RAPID: Understanding the unprecedented anchovy response to warm-water conditions in the California Current

RAPID：了解加州洋流中凤尾鱼对暖水条件前所未有的反应

• 批准号: 2053719
• 负责人: Brice Semmens
• 金额: $ 20万
• 依托单位: University of California-San Diego Scripps Inst of Oceanography
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-11-01 至 2022-10-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2053719&HistoricalAwards=false
• 关键词: RAPID; Understanding; unprecedented; anchovy; response

Like many species of small pelagic marine fish, recruitment and productivity of Northern Anchovy fluctuate by orders of magnitude among years. When abundant, the anchovy support a wide range of marine species, including marine mammals, seabirds and a diverse group of marine fishes. Anchovy, which previously thrived during periods of cool-water temperatures and strong coastal upwelling, are currently booming with abundances far in excess of any historical record, even though the California Current Ecosystem is experiencing an unprecedented marine heat wave. This unexpected occurrence challenges the most basic understanding of the mechanisms driving population dynamics in the species. This project is investigating the effects of trophic relationships on population productivity by capitalizing on the immediate research opportunity afforded by the novel, yet ephemeral, state of a local marine heat wave. Findings from the work are being used to develop a mechanistic model of coastal pelagic fish population dynamics generally, and anchovy dynamics in particular. Funded field and lab work are supporting opportunities for undergraduate training and research, and are generating open-access data that serve the research and teaching/training communities into the future.This RAPID project augments the scheduled Fall research cruises jointly run by the California Cooperative Oceanic Fisheries Investigation and the California Current Ecosystem Long-Term Ecological Research programs. Together, these programs conduct regional oceanographic surveys that include anchovy spawning grounds and larval nursery areas. The RAPID-augmented sampling is designed to test the emerging hypothesis that anchovy populations are trophodynamically mediated at the larval stage, whereby high recruitment results from increased trophic transfer efficiency from the base of the food web. Larval diets and prey selection analyses are being paired with amino acid compound-specific isotope analysis (δ15N) of the larvae and prey field to generate detailed information on larval trophic ecology. Larval diets and plankton community structure are being related to available data on upwelling and productivity to assess environmental and biological drivers to trophic transfer efficiency. Collectively, these analyses are revealing how food chain length is regulated at the larval level through prey selection, at the prey level through community composition, and at the base of the food chain via coastal upwelling and primary production. Furthermore, this project is establishing whether the current trophic level of anchovy larvae is equal to that of historic population booms and if this is the result of favorable feeding conditions throughout their habitat. Findings from the study are generating a mechanistic understanding of the trophic underpinnings of small pelagic fish population productivity in coastal upwelling systems.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

像许多小型中上层海洋鱼类一样，北方凤尾鱼的补充量和生产力在几年间波动数量级。当数量丰富时，凤尾鱼支持广泛的海洋物种，包括海洋哺乳动物、海鸟和各种海洋鱼类。尽管加州目前的生态系统正在经历一场前所未有的海洋热浪，但凤尾鱼之前在凉水温度和强烈的沿海上升流时期蓬勃发展，目前正在蓬勃发展，其丰度远远超过任何历史记录。这一意想不到的事件挑战了对该物种种群动态驱动机制的最基本理解。这个项目正在调查营养关系对种群生产力的影响，方法是利用当地海洋热浪这种新颖而短暂的状态提供的直接研究机会。这项工作的结果正被用来开发沿海中上层鱼类种群动态的一般机制模型，特别是凤尾鱼种群动态。资助的实地和实验室工作正在支持本科生培训和研究的机会，并正在产生开放获取的数据，这些数据将服务于未来的研究和教学/培训社区。这个快速项目增加了由加州合作海洋渔业调查和加州当前生态系统长期生态研究计划联合运营的预定秋季研究巡航。这些项目一起进行区域海洋调查，其中包括凤尾鱼产卵场和幼体育苗区。快速扩大抽样的目的是检验一个新出现的假说，即凤尾鱼种群在幼体阶段是营养动力学中介的，即从食物网底部增加营养转移效率会导致高招募。正在将幼虫饲料和猎物选择分析与幼虫和猎物领域的氨基酸化合物特定同位素分析(δ15N)配对，以产生有关幼虫营养生态的详细信息。幼虫饲料和浮游生物群落结构正在与关于上升流和生产力的现有数据相关，以评估环境和生物驱动因素对营养转移效率的影响。总体而言，这些分析揭示了食物链长度是如何通过猎物选择在幼虫水平上调节的，在猎物水平上通过群落组成调节的，通过沿海上升流和初级生产在食物链的底部调节的。此外，该项目正在确定凤尾鱼幼虫目前的营养水平是否等于历史上种群激增的水平，以及这是否是整个栖息地有利的摄食条件的结果。这项研究的结果是从机械上理解沿海上升流系统中小型中上层鱼类种群生产力的营养基础。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。