Collaborative Research: US GLOBEC: Predation Impacts on Target Specie: Roles of Frontal Proceses and Small Predator Species

9806465 Madin GLOBEC Georges Bank计划旨在了解决定四种目标物种--幼鳕鱼和黑线鳕及其主要饲料猎物--桡足类Calanusfinmarchicus和Pseudocalanus spp种群动态的物理和生物过程。这些过程中的核心是捕食无脊椎动物和鱼类捕食者对这四个物种，本研究的目的是描述和量化的这种来源的mortality.The方法结合信息的丰富性和共生的捕食者和目标猎物物种乔治银行，来自持续的大规模调查，与新的数据喂养的特异性和利率的主要捕食者物种。在第一阶段和第二阶段，Madin，Sullivan和Bollens博士使用肠道内容物分析（通过显微镜和免疫测定）和饲养实验（船上和实验室，在小容器和围隔中）来获得饲养数据。 前两个阶段的实地取样侧重于分层效应（1995年）和水和生物的来源、保留和损失（1997年）。 在第三阶段，他们将（1999年）把实地工作引向有关锋面区域对目标物种及其捕食者的运输、聚集和相互作用的影响的问题。常规采样将辅以视频系统，以检测大型凝胶状捕食者。 对浮游生物群落动态研究的重要新贡献将是确定杂食性桡足类在限制草食动物生产中的作用，以及湍流在控制凝胶状捕食者捕食率中的作用的实验研究。乔治银行的物理和水文环境为目标物种及其捕食者的生物相互作用奠定了基础。该银行的水深和环流模式及其周围创建锋区的北部和南部边界，沿着其60米等深线之间的混合良好的中央脊和季节分层的南部侧翼。最后一个区域，潮汐混合锋，划分了两个在水文学和生物学方面非常不同的区域。 这些研究人员将在1999年的两次航行中在这一前沿开展工作，以确定沿沿着和穿越前沿的猎物和捕食者的分布和数量、前沿动态对聚集和相互作用的影响以及生物体从一边到另一边的交换。在Crest和Flank区域，他们在以前的过程研究中集中了精力，目标物种和主要捕食者之间的发生似乎有关键的重叠。锋面的湍流、辐合和交换对不同捕食生物有不同的影响。长期了解乔治银行系统的关键是开发全面的物理-生物模型。这项研究应作出重大贡献，这些模型的捕食死亡率是特定的季节，位置，物种，和主要的捕食者，阶段和密度的猎物的数据。

9806465MadinThe GLOBEC Georges Bank program is seeking to understand the physical and biological processes which determine the population dynamics of four target species -- larval cod and haddock, and their main forage prey, the copepods Calanusfinmarchicus and Pseudocalanus spp. Central among these processes is predation by invertebrate and fish predators on these four species, and the objective of this study is the description and quantification of this source of mortality.The approach combines information on the abundance and co-occurrence of predators and target prey species on Georges Bank, derived from the continuing Broad Scale Survey, with new data on feeding specificity and rates of the principal predator species. During Phases I and II, Drs. Madin, Sullivan and Bollens have used both gut-contents analysis (by microscopy and with immuno-assays) and feeding experiments (shipboard and laboratory, in small containers and mesocosms) to obtain feeding data. The field sampling during the first two Phases focused on the themes of stratification effects (1995) and source, retention and loss of water and organisms (1997). In Phase III they will direct field efforts (in 1999) to questions concerning effects of frontal regions on the transport, aggregation and interaction of target species and their predators. Conventional sampling will be supplemented with a video system to detect large gelatinous predators. Significant new contributions to the study of plankton community dynamics will be identification of the role of omnivorous copepods in limiting production of herbivores, and experimental studies of the role of turbulence in controlling predation rates of gelatinous predators.The physical and hydrographic environment of Georges Bank sets the stage for the biological interplay of target species and their predators. The bathymetry of the Bank and the pattern of circulation on and around it create frontal regions on its north and south boundaries, and along its 60 m isobath, between the well-mixed central Crest and the seasonally stratified southern Flank. This last region, the tidal mixing front, divides two areas which are very different in terms of hydrography and biology. These researchers will work at this front on two cruises in 1999, to determine the distribution and abundance of prey and predators along and across the front, the effect of frontal dynamics on aggregation and interaction, and the exchange of organisms from one side to the other. The Crest and Flank regions are where they have concentrated efforts in previous process studies, and where there appears to be a critical overlap in occurrence between target species and their main predators. Turbulence, convergence and exchange associated with the front may have different effects on predators with different feeding biologies. The key to long-term understanding of the Georges Bank system is development of comprehensive physical-biological models. This study should make a major contribution to these models with data on predation mortality which is specific to season, location, species, and for principal predators, stage and density of the prey.