Salmon otoliths - hatchery thermal marks from F/V Great Pacific, R/V Miller Freeman multiple cruises in the Coastal Gulf of Alaska, NE Pacific from 2001-2004 (NEP project)

<p><strong>GLOBEC 2000: Factors Affecting the Distribution of Juvenile Salmon in the Gulf of Alaska</strong><br />
<em>J. Helle (NMFS/AFSC, Auke Bay Laboratory)</em><br />
<em>E. D. Cokelet (Pacific Marine Environmentla Laboratory),<br />
E. V. Farley, Jr. (NMFS/AFSC, Auke Bay Laboratory),<br />
A. B. Hollowed (NMFS/AFSC),<br />
P. J. Stabeno (Pacific Marine Environmental Laboratory)</em></p>

<p>\"Remarkable changes in atmospheric, oceanic and biological conditions have occurred in recent decades in the North Pacific Ocean including declines in the marine survival of some salmon stocks. Fishery scientists generally agree that in the first few months after leaving freshwater, salmon survival and growth are linked to oceanic variability. The purpose of this research is to focus National Marine Fisheries Service studies on the GLOBEC region, augment oceanographic measurements and determine what biological and physical factors influence the distribution of juvenile salmon. Three general hypotheses are explored in this proposal: (1) juvenile salmon prefer the buoyancy-driven Alaska Coastal Current (ACC) at the head of the Gulf of Alaska, (2) they associate with oceanic temperature, salinity, current and prey fields, and (3) they migrate landward of Kodiak Island in the ACC rather than seaward in the Alaskan Stream. Annual, summer cruises aboard a chartered fishing vessel will catch juvenile salmon on 10 transects between Yakutat Bay and Kodiak Island. The vessel will be outfitted with a thermosalinograph to measure sea-surface temperature and salinity, and with an Acoustic Doppler Current Profiler (ADCP) - each operating continuously for fine-scale resolution. Modeled tidal currents will be removed from ADCP measurements to reveal the mean flow fields. At each trawl site, temperature and salinity profiles will provide water-column properties, and bongo-net hauls will give zooplankton distributions. Stomach samples from juvenile salmonids will be analyzed in the laboratory for diet composition and compared with zooplankton distributions. Analysis of salmon otoliths for hatchery thermal marks and Genetic Stock Identification techniques will be used to determine the home stream of hatchery and wild stocks in the Gulf of Alaska and their distribution with respect to oceanographic regimes. Retrospective analysis of catch per unit effort versus oceanographic and prey factors will reveal what affects the distribution of pink, chum, coho and sockeye salmon in the study region. Proxies for bio-physical factors will be developed and compared with salmon-run size.\"<em>(project proposal)</em></p>

<p><strong>Data Collection Details</strong><br />
Types: CTD profiles, ADCP profiles of ocean current, juvenile salmonid catch statistics from trawls, salmonid stomach samples analyzed for diet composition, salmonid otolith analyses, Genetic Stock Identification, zooplankton distributions from bongo-net hauls.<br />
Platform: Chartered fishing vessel<br />
Spatial extent: 10 transects perpendicular to the coast between Yakutat Bay and Kodiak Island<br />
Temporal extent: ~2 weeks each July-August of 2001-2004.</p>

# GLOBEC 2000：阿拉斯加湾幼鲑分布的影响因子
*J. Helle（美国国家海洋渔业局/阿拉斯加渔业科学中心，奥克湾实验室）*
*E. D. Cokelet（太平洋海洋环境实验室），E. V. Farley Jr.（美国国家海洋渔业局/阿拉斯加渔业科学中心，奥克湾实验室），A. B. Hollowed（美国国家海洋渔业局/阿拉斯加渔业科学中心），P. J. Stabeno（太平洋海洋环境实验室）*

“近几十年来，北太平洋大气、海洋与生物环境发生了显著变化，部分鲑鱼种群的海洋存活率出现下降。渔业科学家普遍认为，鲑鱼脱离淡水后的最初数月内，其存活与生长状况与海洋环境变率紧密相关。本研究旨在将美国国家海洋渔业局的研究聚焦于全球海洋生态系统动力学（Global Ocean Ecosystem Dynamics, GLOBEC）研究区域，扩充海洋观测项目，并明确影响幼鲑分布的生物与物理因子。本提案共探讨三项核心假设：（1）幼鲑偏好阿拉斯加湾头部由浮力驱动的阿拉斯加沿岸流（Alaska Coastal Current, ACC）；（2）幼鲑的分布与海洋温度、盐度、海流及饵料场密切相关；（3）幼鲑会沿阿拉斯加沿岸流向科迪亚克岛近岸洄游，而非沿阿拉斯加海流向外海移动。

本研究将每年夏季租用渔船，在雅库塔特湾与科迪亚克岛之间的10条断面开展采样作业，采集幼鲑样本。船只将配备温盐仪以连续采集表层海水温度与盐度数据，并配备声学多普勒流速剖面仪（Acoustic Doppler Current Profiler, ADCP）以实现精细尺度的流速观测。研究将从ADCP观测数据中移除模拟得到的潮流数据，以提取平均流场信息。在每个拖网采样点，将通过温盐剖面获取水团属性，并通过邦戈网拖网采集浮游动物样本以获取其分布情况。实验室将分析幼鲑的胃容物样本，明确其饮食组成，并将其与浮游动物分布进行比对。通过分析鲑鱼耳石的孵化场热标记，并采用遗传种群识别（Genetic Stock Identification, GSI）技术，本研究将确定阿拉斯加湾内孵化场种群与野生种群的产卵溪流来源，并明确其与海洋环境格局的分布关联。通过单位捕捞努力量渔获量与海洋环境及饵料因子的回顾性分析，将明确研究区域内粉鲑（Pink Salmon）、大麻哈鱼（Chum Salmon）、银鲑（Coho Salmon）与红鲑（Sockeye Salmon）的分布影响因子。此外，本研究将构建生物-物理因子的替代指标，并与鲑鱼洄游种群规模进行比对分析。”（项目提案）

## 数据采集详情
数据类型：温盐深（CTD）剖面数据、海流声学多普勒流速剖面仪（ADCP）剖面数据、拖网采集的幼鲑捕捞统计数据、用于饮食组成分析的鲑科鱼类胃容物样本、鲑科鱼类耳石分析数据、遗传种群识别（GSI）数据、邦戈网拖网获取的浮游动物分布数据。
观测平台：租用渔船
空间范围：雅库塔特湾至科迪亚克岛之间垂直于海岸的10条断面
时间范围：2001-2004年每年7-8月，单次观测时长约2周。