The distribution of prey in the ocean is spatially and temporally patchy. How predators respond to this prey patchiness may have consequences on their foraging success, and thus physical condition. The recent ability to record fine-scale movements of marine animals combined with novel home-range analyses that incorporate the dimension of time should permit a better understanding of how individuals utilise different regions of space and the consequences on their foraging success. Over a six-year study, we used T-LoCoH (Time-Local Convex Hull) home-range software to model archival GPS (Global Positioning System) data from 81 grey seals to investigate the fine-scale spatio-temporal use of space and the distribution of apparent foraging effort. Regions of home-ranges were classified according to the frequency of return visits (site fidelity) and duration of visits (intensity of use). Generalized linear mixed -effects models were used to test hypotheses on seasonal changes in foraging distribution and behaviour and the role of space-use and state on determining foraging success. Male grey seals had larger home-ranges and core areas than females, and both sexes showed a contraction in home-range and core area in fall leading up to the breeding season compared with summer. Heavier individuals had smaller core areas than lighter ones, suggesting access to higher quality habitat might be limited to those individuals with greater foraging experience and competitive ability. The size of the home-range or core area was not an important predictor of the rate of mass gain. A fine-scale spatio-temporal analysis of habitat use within the home-range provided evidence of intra-annual site fidelity at presumed foraging locations, suggesting predictably in prey distribution. Neither sex nor season were useful predictors for classifying behaviour. Rather, individual identity explained much of the variation in fine-scale behaviour. Understanding how upper-trophic level marine predators use space provides opportunities to explore the consequences of variation in foraging tactics and their success on fitness. Having knowledge of the drivers that shape this intraspecific variation can contribute toward predicting how these predators may respond to both natural and man-made environmental forcing.

中文翻译：

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高营养级海洋捕食者在精细范围内使用的性别差异。


海洋中猎物的分布在空间和时间上都是不均匀的。捕食者如何应对这种猎物的分散性可能会影响它们的觅食成功率，从而影响它们的身体状况。最近记录海洋动物精细运动的能力与结合时间维度的新颖的活动范围分析相结合，应该可以更好地了解个体如何利用不同的空间区域以及对觅食成功的影响。经过六年的研究，我们使用 T-LoCoH（时间本地凸包）家庭范围软件对来自 81 只灰海豹的存档 GPS（全球定位系统）数据进行建模，以研究空间和空间的精细时空利用。表观觅食努力的分布。根据回访频率（地点保真度）和访问持续时间（使用强度）对活动范围进行分类。广义线性混合效应模型用于检验关于觅食分布和行为的季节变化的假设，以及空间利用和状态在决定觅食成功方面的作用。雄性灰海豹比雌性拥有更大的活动范围和核心区域，并且与夏季相比，雄性灰海豹在繁殖季节前的秋季活动范围和核心区域均出现收缩。较重的个体比较轻的个体具有更小的核心区域，这表明获得更高质量的栖息地可能仅限于那些具有更多觅食经验和竞争能力的个体。活动范围或核心区域的大小并不是质量增加率的重要预测因素。对活动范围内栖息地利用的精细时空分析提供了假定觅食地点的年度内地点保真度的证据，表明猎物分布是可预测的。 性别和季节都不是对行为进行分类的有用预测因素。相反，个体身份解释了精细行为的大部分变化。了解上层营养级海洋捕食者如何利用空间，为探索觅食策略变化的后果及其对健康的成功提供了机会。了解形成这种种内变异的驱动因素有助于预测这些捕食者如何应对自然和人为的环境强迫。