Ecology of pinnipeds

我研究的长期目标是了解形成鳍足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和雌性灰海豹在生态学上的巨大差异。由于许多海洋哺乳动物和海鸟表现出类似于灰海豹的大小二型性，我们在灰海豹中发现的性别特异性差异可能很常见。我们还证明了显着的年龄相关的差异，雌性灰海豹的生殖性能，包括衰老的有力证据。在接下来的五年里，我和我的学生计划研究随着时间的推移，灰海豹雌性内部和之间的生殖能力的变化来源。我们还计划测试有关老年女性生殖能力下降的行为和生理机制的假设（即，30岁以上）。在大型哺乳动物中，后代的大小通常被用作雌性和后代适应性的代表，但这一假设很少在海洋食肉动物中得到验证。我们有五个队列样本断奶时的体型数据，并将使用招募时的体型和年龄、早期生殖成功率。有证据表明，饮食中相当大的个体差异被个体间的平均值所掩盖。我们将使用脂肪酸特征分析来研究饮食中个体差异的相对重要性，从而更好地了解饮食生态位宽度的这些组成部分。最后，我计划调查个体发育觅食行为的灰海豹使用模型适合Argos卫星定位数据。这项研究的结果对保护和管理鳍足类动物和我们的理解的重要性，大型海洋食肉动物的生态系统结构和功能的自上而下的影响的影响。

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.