• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文会议>American Fisheries Society/Sea Grant Symposium "Mitigating impacts of natural hazards on fishery ecosystems" >Natural Hazards, Stock Depletion, and Stock Managemei in the Southern Gulf of Mexico Pink Shrimp Fishery
【24h】

Natural Hazards, Stock Depletion, and Stock Managemei in the Southern Gulf of Mexico Pink Shrimp Fishery

机译：在墨西哥南湾桃红虾渔业的自然灾害，股票消耗和股票管理

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

摘要

The southern Gulf of Mexico has historically sustained important fisheries, particularly shrimp. From the mid-1950s to early 1970s, annual yields of shrimp averaged about 27,000 metric tons (mt), of which the pink shrimp Farfantepenaeus du-orarum contributed more than 80%. At that time, three fleets, from the United States, Cuba, and Mexico, exploited the stock. Pink shrimp captures have declined from the mid-1970s to the present level of about 1,000 mt per year, indicating severe stock depletion. Amonotonically decreasing recruitment rate, beginning in the early 1970s, was identified through reconstruction of the stock, based on age-structured analysis. At the beginning of the 1980s, total fishing effort decreased more than 40% because U.S. and Cuban fleets retired from this fishing ground, and about 50% of the Mexican fleet stopped operations because boat ownership was transferred from the private sector to fishing cooperatives. During this time, recruitment continued decreasing but at a slowerrate. Because of the high yields obtained during the 1950s and 1960s, depletion was interpreted as caused by overfishing, especially since juveniles had been intensively exploited in coastal areas. Another hypothesis to explain the drop in recruitment was the start of oil industry operations in the 1980s; this theory was subsequently discarded because the recruitment rate reduction started in the early 1970s. In addition to the Ixtoc I oil spill in 1979, several natural events during the 1980s and 1990scoincided with the decrease in recruitment rate, including three high-impact hurricanes. Also, during this time, ash ejected by the Chichonal volcano covered large expanses of coastal sea grasses, which serve as shrimp nursery areas. Using trends in recruitment rate anomalies, we identified recruitment failures caused by these natural hazards, but the time series showed that once the effect was removed, the pink shrimp stock responded towards recovery, so these events alone do not explain the stock depletion. Recruitment anomalies were strongly associated with changes in regional primary production, and both series showed a negative shift in the mid-1980s. We concluded that there are two time frames--short-term impacts caused by hurricanes, the volcanic eruption, and even oil spills; and a long-term effect associated with decreasing primary production. We found that this long-term effect is heavily influenced by related environmental changes, such as increases in water level and temperature, a decrease in salinity, the low intensity of turbulence in this area, the absence of river discharges that promote primary production, and the low-energy hydrodynamics of the southern Gulf of Mexico. We suggest that the decrease in recruitment rate was stronglyinfluenced by a decrease in salinity and the decrease in primary productivity, which is the main source of food for the shrimp. This discovery changed the objectives of management policy. Previously, the main objective was stock recovery, but now management policy is aimed at stock maintenance, especially of reproductive females, while waiting for a favorable change in productivity levels.
机译：墨西哥湾南部历史上持续了重要的渔业，特别是虾。从20世纪50年代中期到20世纪70年代初，年产量的虾率平均约为27,000公吨（MT），其中粉红色的虾Farfantepenaeus du-Orarum贡献了超过80％。那时，来自美国，古巴和墨西哥的三个舰队，利用了股票。粉红色的虾捕获从20世纪70年代中期下降到每年约1,000吨的目前水平，表明严重库存枯竭。从20世纪70年代初开始，在20世纪70年代初开始，通过重建的年龄结构分析来确定招聘率。在20世纪80年代初，渔业努力的总捕捞量降低了40％以上，因为美国和古巴舰队从这个渔场退役，约有50％的墨西哥舰队停止运营，因为船只所有权从私营部门转移到渔业合作社。在此期间，招聘持续减少，但在较慢的情况下继续下降。由于在20世纪50年代和20世纪60年代获得的高收益率，耗尽被解释为通过过度捕捞引起的，特别是因为少年在沿海地区密切地剥削了。另一个解释招聘下降的假设是20世纪80年代石油工业业务的开始;随后丢弃了该理论，因为在20世纪70年代初开始招聘率减少。除了1979年IXTOC I漏水之外，20世纪80年代和1990年期间的几次自然事件，减少了招聘率，包括三次高飓风。此次，在此期间，被奇数火山喷射的灰烬覆盖了大型沿海草草，该草被担任虾苗地区。利用招聘率异常的趋势，我们确定了由这些自然灾害引起的招聘失败，但时间序列显示，一旦效果被移除，粉红色的虾库存就会回复，因此这些事件不解释库存枯竭。招聘异常与区域初级生产的变化密切相关，两系都在20世纪80年代中期表现出负面的转变。我们得出结论，有两种时间框架 - 飓风造成的短期影响，火山喷发，甚至溢油造成的影响;与降低初级生产相关的长期效果。我们发现这种长期效果受相关环境变化的严重影响，例如水位和温度的增加，盐度降低，该区域的湍流强度，缺乏促进初级生产的河流排放，墨西哥南湾的低能量流体动力学。我们建议招聘率的减少强烈因盐度降低和初级生产率降低，这是虾的主要食物来源。这一发现改变了管理政策的目标。此前，主要目标是股票恢复，但现在管理政策旨在瞄准股票维护，特别是对生殖女性的股票维护，同时等待有利的生产率水平变化。

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