Fishing effects on age and spatial structures undermine population stability of fishes
Fishing effects on age and spatial structures undermine population stability of fishes
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DOI：
10.1007/s00027-009-0122-2
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发表时间：
2010-03-01
期刊：
影响因子：
2.4
通讯作者：
Wang, Wei-Fen
中科院分区：
文献类型：
--
作者：
Hsieh, Chih-hao;Yamauchi, Atsushi;Wang, Wei-Fen
过度捕捞造成了被捕捞种群结构和生态系统的巨大变化。本文主要研究了捕捞对被捕捞鱼类的年龄（大小）和空间结构的影响。越来越多的证据表明，大而有经验的产卵个体能够产生更高质量和数量的卵，即所谓的母体效应，不同年龄段的个体倾向于在不同的地点和时间产卵。这些行为与健康的年龄结构有关，有助于提高下注对冲能力，这对于消除短期环境变化非常重要。在这里，我们记录了一个普遍的现象，即被捕捞种群的年龄（大小）被截断，这是由规模选择性渔业清除所驱动的。这种大小选择性捕捞可能会产生进化后果，而且可能很难逆转。此外，捕鱼往往会减少种群的空间异质性，这也对下注对冲起到重要作用。研究表明，年龄截断和空间异质性的降低降低了被剥削群体面对变化环境的复原力，并提高了波动幅度。最近的分析表明，鱼类种群往往表现出非线性性质，并有可能在短时间内发生急剧变化。所有证据都表明，通过改变年龄或空间结构，捕鱼可能会使被捕捞的鱼类更容易发生灾难性的变化。因此，为了实现渔业的可持续发展，除了可存活的产卵生物量外，管理还应保护鱼龄和空间结构。
Overfishing has caused dramatic changes in structures of exploited populations as well as ecosystems. In this article, we focus on fishing effects on age (size) and spatial structures of exploited fishes. Accumulating evidence has shown that large and experienced spawning individuals are able to produce higher quality and quantity of eggs, known as maternal effects, and that individuals of different age classes tend to spawn in different locations and times. These behaviors are associated with a healthy age structure and contribute to bet-hedging capacity that is important in smoothing out short-term environmental variability. Here, we document a widespread phenomenon of age (size)-truncation of exploited populations driven by size-selective fishery removals. Such size-selective fishing may have evolutionary consequence and may be difficult to reverse. In addition, fishing often reduces population spatial heterogeneity that also contributes importantly to bet-hedging. We review studies showing that the effects of age truncation and reduction of spatial heterogeneity have reduced resilience and elevated the fluctuation amplitude of exploited populations facing a changing environment. Recent analyses indicated that fish populations often exhibit nonlinear nature and have potential to shift dramatically in a short time. All the evidence suggests that fishing, by altering age or spatial structures, may make exploited fishes, more prone to catastrophic shifts. Therefore, to achieve sustainable fisheries, management should conserve the age and spatial structure in addition to viable spawning biomass.