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首页> 外文学位 >Factors affecting overwinter mortality and early marine growth in the first ocean year of juvenile Chinook salmon in Quatsino Sound, British Columbia.
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Factors affecting overwinter mortality and early marine growth in the first ocean year of juvenile Chinook salmon in Quatsino Sound, British Columbia.

机译：在不列颠哥伦比亚省Qussino Sound的第一个大洋基努克鲑鱼越冬死亡率和早期海洋生长的因素。

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摘要

Evidence suggests that the variability in recruitment of adult Pacific salmon is related to smolt survival during the first ocean year. Specifically, the first few weeks and first marine winter may be two critical periods of high mortality during early marine life. Mortality during early marine residency has been attributed to predation and size-dependent factors while high mortality during the first winter may be due to energy deficits and failure to reach a certain size by the end of the growing season. My study assessed factors influencing overwinter mortality and early marine growth in juvenile Chinook salmon (Oncorhynchus tshawytscha) from Marble River, Quatsino Sound, British Columbia. Juvenile salmon were collected during November 2005 and 2006 (fall) and March 2006 and 2007(winter). Mortality rates over the first winter derived from catch per unit effort across seasons ranged between 80-90% in all years. These are the first estimations of overwinter mortality in juvenile Pacific salmon. Fish size distributions showed no evidence of size-selective overwinter mortality between fall and winter fish in either 2005-2006 or 2006-2007. Otolith microstructure analyses showed no significant difference in circulus increment widths during the first four weeks after marine entry. Similarities in increment width indicated that early marine growth did not differ between fall and winter fish during early marine residency in 2006. These observations show that the high overwinter mortality rates of juvenile Chinook salmon in Quatsino Sound are not size-dependent. Total plankton biomass was significantly lower in the winter season but size distribution, gut fullness and energy density data did not show evidence of starvation. No correlation was found between early marine growth, size, energy accumulation and high mortality in Marble River juvenile Chinook salmon during their first ocean winter in Quatsino Sound. Possible factors influencing these high mortality rates may include non size-selective predation, disease, local environmental influences or an as yet unknown source. Future work should continue to focus on understanding the relationship between early marine survival and adult recruitment. The expansion of growth comparisons geographically and chronologically while determining the effects of predatory mortality on juvenile Chinook salmon along the north Pacific continental shelf and beyond are imperative to fully understanding this complex marine life stage.
机译：有证据表明，成年太平洋鲑鱼的募集量变化与第一个海洋年的软体动物生存有关。具体而言，前几个星期和第一个海洋冬季可能是海洋早期生命中两个高死亡率的关键时期。早期海洋居留期间的死亡率归因于掠食和与大小有关的因素，而第一个冬季的高死亡率可能是由于能量不足和在生长季节结束时未能达到一定的大小所致。我的研究评估了影响不列颠哥伦比亚省Quatsino Sound大理石河中的奇努克鲑鱼（Oncorhynchus tshawytscha）的越冬死亡率和早期海洋生长的因素。在2005年11月和2006年（秋季）以及2006年3月和2007年（冬季）收集了幼鲑。每年第一个冬季的死亡率均源于整个季节单位捕捞量的80-90％。这些是太平洋鲑幼鱼越冬死亡率的首次估计。鱼的大小分布没有证据表明在2005-2006年或2006-2007年秋季和冬季鱼之间有选择大小的越冬死亡率。耳石的微结构分析显示，在海洋进入后的前四周内，环行增量宽度没有显着差异。增量宽度的相似性表明，在2006年早期海洋居留期间，秋季鱼和冬季鱼之间的早期海洋生长没有差异。这些观察结果表明，在Quatsino Sound的奇努克鲑幼鱼的高越冬死亡率与大小无关。在冬季，浮游生物的总生物量显着降低，但大小分布，肠道饱满度和能量密度数据并未显示出饥饿的迹象。在Quatsino Sound的第一个海洋冬季，大理石河中的奇努克鲑鱼的早期海洋生长，大小，能量积累和高死亡率之间没有相关性。影响这些高死亡率的可能因素可能包括非大小选择性的捕食，疾病，局部环境影响或来源尚不清楚。未来的工作应继续集中于了解早期海洋生存与成年征募之间的关系。在确定掠夺性死亡率对北太平洋大陆架及其他地区的奇努克鲑鱼的影响时，按地理和时间顺序进行的增长比较的扩展对于充分了解这一复杂的海洋生物阶段至关重要。

著录项

  • 作者

    Middleton, Katherine Rose.;

  • 作者单位

    University of Victoria (Canada).;

  • 授予单位 University of Victoria (Canada).;
  • 学科 Biological oceanography.
  • 学位 M.Sc.
  • 年度 2011
  • 页码 112 p.
  • 总页数 112
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

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