Origins of Cod on Georges Bank: Contributions of Early Developmental Stages from the Scotian Shelf

乔治浅滩鳕鱼的起源：斯科舍大陆架早期发育阶段的贡献

• 批准号: 9813649
• 负责人: Richard Radtke
• 金额: $ 18.35万
• 依托单位: University of Hawaii
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1998
• 资助国家: 美国
• 起止时间: 1998-10-15 至 2002-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9813649&HistoricalAwards=false
• 关键词: Origins; Cod; Georges; Bank; Contributions

Origins of Cod on Georges Bank: Contribution of Early Developmental Stages from the Scotian ShelfRecent work in the Georges Bank-Gulf of Maine area has documented significant, and apparently episodic, fluxes of Scotian Shelf Water (SSW) from the Nova Scotian continental shelf to Georges Bank. SSW is a relatively cold and fresh water mass with a significant component from the St. Lawrence River, and is commonly identifiable with T-S analyses of hydrographic data and in satellite images of sea surface temperature. One such flux episode was observed March 1997 in satellite imagery and from shipboard hydrographic sampling on Georges Bank. Qualitative at-sea analyses of ichthyoplankton sampled on the March cruise revealed a remarkably tight association between abundances of gadid eggs and the distribution of SSW suggesting, along with other lines of evidence, that most of those eggs were spawned on the Scotian Shelf and were advected with the SSW water mass to Georges Bank. The fundamental question thus arises: to what extent are cod on Georges Bank imported to the Bank as early development stages by advection from Canadian waters to the east? The goal of this research is to answer this question. The approach will be two tiered: (1) performing retrospective elemental analyses of otoliths from archived larval cod samples, as well as of ichthyoplankton samples to be collected in 1998 and 1999 as part of the continuing Georges Bank GLOBEC project, analyzing them for Sr/Ca ratios, using an X-ray electron microprobe, and elemental "fingerprints", using UV lazer ablation inductively coupled plasma mass spectroscopy (ICPMS); and (2) assessing the genetic identity of the larvae relative to larval and adult populations from Georges Bank and from the Scotian Shelf using nuclear DNA microsatellite techniques.

乔治浅滩鳕鱼的起源：斯科舍陆架早期发育阶段的贡献最近在乔治浅滩-缅因湾地区的工作记录了从新斯科舍大陆架到乔治浅滩的斯科舍陆架水（SSW）的显着且明显间歇性的通量银行。 SSW 是一个相对寒冷的淡水团，主要成分来自圣劳伦斯河，通常可以通过水文数据的 T-S 分析和海面温度的卫星图像来识别。 1997 年 3 月，卫星图像和乔治浅滩船上水文采样观测到了一次这样的通量事件。 对三月航行中采集的浮游鱼类样本进行的海上定性分析显示，海鱼卵的丰度与SSW的分布之间存在着非常紧密的联系，与其他证据一起表明，这些卵中的大多数是在斯科舍大陆架上产卵并通过平流输送的与 SSW 水团一起到达乔治浅滩。 因此出现了一个基本问题：乔治浅滩上的鳕鱼在早期发育阶段在多大程度上是通过从加拿大水域向东部的平流进口到乔治浅滩的？ 本研究的目的就是回答这个问题。 该方法将分为两个层次：(1) 对存档的鳕鱼幼虫样本以及 1998 年和 1999 年作为持续的乔治银行 GLOBEC 项目的一部分收集的鱼类浮游生物样本的耳石进行回顾性元素分析，分析它们的 Sr/ Ca 比率（使用 X 射线电子显微探针）和元素“指纹”（使用 UV 激光烧蚀感应耦合等离子体）质谱（ICPMS）； (2) 使用核 DNA 微卫星技术评估幼虫相对于乔治滩和斯科舍大陆架的幼虫和成虫种群的遗传特性。