• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文学位 >Potential impacts of a fishway and predatory fishes on juvenile river herring recruitment in an upstream impoundment.
【24h】

Potential impacts of a fishway and predatory fishes on juvenile river herring recruitment in an upstream impoundment.

机译：一条鱼道和掠夺性鱼类对上游水库中幼鱼鲱鱼招募的潜在影响。

获取原文
获取原文并翻译 | 示例
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

Migratory stocks of river herring (alewife Alosa pseudoharengus, blueback herring A. aestivalis) have declined significantly due to overfishing, poor water quality, and loss of spawning and nursery habitat. Fish passage facilities are being installed at stream blockages to recover lost habitat. A fish ladder was installed in 1997 on Unicorn Lake, a tributary to the Chester River in Maryland. I evaluated the effectiveness of the fish ladder for passing adult river herring, and measured the potential effects of resident predatory fish on river herring recruitment in 1998 and 1999. In 1998, 18 alewife and 3,800 blueback herring used the fishway, but temporary modifications to the fishway in 1999 significantly increased passage to 1,200 alewife (3,400 additional alewife manually passed) and 13,400 blueback herring. Although juvenile river herring reportedly stay in upstream areas for several months, none were collected while sampling in subsequent summers in Unicorn Lake. Reasons for the apparent recruitment failure may have been attributed to low food availability, poor water quality, early migration, or predation on early life stages. I collected stomach contents from predatory fish in Unicorn Lake and in Unicorn Branch below the fishway where juvenile river herring were present. No juvenile river herring were collected in the stomach contents of these species, although river herring were collected in the vicinity of predatory fish in Unicorn Branch. I speculate that if juvenile river herring production were successful in Unicorn Lake, predation on juveniles by resident fishes would be negligible.
机译：由于过度捕捞，水质差以及产卵和苗圃栖息地的丧失，河鲱（（鱼Alosa pseudoharengus，蓝鲱A. aestivalis）的迁徙种群已大大减少。鱼流设施正在溪流阻塞处安装，以恢复失去的栖息地。 1997年，在马里兰州切斯特河的支流独角兽湖上安装了鱼梯。我评估了鱼梯通过成年河鲱鱼的有效性，并测量了1998年和1999年常驻掠食性鱼类对河鲱鱼招募的潜在影响。1998年，有18条阿勒威夫鱼和3,800条蓝鲱鱼使用了鱼道，但对鱼道进行了临时修改。 1999年的鱼道显着增加了通行证，使通行证增加到1,200个（其中3,400个手动通过了），以及13,400个蓝鲱鱼。尽管据报告幼鱼鲱鱼在上游地区停留了几个月，但随后的夏天在独角兽湖采样时却没有采集到。明显的招募失败的原因可能是由于粮食供应​​不足，水质差，早期迁徙或生命早期被捕食。我从存在幼鱼鲱鱼的独角兽湖和独角兽分支下面的掠食性鱼类中收集了胃中的内容。尽管在独角兽分公司的掠食性鱼类附近收集了河鲱，但在这些物种的胃中未发现幼鱼。我推测，如果独角兽湖中的幼鱼鲱鱼生产成功，居民鱼类对幼鱼的捕食将是微不足道的。

著录项

  • 作者

    Eyler, Sheila M.;

  • 作者单位

    University of Maryland Eastern Shore.;

  • 授予单位 University of Maryland Eastern Shore.;
  • 学科 Biology Ecology.;Agriculture Fisheries and Aquaculture.
  • 学位 M.S.
  • 年度 2000
  • 页码 85 p.
  • 总页数 85
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号