Life history variation in pinnipeds

我研究的长期目标是了解影响海豹觅食和繁殖策略的进化和生态因素。在接下来的五年里，我和我的学生们计划在我们对灰海豹(Halichoerus Grypus)生活史和觅食生态学的长期研究的基础上再接再厉。在相对较少的大型长寿脊椎动物中，记录了个体内和个体之间在其生殖生命过程中生殖性能的可变性。对特征的平均估计掩盖了个体对环境变化和趋势的反应中潜在的重要变异性。我们计划继续收集1700只单独标记的已知年龄雌性个体的长期数据(2017年为30年)，以调查繁殖性能和存活的个体变异的内在和外部来源，并评估这种变异对后代存活和断奶时大小的影响。这些数据还将被用来测试性能的异质性(固定和动态)的性质，以及第一次出生的年龄和终身生殖成功之间的关系。我们还将使用永久标记的雄性(约600只)和雌性(如上所述)的目击历史来测试关于特定性别的发病和存活率和生殖衰老的假设，以及生存模式如何随着种群丰度和环境变异性的变化而变化。虽然后代的大小经常被用来代表雌性和后代的健康状况，但这一假设很少在大型、长寿(&gt；20岁)的哺乳动物身上得到验证。对1998年至2002年出生的约2400只永久标记灰海豹幼崽和2014年至2016年出生的2100只幼崽的体型和其他后代特征进行了测量。我们将测量这些幼崽招募时的大小和年龄，以测试后代大小、存活率和长期繁殖性能之间的关系。我们将使用装有两个三轴加速度计的灰色海豹的精细GPS轨迹来开发算法来区分行为，包括觅食，以验证从状态空间运动模型估计的行为状态。与动物携带的相机一起，我们试图更好地了解上层营养级海洋捕食者觅食的空间和时间模式。

The long-term objective of my research is to understand the evolutionary and ecological factors that have shaped the foraging and reproductive strategies of seals. During the next five years, my students and I to plan build upon our long-term studies of life history and foraging ecology of grey seals (Halichoerus grypus). Variability in reproductive performance within and among individuals over their reproductive life has been documented for relatively few large long-lived vertebrates. Mean estimates of traits obscure potentially important variability in the response of individuals to environmental variability and trends. We plan to continue the collection of long-term data (>30 years in 2017) from >1700 individually marked, known-age females to investigate intrinsic and extrinsic sources of individual variability in reproductive performance and survival and to evaluate the consequences of this variability on offspring survival and size at weaning. These data will also be used to test for the nature of heterogeneity (fixed vs dynamic) in performance and the relationship between age at first birth and lifetime reproductive success. We will also use the sighting histories of permanently marked males (~600) and females (as above) to test hypotheses concerning sex-specific onset and rate of survival and reproductive senescence and how patterns of survival vary with changes in population abundance and environmental variability. Although offspring size is often used as a proxy for female and offspring fitness, this hypothesis has rarely been tested in large, long-lived (>20 yr) mammals. Size and other offspring traits were measured for about 2400 permanent-marked grey seals pups that were born from 1998 to 2002 and another 2100 pups from 2014 to 2016. We will measure size and age at recruitment of the survivors of those pups to test the relationship between offspring size, survival, and long-term reproductive performance. We will use fine-scale GPS tracks from grey seals fitted with two tri-axial accelerometers to develop algorithms to distinguish behaviours, including foraging, to validate behavioural states estimated from state-space movement models. Along with animal-borne cameras we seek to better understand the spatial and temporal pattern of foraging in an upper trophic-level marine predator.