interspecific differences were found in use of oceanic vs. inshore feeding areas (C: Kruskal-Wallis test, = 0.09). The position in the hierarchy of the food web where feeds differed from that of the other species (N: Kruskal-Wallis test, = 0.01). There were no significant differences in C and N values between males and females of the three species (Student's -test, > 0.05), which suggests that both sexes have a similar feeding behavior. A specialist strategy was observed in (trophic niche breadth TNB = 0.69), while the other species were found to be generalist ( TNB = 1.50 and TNB = 1.09). The estimated trophic level (TL) varied between the three species. occupied the highest trophic level (TL = 4.4), making it a quaternary predator in the region. The results of this study coincide with the identified behavior in these predators in other areas of the tropical Pacific (Colombia and Mexico), and suggest a pelagic foraging strategy with differential consumption of prey between the three species. These ecological aspects can provide timely information when implementing in conservation measures for these shark species in the Tropical Pacific and Galapagos Marine Reserve.
由于对厄瓜多尔大多数鲨鱼物种缺乏生物学知识，人们对该国鲨鱼的未来深感担忧。本文通过使用碳和氮的稳定同位素（C和N）分析了太平洋长尾鲨（）、大青鲨（）和丝鲨（）的摄食行为，目的是确定这些物种在加拉帕戈斯海洋保护区内的相互作用程度。在远洋与近岸觅食区域的利用方面未发现种间差异（C：Kruskal-Wallis检验，=0.09）。太平洋长尾鲨在食物网中的等级地位与其他物种不同（N：Kruskal-Wallis检验，=0.01）。三种鲨鱼的雄性和雌性之间的C和N值没有显著差异（学生t检验，>0.05），这表明两性具有相似的摄食行为。观察到太平洋长尾鲨采取特化策略（营养生态位宽度TNB = 0.69），而其他物种则为泛化种（大青鲨TNB = 1.50，丝鲨TNB = 1.09）。三种鲨鱼的估计营养级（TL）各不相同。太平洋长尾鲨占据最高营养级（TL = 4.4），使其成为该区域的四级捕食者。本研究结果与热带太平洋其他地区（哥伦比亚和墨西哥）这些捕食者的已确定行为一致，并表明三种鲨鱼在远洋觅食策略上对猎物的消耗存在差异。在为热带太平洋和加拉帕戈斯海洋保护区的这些鲨鱼物种实施保护措施时，这些生态方面可以提供及时的信息。
