What do the empty stomachs of northern pike (Esox lucius) reveal? Insights from carbon (δ13C) and nitrogen (δ15N) stable isotopes
What do the empty stomachs of northern pike (Esox lucius) reveal? Insights from carbon (δ13C) and nitrogen (δ15N) stable isotopes
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北梭子鱼 (Esox lucius) 的空胃揭示了碳 (δ13C) 和氮 (δ15N) 稳定同位素的启示？
DOI：
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发表时间：
2008
影响因子：
1.4
通讯作者：
P. Magnan
中科院分区：
文献类型：
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作者：
Y. Paradis;A. Bertolo;P. Magnan
个体空胃（FES）的频率在北方梭子鱼种群中变化很大。然而，FES很少在这个物种中进行分析，其意义仍然没有完全理解。有人认为，高的FES可能反映了强烈的食鱼行为，而低的FES可能反映了更高的利用无脊椎动物。我们比较了胃内容物和营养位置的北方狗鱼在16个种群的个人主要以鱼类或底栖无脊椎动物为食。我们测试的假设，北方狗鱼空胃或鱼在他们的胃有一个更高的营养地位比个人无脊椎动物喂养。碳（δ 13 C）和氮（δ 15 N）稳定同位素特征被用来估计个体的营养位置。我们发现，在食鱼动物，无脊椎动物的饲养者，和北方狗鱼空胃之间的营养位置没有显着差异。北方梭子鱼的平均营养位置较高（平均值±标准差= 4.3 ± 0.4，n = 66），且与体长相关。这些结果表明，虽然无脊椎动物可能是加拿大地盾湖北方梭子鱼饮食的重要组成部分，鱼类仍然是主要的猎物。因此，在我们的研究湖泊无脊椎动物喂养将反映一个机会主义，而不是专门的喂养策略。
The frequency of individuals with empty stomachs (FES) can vary greatly among northern pike populations. However, the FES has only seldom been analyzed in this species and its meaning is still not fully understood. It has been suggested that a high FES may reflect a strongly piscivorous behaviour while low FES could reflect a higher utilization of invertebrates. We compared the stomach contents and the trophic position of northern pike in 16 populations of individuals feeding mainly on fish or benthic invertebrates. We tested the hypothesis that northern pike with empty stomachs or with fish in their stomachs have a higher trophic position than individuals feeding on invertebrates. Carbon (δ13C) and nitrogen (δ15N) stable isotope signatures were used to estimate the trophic position of individuals. We found no significant difference in the trophic position among piscivores, invertebrate feeders, and northern pike with empty stomachs. The average trophic position of northern pike was high (mean ± SD = 4.3 ± 0.4, n = 66) and was correlated with total length. These results indicate that, although invertebrates could be an important part of the diet of northern pike in Canadian Shield lakes, fish are still the dominant prey. Hence, feeding on invertebrates in our study lakes would reflect an opportunistic rather than a specialized feeding strategy.