U.S.-GLOBEC: NWA Georges Bank. Factors determining early-life-stage survival & recruitment variability in N. Atlantic cod: a comparison bewteen NW Atlantic & Norwegian Sea

这项研究通过与卑尔根海洋研究所的挪威同事合作，比较了乔治海岸和挪威大陆架/巴伦支海的生态系统。目的是更好地了解鱼类种群和浮游动物之间的相互作用以及这些相互作用如何受到气候变率和变化的影响。这种理解将被纳入到成年阶段的鳕鱼招募模型中。总体假设是，鳕鱼和黑线鳕的招募是由卵和幼虫阶段的存活率变化决定的，这受到密度和栖息地依赖因素的限制。两个子假设断言（Ho1）苏格兰陆架水平流进入缅因湾，（Ho2）挪威海浮游动物丰富的水平流进入巴伦支陆架，增加了每个系统中鳕鱼/黑线鳕的幼虫生长和存活。该方法包括：1)在流域尺度上计算物理和生物场，以评估两个系统中局部效应与平流/上游效应的相对重要性。(2)在区域范围内实施拉格朗日模型，量化两个系统中的滞留和输送及其变异性；(3)建立基于个体的空间明确的幼鱼和幼鱼生长模型，结合观察到的猎物数据，将提供两个系统的生长速率。(4)建立一套影响生命早期保留/转运、生长和生存的因子和过程的指标或替代指标。(5)建立将成年人口的动态与影响招募的物理和生物因素联系起来的模型。将西北大西洋/乔治海岸与挪威海系统进行相互比较，可以对方法及其与其他地点的相关性进行概括。基于详细过程研究的指数的发展将用于发展、参数化和评价与商业上重要物种的成虫种群动态有关的杂交补充模型。所有结果都将在网上公开，以便感兴趣的学生、教师、科学家或资源管理者可以使用它们。

This study compares the ecosystems on Georges Bank and the Norwegian shelf/Barents Sea via a collaboration with Norwegian colleagues at the Institute of Marine Research (Bergen). The objective is to develop a better understanding of the interactions between fish populations and zooplankton and how these interactions are influenced by climate variability and change. This understanding will be incorporated into a model of cod recruitment through the adult stages.The overarching hypothesis is that recruitment of cod and haddock is determined by variability in survival during the egg and larval stages, which is constrained by density- and habitat-dependent factors. Two sub-hypotheses assert that (Ho1) advection of Scotian shelf water into the Gulf of Maine and (Ho2) advection of zooplankton-rich water from the Norwegian Sea into the Barents shelf increases larval cod/haddock growth and survival in each system. The approach includes: 1) Computation of physical and biological fields on a basin-scale to evaluate the relative importance of local vs. advective/upstream effects in the two systems. (2) Implementation of Lagrangian models within the regional domains to quantify retention and transport and their variability in the two systems; (3) Implementation of spatially-explicit individual-based models for larval and early juvenile fish growth which, when coupled with the observed prey data will provide growth rates in the two systems. (4) Development of asuite of indices or proxies for factors and processes affecting early-life retention/transport, growth and survival.(5) Development of models linking the dynamics of adult populations with physical and biotic factors affecting recruitment.The inter-comparison of the NW Atlantic/Georges Bank with the Norwegian Sea system, allows for a generalization of the approaches and their relevance to other locations. The development of indices based on the detailed process studies will be used to develop, parameterize and evaluate hybrid recruitment models linked to the dynamics of adult stocks of commercially important species. All results will be made publicly available on the web so that interested students, teachers, scientists or resource managers can make use of them.