Stable isotope analysis indicates resource partitioning and trophic niche overlap in larvae of four tuna species in the Gulf of Mexico
Stable isotope analysis indicates resource partitioning and trophic niche overlap in larvae of four tuna species in the Gulf of Mexico
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DOI：
10.3354/meps12958
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发表时间：
2019-06-04
影响因子：
2.5
通讯作者：
Garcia, Alberto
中科院分区：
文献类型：
--
作者：
Laiz-Carrion, Raul;Gerard, Trika;Garcia, Alberto
在这项研究中，我们使用整体组织稳定同位素分析(SIA(Bulk))和化合物特异性氨基酸分析(CSIA(AA))，对墨西哥湾蓝鳍金枪鱼Thunnus thynnus幼体以及共生的黑鳍金枪鱼Tatlanticus、子弹金枪鱼Auxis rochei和Skipjack Katsuwan Pelamis幼体的营养生态进行了评估。总体氮(增量N-15(散装))和碳(增量C-13(散装))的值在不同物种之间差异很大，这表明由于适应过程允许这些金枪鱼在生命早期共享生态系统的营养资源，资源得到了分配。Pelamis具有最大的同位素生态位宽度，这可能是由于与其他物种相比捕食年龄较早所致，与Thynnus、Tatlanticus和A.rochei的同位素生态位重叠分别为13.5%、15.8%和31.2%。这种营养重叠表明这4种金枪鱼幼体之间存在竞争和营养分化的混合。用SIA Bink和CSIA(AA)测量的Thynnus前屈幼虫和后屈曲幼虫中较高的氮同位素特征表明母体同位素传递，以及类似首都繁殖者的特征。相反，其他3个物种的氮同位素比率在个体发育阶段之间是相似的。这些观察结果表明，在研究区域内，大西洋金龟子、白纹伊蚊和罗氏金龟子的繁殖策略与桑天牛不同。CSIA(AA)估算的4个物种的营养位置(TP)之间没有显著差异，而SIA(Bulk)估算的梭子蟹的TP较高。TP估计的这些差异可能归因于基线估计的差异。
In this study we assessed the trophic ecology of bluefin tuna Thunnus thynnus larvae from the Gulf of Mexico, together with the co-occurring larvae of blackfin tuna T. atlanticus, bullet tuna Auxis rochei, and skipjack Katsuwonus pelamis, using both bulk-tissue stable isotope analysis (SIA(bulk)) and compound-specific analysis of amino acids (CSIA(AA)). Bulk nitrogen (delta N-15(bulk)) and carbon (delta C-13(bulk)) values differed significantly among species, suggesting partitioning of resources due to an adaptive process allowing these tunas to share the ecosystem's trophic resources during this early life period. K. pelamis had the largest isotopic niche width, likely due to piscivorous feeding at an earlier age compared to the other species, with an isotopic niche overlap of 13.5% with T. thynnus, 15.8% with T. atlanticus, and 31.2% with A. rochei. This trophic overlap suggests a mix of competition and trophic differentiation among these 4 species of tuna larvae. Higher nitrogen isotopic signatures in preflexion versus postflexion larvae of T. thynnus measured using both SIA bink and CSIA(AA) indicate maternal isotopic transmission, as well as 'capital breeder'-like characteristics. In contrast, the nitrogen isotopic ratios of the other 3 species were similar between ontogenetic stages. These observations suggest different breeding strategies within the study area for T. atlanticus, K. pelamis, and A. rochei compared to T. thynnus. No significant differences were observed among the 4 species' trophic positions (TPs) estimated by CSIA(AA), whereas a higher TP was observed for T. thynnus by SIA(bulk). These differences in TP estimation may be attributed to discrepancies in baseline estimates.