为什么捕鱼会放大鱼类丰富度的波动?
Christian N K Anderson1, Chih-hao Hsieh, Stuart A Sandin
1Scripps Institution of Oceanography, University of California, San Diego, La Jolla, California 92093, USA.
Nature
|April 19, 2008
概括
捕鱼可以使鱼群变得更加不稳定. 这项研究揭示了利用鱼类种群的年龄削减,而不是渔业压力或环境跟踪,从根本上推动了人口不稳定性和渔业的繁荣-衰退周期.
科学领域:
- 海洋生物学 海洋生物学
- 渔业 科学 渔业 科学
- 人口动态 人口动态
背景情况:
- 捕捞种群的波动比未捕捞种群的波动更大,但根本原因尚不清楚.
- 三种假设解释了这种变异性:捕捞压力的直接影响,平均体型/年龄的减少以及年龄截减种群的变化种群动态.
研究的目的:
- 调查导致捕捞种群时间变化增加的机制.
- 通过使用长期渔业数据,区分直接渔业影响,环境跟踪和变化的种群动态.
主要方法:
- 分析了加利福尼亚合作海洋渔业调查 (CalCOFI) 50年来的鱼记录.
- 关于利用鱼类种群的种群变异性的三个竞争假设的评估.
主要成果:
- 没有证据支持可变的捕捞压力直接增加了种群的变化.
- 有限的证据表明,商业渔业减少了平均体型和年龄,导致了直接的环境跟踪.
- 强有力的证据表明,因人口参数的变化,年龄截止人口表现出不稳定的动态.
结论:
- 加州的时间变化增加当前的渔业源于人口动态的固有不稳定性,而不是直接的开发或环境跟踪.
- 选择性采摘改变了基本的人口动态,导致繁荣衰退周期和潜在的库存下降.
- 这些发现对可持续的渔业资源管理有重大影响.
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