Collaborative Research: BEST: The Trophic Role of Euphausiids in the eastern Bering Sea: Ecosystem Responses to Changing Sea-ice Conditions

Lessard 0732389大学。主要研究人员的主要假设是，海冰和相关食物资源的时间和覆盖范围的季节性和年际变化将导致食腐鱼的年龄结构、饮食历史和营养状况的差异，最终转化为产量和作为更高营养水平猎物的可用性的差异。提供资金量化重要黄鳝的年龄结构和饮食史，以及有关其消费和生长的详细信息，并将野外采集和分析与实验室饲养联系起来，进行年龄校准和船上饲养实验，以测试营养脂质标志物的有效性和保留情况以及食物资源的质量和数量。调查人员的目标包括：1。在季节和年际时间尺度上，确定气候驱动的海冰条件变化对主要黄鳝种类的脂质含量和脂质类别的潜在影响，从而确定营养状况和生殖潜力。了解不同空间（冰覆盖区、冰缘区和开放水域）和时间（季节和年际）猎物场变化下的食虫史、摄食率和采食策略。多种方法（如饲养实验、肠道含量分析）将用于验证和确定特定脂质膳食标记的保留。应用生物化学方法的最新进展来确定野地小蝽种群的年龄结构，以及气候变化对季节性和年际群体维持或中断的潜在影响。由阿拉斯加同事并行进行的实验室饲养将允许校准队列中的精确年龄。该项目是一个更大项目的一部分，旨在了解白令海东部陆架的综合生态系统，这是美国沿海水域的一个高产地区。这个生态系统是美国大部分商业渔业的家园，也为阿拉斯加的自给猎人和渔民提供了重要的资源。据信，食蚜虫是连接该地区浮游生物和鱼类资源的食物网中的关键一环。了解这些生物的生态对于了解商业和自给渔业如何应对不断变化的环境至关重要。

Lessard 0732389Univ. of Washington The principal investigators' primary hypothesis is that seasonal and interannual variation in the timing and coverage of sea-ice and associated food resources will lead to differences in age structure, diet history and nutritional condition for euphausids, which ultimately translate into differences in production rates and availability as prey to higher trophic levels. Funds are provided to quantify the age structure and diet history of important euphausids together with detailed information on their consumption and growth and to link field collections and analysis with laboratory rearing for age calibrations and shipboard feeding experiments to test the validation and retention of trophic lipid markers as well as the quality and quantity of food resources.The investigators' objectives include:1. To determine the potential impact of climate driven changes in sea-ice conditions on lipid content and lipid classes in major euphausid species and thus nutritional condition and reproductive potential over seasonal and interannual time scales.2. To understand the feeding history, feeding rates and grazing strategies of euphausids under changing spatial (i.e. ice-covered, ice-edge, and open water zones) and temporal (i.e. seasonal and interannual) prey fields. Multiple approaches (i.e. feeding experiments, gut content analysis) will be used for validation and determination of retention of specific lipid dietary markers.3. To apply recent advances in biochemical approaches to determine the age structure in field populations of euphausids and the potential effects of climate change on maintenance or disruption of cohort populations seasonally and interannually. Laboratory rearing conducted in parallel by Alaskan colleagues will allow calibrating precise ages in cohorts.This project is part of a larger program designed to develop understanding of the integrated ecosystem of the eastern Bering Sea shelf, a highly productive region of US coastal waters. This ecosystem is home to a major portion of the commercial fisheries of the US and also provides significant resources to subsistence hunters and fisherman of Alaska. Euphausids are believed to be a critical link in the food web connecting plankton to fish resources in the region. Understanding the ecology of these organisms is critical to understanding how the commercial and subsistence fisheries may respond to a changing environment.