• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文会议>International Symposium on the Management and Biology of Dogfish Sharks >Trends in Abundance of Spiny Dogfish in the Strait of Georgia, 1980-2005
【24h】

Trends in Abundance of Spiny Dogfish in the Strait of Georgia, 1980-2005

机译：1980 - 2005年格鲁吉亚海峡丰富刺鲨鱼丰富趋势

获取原文
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

Spiny dogfish Squalus acanthias have been an important component of the Strait of Georgia fisheries from the late 1800s to the late 1940s, when the fishery collapsed owing to overfishing and changes in market demand. The stock population levels have sustained a commercial fishery of approximately 2,000 metric tons since 1978. Recent concerns regarding the status of dogfish stocks worldwide have reprioritized the status assessment of dogfish in British Columbia. Longline research surveys were conducted for dogfish in the Strait of Georgia in 1986, 1989, and 2005. Additional sources of information are catch and effort data collected through logbook records from the commercial longline fishery. Recent improvements in gear configuration resulted in a switch in the mid-1990s from traditional J hooks to circle hooks, which makes direct comparison of catch rates difficult. In November 2004 a calibration experiment using J hooks and circle hooks demonstrated that, overall, spiny dogfish catch per unit effort (CPUE) for circle-hook gear was 1.6-1.7 times higher than that for J-hook gear. After applying this conversion to the commercial longline CPUE data available for 1980-1984 and 2000-2004, no significant trend in catch rate over time was detected. The catch rate observed in the longline research survey actually increased in 2005 compared to 1986 and 1989. In both fisheries and research data, the proportion of smaller spiny dogfish in the size distribution has increased, reducing the overall mean size.The decline in mean size is probably due to an increase in recruitment of juvenile fish. However, caution in management of this stock is warranted given that the current commercial fishery is now landing a large proportion (estimated 80%) of immature fish. Increased fishing pressure on juveniles could have implications for the abundance of mature fish in upcoming decades.
机译：白斑角鲨角鲨鲨已经海峡从19世纪后期格鲁吉亚渔业对20世纪40年代后期的一个重要组成部分，当渔业崩溃，由于过度捕捞和市场需求的变化。自1978年以来关于角鲨种群状况的担忧近期全球有reprioritized角鲨的不列颠哥伦比亚省的地位评估股票人口水平已经持续约2000公吨商业性渔业。延绳钓研究调查是为角鲨海峡格鲁吉亚于1986年，1989年进行的，和2005年的其他信息源是通过日志记录从商业延绳钓渔业收集渔获量和努力的数据。在齿轮构造最新的改进导致了90年代中期，以圆钩一个开关从传统的J挂钩，这使得捕获率的直接比较困难。在2004年11月使用J挂钩和圈挂钩表明，总体而言，对于每圈钩齿轮单元工作（CPUE）角鲨捕获比为J形钩齿轮更高1.6-1.7倍的校准实验。应用这种转换可用于1980 - 1984年和2000 - 2004年商业延绳钓CPUE数据后，检测捕获率不会随时间显著趋势。在2005年实际增长相比，1986年和1989年在渔业和研究数据的延绳钓研究调查观察到的捕获率，在大小分布更小白斑角鲨的比例有所上升，降低平均大小的总体平均下降size.The可能是由于增加幼鱼的招聘。然而，在这个股票的管理谨慎是必要考虑到当前商业性渔业现已登陆不成熟的鱼大的比例（约80％）。对青少年增加捕捞压力可能对即将举行的几十年丰富的成熟鱼的影响。

著录项

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