ABSTRACT: Freshwater pond polyculture faces many challenges in Europe. Appropriate tools must be developed to better understand and manage trophic interactions in pond ecosystems. The objective of our study was to understand the trophic interactions and make inference on the fish diet in common carp polyculture through a combination of experiments and trophic web modeling. We conducted an experiment in small fishponds of common carp polyculture reared with roach and perch and used Ecopath with Ecosim software to characterize the food web. Two replicates of 3 treatments were performed: a semi-extensive pond with low fish density and no formulated feed, an intensive pond with twice the fish density and formulated feed and an intensive pond coupled with a planted lagoon. Ten trophic groups were defined to describe the food web. The modeling procedure enabled us to estimate the diets of each trophic group. The fish diet in fed and non-fed treatments differed greatly since the carp fed mainly on formulated feed when available. The roach exhibited trophic plasticity by adapting their diet to the available resources. The benthic macroinvertebrates and zooplankton were preyed upon intensively; they became the limiting factors for fish production and depended on phytoplankton availability. Detritus and phytoplankton were the main sources of nutrients in all treatments but were not used efficiently. These results provide several insights for improving polyculture. In particular, they promote better management of zooplankton and macroinvertebrates as food sources for target species and a better balance in fish assemblages for more efficient use of resources.

中文翻译：

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使用 Ecopath 模拟淡水鱼塘系统中的营养网：实现更好的混养管理

摘要：淡水池塘混养在欧洲面临许多挑战。必须开发适当的工具以更好地了解和管理池塘生态系统中的营养相互作用。我们研究的目的是通过实验和营养网建模相结合，了解营养相互作用并推断鲤鱼混养中的鱼类饮食。我们在用蟑螂和鲈鱼饲养的鲤鱼混养的小鱼塘中进行了一项实验，并使用 Ecopath 和 Ecosim 软件来表征食物网。进行了 3 个处理的两个重复：一个鱼密度低且没有配合饲料的半粗养池塘，一个鱼密度和配合饲料两倍的集约化池塘，以及一个与人工泻湖相结合的集约化池塘。定义了十个营养组来描述食物网。建模程序使我们能够估计每个营养组的饮食。喂食和非喂食处理中的鱼饲料差异很大，因为鲤鱼主要以可用的配合饲料喂养。蟑螂通过使它们的饮食适应可用资源而表现出营养可塑性。底栖大型无脊椎动物和浮游动物受到密集捕食；它们成为鱼类生产的限制因素，并取决于浮游植物的可用性。碎屑和浮游植物是所有处理中营养的主要来源，但没有得到有效利用。这些结果为改进混养提供了一些见解。特别是，它们促进了对作为目标物种食物来源的浮游动物和大型无脊椎动物的更好管理，并促进了鱼类组合的更好平衡，以更有效地利用资源。