Resolving the preferred prey items and dietary proportions of leopard seals is central to understanding food-web dynamics in the rapidly-warming Antarctic Peninsula region. Previous studies have identified a wide range of prey items; however, due to anecdotal or otherwise limited information, leopard seal diets remain unresolved by seal sex, individual, body size, region, and season. Over the 2013, 2014, and 2017 field seasons we collected scat, tissue samples (red blood cells and plasma; n = 23) for stable isotope analyses, and previously-reported animal-borne video from 19 adult leopard seals foraging near mesopredator breeding colonies at Cape Shirreff, Livingston Island. We summarized a priori diet information from scat and video analysis and applied a three-isotope (δ13C, δ15N, δ34S), four-source (fish, fur seal, krill, penguin) Bayesian mixing model to examine temporal variability in both prey sources and leopard seal tissues. The austral spring diets of males and females focused on Antarctic krill (31.7–38.0%), notothen fish (31.6–36.5%), and penguin (24.4–26.9%) and were consistent across all 3 years. Several lines of evidence suggest the transition to summer foraging was distinct for males and females. Female diets transitioned rapidly to higher δ15N values (+2.1‰), indicating increased consumption of penguin (29.5–46.2%) and energy-dense Antarctic fur seal pup (21.3–37.6%). The seasonal increase in leopard seal δ15N values, and thus fur seal in their diet, was predictably related to larger body size; it may also be forcing reductions to the largest Antarctic fur seal colony in the Antarctic Peninsula. Our ensemble sampling approach reduces historical biases in monitoring marine apex predator diets. Further, our results are necessary to best inform regional fisheries management planning.

中文翻译：

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在迅速变暖的极地地区，豹海豹的饮食因年份、季节、性别和体型而异。

解决豹海豹的首选猎物和饮食比例对于了解快速变暖的南极半岛地区的食物网动态至关重要。以前的研究已经确定了广泛的猎物；然而，由于轶事或其他有限的信息，豹海豹的饮食仍然无法通过海豹的性别、个体、体型、地区和季节来解决。在 2013 年、2014 年和 2017 年的野外季节，我们收集了粪便、组​​织样本（红细胞和血浆；n = 23）用于稳定同位素分析，以及之前报道的 19 只成年豹海豹在中食性动物繁殖地附近觅食的动物传播视频在利文斯顿岛的希里夫角。我们从粪便和视频分析中总结了先验饮食信息，并应用了三同位素（δ13C、δ15N、δ34S）、四源（鱼、海狗、磷虾、penguin) 贝叶斯混合模型，用于检查猎物来源和豹海豹组织的时间变异性。男性和女性的南方春季饮食主要以南极磷虾（31.7-38.0%）、鱼类（31.6-36.5%）和企鹅（24.4-26.9%）为主，并且在所有 3 年中保持一致。几条证据表明，雄性和雌性向夏季觅食的过渡是不同的。雌性饮食迅速转变为更高的 δ15N 值（+2.1‰），表明企鹅（29.5-46.2%）和能量密集的南极海狗幼崽（21.3-37.6%）的消耗量增加。可以预见，豹海豹 δ15N 值的季节性增加以及它们饮食中的毛皮海豹与较大的体型有关；它还可能迫使南极半岛最大的南极海狗栖息地减少。我们的整体抽样方法减少了监测海洋顶级捕食者饮食的历史偏差。此外，我们的结果对于最好地为区域渔业管理规划提供信息是必要的。