U.S.-GLOBEC: NEP Phase IIIb-CGOA: Habitat effects on feeding, condition, growth and survival of juvenile pink salmon in the northern Gulf of Alaska

东北太平洋是越来越多的海洋学的兴趣，鲑鱼丰度的十年尺度波动的观测似乎与全流域的气象强迫和海洋条件的变化。这些制度的转变表明，气候变化迅速表现在生物生产力，虽然机制，改变生态系统的结构和功能没有得到很好的记录。粉红鲑鱼特别适合作为海洋条件的指标，因为它们数量丰富，生命周期短，两年，世代不重叠。幼年粉红鲑鱼从威廉王子湾（PWS）孵化场进行热耳石标记，允许估计在其早期海洋阶段的增长和整体队列生存，从而提供了一个特殊的机会，研究栖息地质量的影响。因此，该项目使用的数据从四个方案，采样青少年粉红鲑鱼在北方果阿估计喂养强度，条件和增长，每个孵化队列的时间和栖息地。有利生境的出现由于幼鲑的死亡率在较大个体中降低，因此在基于较大个体的上部分位数中确定摄食、状况和生长作为较大个体的特征，生长较快的个体可能比总体平均值或中位数更能反映生境质量。这种综合策略是一种自上而下的方法，因为是鱼类决定何时何地出现有利的栖息地。对气候和海洋条件影响海洋生态系统和鲑鱼生产的过程仍然缺乏机械的了解。最佳稳定性假说（奥什）表明，在北方果阿，在夏季增加水柱稳定性提高初级生产和浮游动物丰度，从而提高幼鲑鱼的摄食，生长和生存。对水柱稳定性、叶绿素的深度分布、深度的光可用性、浮游动物丰度和鲑鱼反应变量（摄食、条件和生长）进行了检查，以确定它们之间的重要相互关系及其对奥什的影响。博士学位学生和博士后研究员支持这项工作。科学家在阿拉斯加部。渔业和野味局正在为该数据库提供一套数据，该数据库将受益于早期海洋生存的估计，以改善预测。 该项目与PWS鲑鱼渔业的利益相关者联盟保持着强有力的互动。该小组开发的一个网站用于向PWS和北方果阿更广泛的资源依赖社区传达我们的综合研究结果。

The northeast Pacific Ocean is of increasing oceanographic interest as observations of decadal-scale fluctuations in salmon abundance appear linked to basin-wide changes in meteorological forcing and oceanographic conditions. These regime shifts indicate that climate changes are quickly expressed in biological productivity, although the mechanisms that alter ecosystem structure and function are not well documented. Pink salmon are particularly suited to serve as indicators of marine conditions, as they are abundant and have a short, two-year life cycle with non-overlapping generations. Juvenile pink salmon from Prince William Sound (PWS) hatcheries carry thermal otolith marks that allow estimates of both growth in their early marine phase and of overall cohort survival, thus providing an exceptional opportunity to study the effects of habitat quality. Thus project uses data from four programs that sampled juvenile pink salmon in the northern GOA to estimate feeding intensity, condition, and growth for each hatchery cohort by time and habitat. The occurrence of favorable habitats (i.e. where juvenile pink salmon were feeding well, were in good condition, and exhibited fastest growth) will be identified, allowing description of their characteristics.Since mortality of juvenile salmon is reduced in larger individuals, feeding, condition and growth is determined in upper size-based quantiles as characteristics of larger, faster-growing individuals may present better indicators of habitat quality than overall means or medians. This synthesis strategy is a top-down approach, as it is the fish that decide where and when favorable habitats occurred. Mechanistic understanding of the processes by which climate and oceanographic conditions affect marine ecosystems and salmon production is still lacking. The OptimalStability Hypothesis (OSH) suggests that, in the northern GOA, increased water column stability during summer enhances primary production and zooplankton abundance; leading to enhanced feeding, growth and survival of juvenile salmon. Water column stability, depth distribution of chlorophyll, light availability at depth, zooplankton abundance and salmon response variables (feeding, condition and growth) are examined to determine significant inter-relationships among them, and their bearing on the OSH.This project will lead to the development of a comprehensive database for pink salmon juveniles, compiled from four projects. A Ph.D. student and a post-doctoral fellow are supported by this work. Scientists at the Alaska Dept. of Fish and Game are providing a data set for the database will benefit from estimates of early marine survival to improve forecasting. The project maintains a strong interaction with an alliance of stakeholders in the PWS salmon fishery. A website developed by that group is used to communicate results of our synthesis research to the broader resource-dependent community of PWS and the northern GOA.