Distribution and Survival of Cod Larvae in Relation to Hydrography on Georges Bank

这个项目将调查的“分布历史”的 春季和初夏，乔治河岸上的幼鳕鱼 热分层发展期。热周期 层积是一段时间，在这段时间里， 垂直和区域分布可能具有重要意义 为了生存并最终被招募该项目将利用 一种新的耳石分析技术（Sr/Ca比值）， 最近被开发出来，来追溯温度的历史， 因此，分布历史（即从 孵化捕捉），个别鳕鱼幼虫收集在各种 在乔治银行地区的水文制度。 该技术将 通过采用新技术，电子能量损失， 光谱，这将提高分辨率的Sr/Ca 技术水平能够解决亚日温度 历史 这些分析可以揭示昼夜垂直迁移 进入或穿过温跃层。 幼鳕鱼被认为与 分层沃茨的两侧乔治银行比潮汐 混合沃茨的顶部银行，并被输送到周围乔治 银行和西南部的剩余流通。 的 它们的浮游动物猎物的丰度也更丰富， 早春热锋的分层侧， 幼虫通常与最大猎物的深度有关 在温跃层的丰度。 在一年的晚些时候， 早期的幼鱼在浅滩的顶部， 密度变得大于侧面。 的确切性质 幼虫的垂直分布和面积分布 混合和分层的沃茨可能对 水平运输过程，温度对生长的影响， 浮游动物猎物的可获得性。 该项目将 采用新技术研究鳕鱼幼鱼的分布情况 并将与一项已获资助的研究建立合作联系 （NOAA），侧重于春季分层的物理学 这一过程涉及到浮游动物的完整套件， 鳕鱼和黑线鳕幼鱼的分布、生长和状况， 这是一个强大的跨学科项目

This project will investigate the "distributional histories" of larval cod on Georges Bank during the spring and early summer period of developing thermal stratification. The period of thermal stratification is a time during which the intricacies of larval cod vertical and areal distributions may hold important implications for survival and ultimately recruitment. This project will utilize a new technique of otolith analyses (Sr/Ca ratios), which has recently been developed, to hindcast the temperature histories, and hence distributional histories (that is from the time of hatching to capture), of individual cod larvae collected in various hydrographic regimes in the Georges Bank area. The technique will be advanced by employing a new technology, electron energy loss spectroscopy, which will increase the resolution of the Sr/Ca technique to a level capable of resolving sub-daily temperature histories. These analyses could reveal diel vertical migrations into or through a thermocline. Larval cod are believed to be more closely associated with the stratified waters on the sides of Georges Bank than the tidally mixed waters on top of the Bank, and are transported around Georges Bank and to the southwest with the residual circulation. The abundances of their zooplankton prey are also more abundant on the stratified side of the thermal front in early spring, and the larvae are often associated with the depth of maximum prey abundance in the thermocline. Later in the year the late larvae and early juveniles are on the top of the Bank, where zooplankton densities become greater than on the flanks. The exact nature of the vertical and areal distributions of the larvae in relation to mixed and stratified waters may be very important with regard to horizontal transport processes, temperature effects on growth, and the availability of zooplankton prey items. This project will employ new technology to examine the distributions of cod larvae and will form a collaborative link with an already-funded study (NOAA) that focuses on the physics of the vernal stratification process as it relates to the complete suite of zooplankton, and the distribution, growth and condition of cod and haddock larvae, thus making for a strong interdisciplinary program