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

像许多种类的小型中上层海洋鱼类，招聘和生产力的北方鳀鱼波动的数量级之间的年份。当数量丰富时，鱼类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。尽管加州当前生态系统正在经历前所未有的海洋热浪，但以前在水温较低和沿海涌升强烈的时期蓬勃发展的凤尾鱼目前的数量远远超过任何历史记录。这种意外的发生挑战了对该物种种群动态驱动机制的最基本理解。 该项目正在调查营养关系对人口生产力的影响，通过利用当地海洋热浪的新颖但短暂的状态所提供的直接研究机会。这项工作的结果正被用来制定一个沿海中上层鱼类种群动态，特别是浮游鱼类动态的机械模型。资助的实地和实验室工作是本科生培训和研究的支持机会，并产生开放获取的数据，服务于研究和教学/培训社区到future.This RAPID项目增强了预定的秋季研究巡航联合运行的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。这些项目共同进行区域海洋学调查，包括鲑鱼产卵场和幼虫育苗区。快速扩增取样的目的是测试新出现的假设，即在幼虫阶段，高招聘的结果，从食物网的基础营养转移效率增加的营养介导的寄生虫种群。幼虫饮食和猎物选择分析与幼虫和猎物领域的氨基酸化合物特异性同位素分析（δ 15 N）配对，以产生关于幼虫营养生态学的详细信息。幼虫的饮食和浮游生物群落结构正在与现有的数据上升流和生产力，以评估环境和生物驱动因素的营养转移效率。总的来说，这些分析揭示了食物链长度是如何在幼虫一级通过猎物选择，在猎物一级通过社区组成，并通过沿海涌升和初级生产在食物链的基础上进行调节。此外，该项目正在确定目前的营养水平是否与历史上的人口激增相等，以及这是否是整个栖息地有利的喂养条件的结果。 这项研究的结果产生了一个机械的理解的营养基础的小型中上层鱼类种群的生产力在沿海涌升system.This奖项反映了NSF的法定使命，并已被认为是值得通过使用基金会的智力价值和更广泛的影响审查标准进行评估的支持。

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.