Collaborative Research: BEST Synthesis: Integration and modeling of spatial-temporal variation in vital rates for euphausiids in eastern Bering Sea: Implications for demographics

磷虾(Euphausiids)是连接东白令海低营养层与鱼类的关键纽带，但对Euphausiids的生长和生命速率的了解非常有限。解决这些差距的基本信息一直是BEST-BSIERP实地计划的一个重要重点，该计划收集了关于几个真毛虫物种的个体生长率和放牧的空间上的明确信息。相关活动正在利用新的生物化学方法解决大范围的年龄结构问题。为了最好地利用这些多个数据集，提供了资金，用于集中努力整合和综合这些数据，以估计不同区域(内、中、外陆架)的增长和生命率，并建立Euphausiid种群动态模型，以了解其人口结构。指数将(1)描述与不同水文条件有关的真姬鼠分布的空间变化，(2)合成其人口结构的空间变化，包括年龄和长度频率，(3)模拟真姬鼠的种群动态和初级生产，(4)利用空间结构的统计模型研究捕食可能如何影响生命速率，以及(5)对两个重要物种的生活史和种群动态进行比较：分布更广泛的物种，拉氏梭子虫和主要栖息在外架上的物种，长臂猿。结果将在不同的水文条件可能如何通过改变其生长和生命率来影响Euphausiid种群的人口结构的背景下进行综合。了解不同的水文条件如何影响它们的生长、生命速率和人口结构，将有助于更好地理解这些条件的大范围变化将如何影响真海豚种群，以及对较高营养水平的潜在影响。白令海生态系统提供了美国大约一半的商业海鲜上岸，以及自给自足的渔民的重要资源。这些储量的主要波动在过去曾发生过，并与观测到的白令海水文条件的变化有关。该项目的结果将表明白令海的食物网可能会因这种水文变化而改变的机制。

Euphausiids (krill) are a critical link connecting lower trophic levels to fish in the eastern Bering Sea, yet knowledge of euphausiid growth and vital rates is very limited. Fundamental information to address these gaps has been an important focus of the BEST-BSIERP field program, which has collected spatially explicit information on individual growth rates and grazing for several euphausiid species. Related activities are addressing broad scale age structure using new biochemical approaches for euphausiids. To make the best use of these multiple data sets, funds are provided for a focused effort to integrate and synthesize these data to estimate growth and vital rates for different regions (inner, middle, and outer shelf), and model euphausiid population dynamics to understand their demographic structure. The PIs will (1) describe spatial variations in the distribution of euphausiids in relation to different hydrographic conditions, (2) synthesize spatial variations in their demographic structure, including age and length frequency, (3) model euphausiid population dynamics and secondary production, (4) examine how predation may impact vital rates using spatial-structured statistical models, and (5) produce a comparison of life history and population dynamics of two important species: a species with broader distribution, Thysanoessa raschii, and a species primarily resident over the outer shelf, T. longipes. Results will be synthesized in the context of how the varying hydrographic conditions may impact the demographic structures of euphausiid populations by changing their growth and vital rates. Understanding how varying hydrographic conditions influence their growth and vital rates and demographic structure will lead to better understanding of how large scale changes in these conditions would influence euphausiid populations and potential impacts on higher trophic levels.The Bering Sea ecosystem provides roughly half the commercial seafood landings in the United States, as well as significant resources for subsistence fishermen. Major fluctuations in these stocks have occurred in the past and been associated with variations in the observed hydrographic conditions of the Bering Sea. The results of this project will indicate mechanisms by which the food web of the Bering Sea may be modified by such hydrographic variations.