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首页> 外文学位 >Lentic habitat use of roundtail chub Gila robusta and overlap with two nonnative piscivores, brown trout Salmo trutta and lake trout Salvelinus namaycush.
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Lentic habitat use of roundtail chub Gila robusta and overlap with two nonnative piscivores, brown trout Salmo trutta and lake trout Salvelinus namaycush.

机译：使用圆尾chu吉拉罗布斯塔（Gila Robusta）的扁豆栖息地，并与两个非本地食肉动物（褐鳟Salmo trutta和湖鳟Salvelinus namaycush）重叠。

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摘要

Roundtail chub Gila robusta were historically widespread in the Colorado River drainage, but are now found in only 45% of their historic range and in low abundances. Range-wide declines in roundtail chub abundance are due to anthropogenic impacts from dams and water diversions and to additions of nonnative fishes to the system. This Colorado River endemic is commonly known as a "Big River" fish occurring in lotic environments, but isolated populations of roundtail chub are found in six natural lakes in the upper basin. These lakes contain the only lentic populations of roundtail chub, and little is known about their life history in these systems. The purpose of this study was to determine habitat use of roundtail chub in lentic systems and to explore potential impacts from two introduced species of predators, brown trout Salmo trutta and lake trout Salvelinus namaycush in two of the lakes where roundtail chub occur. Roundtail chub were commonly sampled in littoral habitats, occurred seldom in pelagic habitats, and were absent from deep benthic habitats. Brown trout tended to overlap with roundtail chub in the littoral zone both before and after thermal stratification, while lake trout tended to overlap with roundtail chub only before stratification. Brown trout consumed higher proportions of minnows than lake trout, especially after thermal stratification. Stable isotopic signatures (delta13C and delta15N) of brown trout and lake trout revealed that brown trout assimilated a greater proportion of their diet from fish that did lake trout, but instances of roundtail chub consumption by these predators were rare among fish sampled.
机译：圆尾吉拉robust在历史上在科罗拉多河流域很普遍，但是现在仅在其历史范围的45％处发现并且丰度很低。范围广泛的round尾decline丰度下降是由于水坝和调水对人为的影响以及向系统中添加非本地鱼类的结果。这种科罗拉多河地方病通常被称为“大河”鱼，发生在抽水环境中，但是在上流域的六个天然湖泊中发现了孤立的圆尾种群。这些湖泊仅是长尾round的片状透镜种群，对其在这些系统中的生活史知之甚少。这项研究的目的是确定在透镜系统中使用圆尾的栖息地，并探讨引入的两种捕食物种潜在的影响，在两个圆尾发生的两个湖泊中，褐鳟鳟鱼和鳟鳟鱼都存在。圆尾通常在沿海生境中采样，在浮游生境中很少发生，深海底栖生境中则不存在。在热分层之前和之后，褐鳟倾向于在沿海区与圆尾tail重叠，而湖鳟倾向于在分层之前与圆尾重叠。褐鳟消耗的lake鱼比例高于湖鳟，特别是在热分层之后。褐鳟和湖鳟的稳定同位素特征（δ13C和δ15N）表明，褐鳟从做鳟鱼的鱼中吸收了更大比例的饮食，但是在这些被捕食的鱼类中，捕食round尾round的情况很少。

著录项

  • 作者

    Laske, Sarah M.;

  • 作者单位

    University of Wyoming.;

  • 授予单位 University of Wyoming.;
  • 学科 Biology Zoology.;Agriculture Fisheries and Aquaculture.
  • 学位 M.S.
  • 年度 2010
  • 页码 155 p.
  • 总页数 155
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

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