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

焦点饲料鱼的生态及其对海洋捕食者的影响

• 批准号: RGPIN-2019-05385
• 负责人: Davoren, Gail
• 金额: $ 2.4万
• 依托单位: University of Manitoba
• 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=744720
• 关键词: ecology; focal; forage; fish; its

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.

我的研究计划的长期目标是调查关键饲料鱼类物种的招募动态，以及这些动态如何塑造加拿大北部海洋生态系统的营养和食物网相互作用。与陆地系统不同，海洋食物网在“黄蜂腰”控制下是独一无二的，其中大部分能量通过少数饲料鱼类汇集，使这些物种对能量流动至关重要。毛鳞鱼是北方海洋生态系统中捕食许多无脊椎动物的主要饲料鱼类，也是大多数大型捕食者（即鱼类、鲸鱼、海鸟）的猎物，因此，毛鳞鱼通常被认为是生态系统水平变化的中介。这些短寿鱼类的特点是种群大小的自然波动很大（~±40%），这是由存活繁殖或招募的个体数量的年度变化所驱动的。招聘动态背后的机制往往不清楚，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加拿大北极地区毛鳞鱼幼虫存活的生物物理因素（即猎物和捕食者密度、温度、盐度），在过去的二十年里，这种亚北极物种的丰度急剧增加。在纽芬兰沿海地区，我也将量化产卵栖息地和地区对纽芬兰沿海地区招募的相对贡献，使用尖端的耳石化学技术来确定产卵毛鳞鱼的出生栖息地。由于大多数脊椎动物捕食者依赖毛鳞蛋白作为猎物，我的第二个短期目标是利用实验方法，在不同的猎物和捕食者条件下操纵群体觅食的成本和收益，以揭示生态位分配背后的行为机制。此外，我将研究多物种捕食者对猎物变化的觅食反应，以及多维生态位重叠。同时，研究捕食者-猎物关系、捕获猎物过程中的物种相互作用和动态猎物制度下多种海洋捕食者生态位重叠，将确定捕食者之间的相互作用是否掩盖了捕食者-猎物的功能关系，并提供对食物网对不同猎物生物量的反应以及这些反应的机制的见解。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、基于实地的学生论文的基础。总体而言，该研究项目支持高水平的HQP（3名现场助理学士，5名荣誉学士，5名硕士，3名博士），并将增强我们在不断变化的海洋气候下维持北部海洋生态系统长期生产力的能力，以维持渔业产量和保护海洋生物多样性。