US GLOBEC: Productivity of Calanus Finmarchicus and Fluctuations in Growth and Survival of Cod and Haddock Larvae on Georges Bank: A Synthesis of Observations and Modeling

9806565 werner本项目提出了一种假说，将乔治海岸桡足类动物生产力的时空变化与鳕鱼和黑线鳕幼虫的生长和存活联系起来。该研究综合了美国CLOBEC乔治滩计划之前和期间的调查结果和过程观察，并使用最近开发的鳕鱼和黑线鳕幼虫生物物理个体模型（IBM）来研究桡足类猎物产量变化的重要性，这些变化相对于其他因素，包括环流、温度、湍流和光照，这些因素可能会影响到乔治滩鱼类种群的成功或失败。乔治滩的鳕鱼和黑线鳕幼虫主要以优势桡足类的卵和鳃为食。因此，垂直整合桡足动物的产蛋量（VIP），以卵数m-2 d-1或mg-C m-2 d-1表示)是幼虫鱼猎物日产量的一个指标。george Bank项目早期阶段的研究表明，在三个月的时间里，george Bank南侧的桡足动物VIP总量可以变化1-2个数量级；其中，对桡足类总VIP格局有主导影响的是金雀鳝。这些数据表明，桡足类和总桡足类产卵量的变化可能是影响乔治滩鱼类幼虫猎物可得性的主要因素。然而，人们对总产蛋量和Calanus产蛋量的年际变化和空间结构的了解甚少。沃纳博士和他的同事们认为，乔治河岸的产蛋模式和总量每年都有很大的变化。如果在东北峰和南翼的某些年份为卡罗纳斯雌鱼提供高丰度和充足的营养，幼鱼的食物条件可能会增加一个数量级或更多，从而显著提高它们的生长和存活率。基于这些考虑，研究者提出了以下三部分假设：(1)总VIP（所有优势桡足类）的空间、季节和年际变化很大（即数量级）；(2)VIP与东侧和南侧鱼类幼鱼的生长和存活存在显著关系；(3)黄颡鱼（Calanus finmarchicus）生产力的变异影响着乔治岸鳕鱼和黑线鳕幼鱼的生长和存活。这些假设将通过综合和建模研究进行验证。

9806565WernerThis project addresses a hypothesis linking spatial/temporal variability in copepod productivity and the growth and survival of cod and haddock larvae on Georges Bank. It represents a synthesis of survey results and process observations conducted prior to and during the U.S. CLOBEC Georges Bank Program, and uses a recently-developed biophysical, individual-based model (IBM) of cod and haddock larvae to investigate the importance of variation in copepod prey field production relative to other factors, including circulation, temperature, turbulence and light, that potentially contribute to the success or failure of recruitment into Georges Bank fish stocks.Cod and haddock larvae on Georges Bank feed primarily on the eggs and nauplii of the dominant copepod species. The vertically-integrated copepod egg production (VIP), in terms of eggs m-2 d-1 or mg-C M-2 d-1) is therefore an index of the daily production of larval fish prey. Research during earlier phases of the Georges Bank program showed that, over three-month periods, the total copepod VIP can vary by 1-2 orders of magnitude on the southern flank of Georges Bank; with Calanus finmarchicus being a dominant influence on the pattern of total copepod VIP.These data suggest that variability in Calanus and total copepod egg production is potentially a major influence on the availability of prey to fish larvae on Georges Bank. However, there is little knowledge about inter-annual variation in both the magnitude and spatial structure of total and Calanus egg production. Dr. Werner and associates suggest that the pattern and magnitude of total egg production on Georges Bank is highly variable from year to year. If a high abundance and sufficient nutrition for Calanus females is set up in some years on the northeast peak and southern flank, food conditions for fish larvae could increase by an order of magnitude or more, with consequent dramatic improvement in their growth and survival.Based on these considerations, the investigators put forward the following, three-part hypothesis: (1) the spatial, seasonal and inter-annual variation in the total VIP (all dominant copepods) is substantial (i.e., orders of magnitude), (2) there is a significant relationship between the VIP and growth and survival of fish larvae on the eastern and southern flanks and (3) variability in the productivity of Calanus finmarchicus influences the growth and survival of cod and haddock larvae on Georges Bank. The hypotheses will be tested by a combined synthesis and modeling study.