Ecology of pinnipeds

我研究的长期目标是了解影响鳍脚类觅食和繁殖策略的进化和生态因素。我们已经证明了成年雄性灰海豹和雌性灰海豹在生态上的广泛差异。由于许多海洋哺乳动物和海鸟的体型与灰海豹相似，所以我们在灰海豹身上发现的性别差异可能是常见的。我们还证明了雌性灰海豹的繁殖性能与年龄有关的显著差异，包括强烈的衰老证据。在接下来的五年里，我和我的学生们计划研究灰海豹内和雌性灰海豹之间随着时间的推移繁殖性能的变异性来源。我们还计划测试关于行为和生理机制的假设，这些机制是导致老年女性(即那些30岁的女性)生殖能力下降的基础。在大型哺乳动物中，后代的大小经常被用来代表雌性和后代的健康状况，但这一假说很少在海洋食肉动物身上得到验证。我们有五个队列样本在断奶时大小的数据，并将在招募、早期繁殖成功时使用大小和年龄。有证据表明，饮食中相当大的个体差异被个体间的平均化所掩盖。我们将使用脂肪酸特征分析来检查饮食中内部和个体差异之间的相对重要性，从而更好地了解这些组成食物生态位宽度的因素。最后，我计划使用适合Argos卫星位置数据的模型来研究灰海豹觅食行为的个体发育。这项研究的结果对管脚类的保护和管理以及我们理解大型海洋食肉动物对生态系统结构和功能的自上而下影响的重要性具有重要意义。

The long-term objective of my research is to understand the evolutionary and ecological factors that have shaped the foraging and reproductive strategies of pinnipeds. We have demonstrated broad differences in the ecology of adult male and female grey seals. Because many marine mammals and seabirds express size dimorphism similar to grey seals, the kind of sex-specific differences we have found in grey seals may be common. We have also demonstrated pronounced age-related differences in reproductive performance of female grey seals, including strong evidence of senescence. During the next five years, my students and I plan to study sources of variability in reproductive performance within and among grey seal females over time. We also plan to test hypotheses about the behavioural and physiological mechanisms that underlie the decline in reproductive performance of older females (i.e., those >30 yr old). Offspring size is often used as a proxy for female and offspring fitness in large mammals, but this hypothesis has rarely been tested in marine carnivores. We have data on size at weaning for samples of five cohorts and will use size and age at recruitment, early reproductive success. There is evidence that considerable individual variation in diet is obscured by averaging across individuals. We will use fatty acid signature analysis to examine the relative importance of within vs. among individual variation in diet and thus to better understand these components of dietary niche width. Finally I plan to investigate the ontogeny of foraging behaviour in grey seals using models fit to Argos satellite locations data. The results of this research have implications for the conservation and management of pinnipeds and for our understanding of the importance of top-down effects of large marine carnivores on ecosystem structure and functioning.