The ecology of forage fish species and interactions with marine predators

饲料鱼的生态学及其与海洋捕食者的相互作用

• 批准号: RGPIN-2014-06290
• 负责人: Davoren, Gail
• 金额: $ 3.28万
• 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: 2018
• 资助国家: 加拿大
• 起止时间: 2018-01-01 至 2019-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=648753
• 关键词: ecology; forage; fish; species; interactions

The long-term goals of my research program are to investigate the basic ecology of forage fish species and how this shapes the biology of predators in marine ecosystems of northern Canada. Capelin, a small minnow-like fish, is the focal forage fish species that preys on many invertebrates and is in turn preyed on by most large predators, including cod, whales and seabirds in the Northwest Atlantic. Capelin provide essential linkages for energy transfer among trophic levels and, thus, are often thought to mediate ecosystem-level changes. In previous NSERC-funded research, I discovered capelin spawning in deep water (demersal) habitat in coastal Newfoundland, where this species is primarily thought to spawn on beaches. I also provided the first direct evidence that capelin select between warm, beach and cool, demersal habitats based on habitat-specific temperature, suggesting a higher occupation of demersal habitat with predicted climate warming. Although eggs develop normally and larvae emerge from demersal habitat, this habitat is not thought to contribute individuals to the spawning population. My first short-term objective is to elucidate the relative contribution of demersal and beach habitats to recruitment using cutting-edge techniques to quantify otolith microchemistry (i.e. laser ablation inductively coupled plasma mass spectrometry) as a natural tag of natal origin. This requires quantifying habitat-specific otolith chemical signatures (e.g., Sr, Ba) in the core region, representing the period before and immediately post-hatch, by integrating long-term measures of temperature, salinity and water chemistry along with otolith chemistry from larvae raised within each habitat and under controlled thermohaline and chemical conditions in the lab. This will also provide insight into connectivity and metapopulation dynamics, which are critical for effective management and conservation of highly mobile marine fish. As most vertebrate predators rely on capelin as prey in Newfoundland, my second objective is to study the individual-level plasticity of predator foraging strategies to changing capelin density and behaviour. My previous NSERC-funded research revealed that multiple marine predator species aggregate in high abundances (`biological hotspot') near a cluster of annually persistent demersal spawning sites, likely owing to augmented prey encounter rates with minimal search efforts. I will integrate recently miniaturized animal-borne tracking devices to examine individual-level foraging behaviour of predators with survey-based shifts in capelin density and behaviour. Survey data also will be investigated to determine predator preferences for different capelin aggregation types to clarify functional relationships between predators and prey. Owing to the high conservation value of this multispecies hotspot, my third objective is to investigate whether similar hotspots associated with capelin demersal spawning sites occur elsewhere in Newfoundland, with the ultimate goal of identifying important areas to protect. Several long-term data sets will be integrated with short-term hypothesis-driven research, forming the basis of many inter-related, field-based student theses. Overall, this will improve the accuracy of capelin year class strength models and allow the development of ecosystem-based harvest rules for this and other forage fish species. This will further develop scientific theories of predator-prey population dynamics to maintain the structure and function of northern marine ecosystems under future fisheries practices and climate change.

我的研究计划的长期目标是调查饲料鱼类的基本生态学，以及这是如何塑造加拿大北方海洋生态系统中的捕食者的生物学。毛鳞鱼是一种小型的小鱼，是捕食许多无脊椎动物的主要饲料鱼类，反过来又被大多数大型捕食者捕食，包括西北大西洋的鳕鱼、鲸鱼和海鸟。毛鳞鱼为营养级之间的能量转移提供了必要的联系，因此，通常被认为是调解生态系统水平的变化。在以前的NSERC资助的研究中，我发现毛鳞鱼在纽芬兰沿海的深水（底层）栖息地产卵，这种物种主要被认为是在海滩上产卵。我还提供了第一个直接的证据，毛鳞鱼选择温暖，海滩和凉爽，底层栖息地的基础上，特定的栖息地的温度，这表明一个较高的占领底层栖息地与预测的气候变暖。虽然卵发育正常，幼虫出现在底栖栖息地，但这种栖息地被认为不会为产卵种群提供个体。我的第一个短期目标是阐明底栖和海滩栖息地的相对贡献招聘使用尖端技术，以量化耳石微化学（即激光消融电感耦合等离子体质谱）作为纳塔尔起源的天然标签。这需要量化生境特异性耳石化学特征（例如，Sr，Ba）在核心区域，代表孵化前和孵化后立即，通过整合长期的温度，盐度和水化学沿着与耳石化学的措施，从幼虫提出的每个栖息地和控制温盐和化学条件下，在实验室。这也将提供对连通性和集合种群动态的深入了解，这对于有效管理和保护高度移动的海洋鱼类至关重要。由于大多数脊椎动物的捕食者依赖于毛鳞鱼作为猎物在纽芬兰，我的第二个目标是研究个人层面的可塑性捕食策略，以改变毛鳞鱼的密度和行为。我以前的NSERC资助的研究表明，多个海洋捕食者物种聚集在高丰度（“生物热点”）附近的一组每年持续的底层产卵地点，可能是由于增加猎物遇到率与最小的搜索努力。我将整合最近小型化的动物携带的跟踪设备，以检查个人层面的捕食者的觅食行为与调查为基础的变化，毛鳞鱼的密度和行为。调查数据也将进行调查，以确定捕食者的偏好不同的毛鳞鱼聚集类型，以澄清捕食者和猎物之间的功能关系。由于这个多物种的热点，我的第三个目标是调查是否与毛鳞鱼底层产卵场发生在纽芬兰其他地方类似的热点，确定重要的地区保护的最终目标。几个长期的数据集将与短期假设驱动的研究相结合，形成许多相互关联的，基于领域的学生论文的基础。总的来说，这将提高毛鳞鱼年级强度模型的准确性，并允许开发基于生态系统的收获规则和其他饲料鱼类。这将进一步发展捕食者-被捕食者种群动态的科学理论，以便在未来渔业做法和气候变化的情况下维持北方海洋生态系统的结构和功能。