Data from: Species’ ecological functionality alters the outcome of fish stocking success predicted by a food-web model

Fish stocking is used worldwide in conservation and management but its effects on food-web dynamics and ecosystem stability are poorly known. To better understand these effects and predict the outcomes of stocking, we used an empirically validated network model of a well-studied lake ecosystem. We simulate two stocking scenarios with two native fish species valuable for fishing. In the first scenario, we stock planktivorous fish (whitefish) larvae in the ecosystem. This leads to 1% increase in adult whitefish biomasses and decreases the biomasses of the top predator (perch). In the second scenario, we also stock perch larvae in the ecosystem. This decreases the planktivorous whitefish and the oldest top predator age class biomasses, and destabilizes the ecosystem. Our results demonstrate that the effects of stocking depend on the species’ position in the food web and thus cannot be assessed without considering interacting species. We further show that stocking can lead to undesired outcomes from both management and conservation perspectives. The gains of stocking can remain minor and have adverse effects on the entire ecosystem.鱼类放养（Fish stocking）在全球范围内被广泛应用于物种保护与渔业资源管理，但当前学界对其如何影响食物网（food-web）动态及生态系统稳定性（ecosystem stability）的认知仍较为匮乏。为更深入地阐明此类影响并精准预测放养措施的实施效果，本研究采用了针对某一已被充分研究的湖泊生态系统构建的、经实证验证的食物网模型。本研究针对两种兼具渔业价值的本土鱼类设置了两组放养模拟场景：在第一组场景中，我们向该生态系统中投放浮游食性鱼类（planktivorous fish）白鲑（whitefish）的幼体，该操作可使成年白鲑的生物量（biomass）提升1%，同时降低顶级捕食者（top predator）鲈鱼（perch）的生物量；在第二组场景中，我们额外向该生态系统中投放鲈鱼幼体，此操作会降低浮游食性白鲑以及最年长年龄组顶级捕食者的生物量，并破坏生态系统的稳定性。本研究结果表明，鱼类放养的影响取决于目标物种在食物网中的生态位，因此若不考虑物种间的相互作用，则无法准确评估其放养效果。本研究进一步证实，从资源管理与物种保护的双重视角来看，鱼类放养均可能产生非预期的负面结果，其所能带来的收益往往十分有限，反而会对整个生态系统产生负面影响。