Life history variation in pinnipeds

鳍足类生活史变异

• 批准号: RGPIN-2018-05403
• 负责人: Bowen, William
• 金额: $ 4.08万
• 依托单位: Dalhousie University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2022
• 资助国家: 加拿大
• 起止时间: 2022-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=745621
• 关键词: Life; history; variation; pinnipeds

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.

我研究的长期目标是了解形成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，我和我的学生计划建立在我们对灰海豹（Halichoerus grypus）生活史和觅食生态学的长期研究基础上。在繁殖性能的变异性内和个体之间在其生殖生命已被记录为相对较少的大型长寿脊椎动物。性状的平均估计值掩盖了个体对环境变异性和趋势的反应中潜在的重要变异性。我们计划继续从>1700只个体标记的已知年龄雌性动物中收集长期数据（2017年>30年），以研究生殖能力和存活率个体差异的内在和外在来源，并评估这种差异对后代存活率和断奶时大小的影响。这些数据还将用于检验性能异质性的性质（固定vs动态）以及首次生育年龄与终生生殖成功率之间的关系。我们还将使用永久标记的男性（~600）和女性（如上所述）的目击历史来测试有关性别特异性发病和生存率和生殖衰老的假设，以及生存模式如何随人口丰度和环境变化而变化。虽然后代的大小经常被用作雌性和后代适合度的代表，但这一假设很少在大型长寿（>20岁）哺乳动物中得到验证。测量了1998年至2002年出生的约2400只永久标记的灰海豹幼崽和2014年至2016年出生的另外2100只幼崽的大小和其他后代特征。我们将测量这些幼仔幸存者招募时的大小和年龄，以测试后代大小、存活率和长期生殖能力之间的关系。 我们将使用配备两个三轴加速度计的灰海豹的精细尺度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。沿着动物携带的摄像机，我们试图更好地了解觅食的空间和时间模式，在上层营养级海洋捕食者。