The ecology of focal forage fish and its influence on marine predators

我的研究计划的长期目标是调查招聘动态的关键饲料鱼类，以及如何这些动态形状的营养和食物网的相互作用在加拿大北方的海洋生态系统。与陆地系统不同，海洋食物网受到独特的“蜂腰”控制，大部分能量通过少数饲料鱼类汇集，使这些鱼类对能量流动至关重要。毛鳞鱼是捕食许多无脊椎动物的焦点饲料鱼类，反过来又被大多数大型捕食者捕食（即，鱼类、鲸鱼、海鸟），因此，人们常常认为，海洋生物在北方海洋生态系统中起着调节生态系统变化的作用。这些短命鱼类的特点是种群规模的自然波动很大（约±40%），这是由存活繁殖或补充的个体数量的年度变化所驱动的。招募动态的基本机制往往不清楚，部分原因是缺乏假设驱动的研究。我的第一个短期目标是调查生物物理因素（即，猎物和捕食者的密度，温度，盐度）的基础毛鳞鱼幼虫生存在加拿大北极，在这个亚北极物种的丰度在过去二十年中急剧增加。在沿海纽芬兰，我也将量化的相对贡献的产卵栖息地和地区的招聘在沿海纽芬兰使用尖端的耳石化学技术，以确定产卵毛鳞鱼的纳塔尔地。由于大多数脊椎动物的捕食者依赖于毛鳞鱼作为猎物，我的第二个短期目标是操纵不同的猎物和捕食条件下的组觅食的成本和收益，使用实验方法，揭示生态位划分的行为机制。此外，我将调查捕食觅食反应的多个物种不断变化的猎物制度，沿着与多维生态位重叠。同时调查捕食者-猎物关系，物种之间的相互作用在猎物捕获和生态位重叠的多个海洋捕食者在动态的猎物制度将确定捕食者之间的相互作用是否掩盖捕食者-猎物的功能关系，并提供洞察食物网响应不同的猎物生物量沿着这些反应的机制。几个长期数据集将与短期假设驱动的研究相结合，形成相互关联的，基于领域的学生论文的基础。总的来说，这项研究计划支持高水平的HQP（3个B.Sc.现场助理，5个B.Sc.荣誉，5个M.Sc.，3 Ph.D.），并将提高我们维持北方海洋生态系统长期生产力的能力，以便在不断变化的海洋气候下维持渔业产量和保护海洋生物多样性。

The long-term objective of my research program is to investigate recruitment dynamics of key forage fish species and how these dynamics shape trophic and food web interactions in marine ecosystems of northern Canada. Unlike terrestrial systems, marine food webs are uniquely under “wasp-waist” control, whereby most energy is funnelled through a few forage fish species, making these species critical to energy flow. Capelin is the focal forage fish species that preys on many invertebrates and is in turn preyed on by most large predators (i.e., fish, whales, seabirds) in northern marine ecosystems and, thus, is often thought to mediate ecosystem-level changes. These short-lived fish species are characterized by high natural fluctuations in population size (~±40%), driven by annual variability in the number of individuals surviving to reproduce, or recruitment. Mechanisms underlying recruitment dynamics are often unclear, in part due to a lack of hypothesis-driven research. My first short-term objective is to investigate the bio-physical factors (i.e., prey and predator densities, temperature, salinity) underlying capelin larval survival in the Canadian Arctic, where the abundance of this sub-Arctic species has increased dramatically in the last two decades. Within coastal Newfoundland, I also will quantify the relative contribution of spawning habitats and regions to recruitment in coastal Newfoundland using cutting-edge otolith chemistry techniques to identify the natal habitat of spawning capelin. As most vertebrate predators rely on capelin as prey, my second short-term objective is to manipulate the costs and benefits of group foraging under varying prey and predator conditions, using an experimental approach, to reveal the behavioural mechanisms underlying niche partitioning. Additionally, I will investigate predator foraging responses of multiple species to changing prey regimes, along with multi-dimensional niche overlap. Simultaneously investigating predator-prey relationships, species interactions during prey capture and niche overlap of multiple marine predators under dynamic prey regimes will determine whether interactions among predators obscure predator-prey functional relationships, and provide insight into food web responses to varying prey biomass along with mechanisms underlying these responses. Several long-term data sets will be integrated with short-term hypothesis-driven research, forming the basis of inter-related, field-based student theses. Overall, this research program supports a high level of HQP (3 B.Sc. field assistants, 5 B.Sc. Honours, 5 M.Sc., 3 Ph.D.), and will enhance our ability to maintain the long-term productivity of northern marine ecosystems to sustain fisheries yields and conserve marine biodiversity under a changing ocean climate.