National Institute of Aquatic Resources, Technical University of Denmark, , 2920 Charlottenlund Slot, Charlottenlund, Denmark.
Proc Biol Sci. 2010 Mar 7;277(1682):795-802. doi: 10.1098/rspb.2009.1512. Epub 2009 Nov 11.
The largest perturbation on upper trophic levels of many marine ecosystems stems from fishing. The reaction of the ecosystem goes beyond the trophic levels directly targeted by the fishery. This reaction has been described either as a change in slope of the overall size spectrum or as a trophic cascade triggered by the removal of top predators. Here we use a novel size- and trait-based model to explore how marine ecosystems might react to perturbations from different types of fishing pressure. The model explicitly resolves the whole life history of fish, from larvae to adults. The results show that fishing does not change the overall slope of the size spectrum, but depletes the largest individuals and induces trophic cascades. A trophic cascade can propagate both up and down in trophic levels driven by a combination of changes in predation mortality and food limitation. The cascade is damped as it comes further away from the perturbed trophic level. Fishing on several trophic levels leads to a disappearance of the signature of the trophic cascade. Differences in fishing patterns among ecosystems might influence whether a trophic cascade is observed.
许多海洋生态系统中上层营养级的最大扰动来自捕捞。生态系统的反应超出了渔业直接针对的营养级。这种反应要么被描述为整个大小谱的斜率变化，要么被描述为顶级捕食者移除引发的营养级联。在这里，我们使用一种新颖的基于大小和特征的模型来探索海洋生态系统可能如何对不同类型的捕捞压力做出反应。该模型明确地解决了鱼类从幼虫到成鱼的整个生命周期。结果表明，捕捞不会改变大小谱的整体斜率，但会消耗最大的个体并引发营养级联。在捕食死亡率和食物限制变化的共同作用下，营养级联可以在营养级上下传播。级联随着远离受扰的营养级而减弱。在几个营养级上进行捕捞会导致营养级联的特征消失。生态系统之间捕捞模式的差异可能会影响是否观察到营养级联。
