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

小行星9319843汤森 本计画将调查乔治河岸在春季与初夏温度层化发展期间，幼鳕的“分布历史”。 热分层的时期是一个时间，在此期间，幼虫鳕鱼的垂直和区域分布的复杂性可能会对生存和最终招聘的重要影响。 该项目将利用一种新的耳石分析技术（Sr/Ca比值），这是最近开发的，追溯温度的历史，因此分布的历史（即从孵化到捕获的时间），收集在乔治银行地区的各种水文制度的个别鳕鱼幼虫。 该技术将通过采用一种新技术，电子能量损失光谱学，这将提高分辨率的Sr/Ca技术的水平，能够解决亚每日温度的历史。 这些分析可以揭示昼夜垂直迁移进入或通过温跃层。 鳕鱼幼鱼被认为是更密切相关的分层沃茨的两侧乔治银行比潮汐混合沃茨的顶部的银行，并被运送到周围乔治银行和西南部的剩余流通。 其浮游动物猎物的丰度也更丰富的分层侧的热锋在早春，和幼虫往往与最大猎物丰度的温跃层的深度。 在今年晚些时候，晚期的幼虫和早期的少年在银行的顶部，那里的浮游动物密度变得比侧翼更大。 幼虫的垂直和区域分布的混合和分层的沃茨的确切性质可能是非常重要的水平运输过程，温度对生长的影响，以及浮游动物的猎物项目的可用性。 该项目将采用新技术来研究鳕鱼幼虫的分布，并将与已经资助的研究（NOAA）形成合作联系，该研究重点是春季分层过程的物理学，因为它涉及到全套浮游动物，以及鳕鱼和黑线鳕幼虫的分布，生长和条件，从而形成一个强大的跨学科计划。 ***

9319843 Townsend 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 a nd 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. ***