ABSTRACT: As the common carp Cyprinus carpio and African catfish Clarias gariepinus affect biotic assemblages in aquatic ecosystems through their benthivory, their introduction has been considered an environmental concern. We compare the effects of common carp and African catfish on adjacent trophic level assemblages of plankton, periphyton, benthic macroinvertebrates and native tilapia in a pond ecosystem at the National Aquaculture Center, Zomba, Malawi. Four treatments were involved in the study: ponds with common carp (T1), ponds with African catfish (T2), ponds with both common carp and African catfish (T3), and ponds lacking both common carp and African catfish (T4). In all treatments, the endemic Shire tilapia Oreochromis shiranus was also present as part of the local macrofauna. Results showed that T1 had the most abundant phytoplankton but the lowest periphyton, zooplankton and benthic macroinvertebrate abundance and diversity. T4 had the least phytoplankton but the most abundant and diverse zooplankton, periphyton and benthic macroinvertebrates. There was no significant difference between T2 and T3 (both intermediate to T1 and T4) in terms of phytoplankton, periphyton and benthic macroinvertebrate abundance and diversity. Better water quality regime and increased biomass of native tilapia fish were observed in T3 ponds. We conclude that the farming of common carp in aquatic ecosystems containing African catfish may not adversely affect the environment and that the polyculture of African catfish and common carp can be adopted as a management strategy to mitigate the potential adverse effects of common carp.

中文翻译：

---

鲤鱼和非洲cat鱼对池塘生态系统中浮游生物，附生植物和底栖大型无脊椎动物的影响

摘要：由于鲤鱼鲤鱼和非洲Cl鱼Clarias gariepinus通过底栖动物影响水生生态系统中的生物群落，因此将其引入已被视为对环境的关注。我们在国家水产养殖中心（马拉维，赞比亚）的池塘生态系统中比较了鲤鱼和非洲cat鱼对相邻营养级浮游生物，附生生物，底栖大型无脊椎动物和罗非鱼的影响。该研究涉及四种处理方法：鲤鱼池塘（T1），非洲cat鱼池塘（T2），鲤鱼和非洲cat鱼兼有的池塘（T3）以及鲤鱼和非洲cat鱼均缺乏的池塘（T4）。在所有治疗中，地方性夏尔罗非鱼Oreochromis shiranus也是当地大型动物的一部分。结果表明，T1的浮游植物数量最多，而浮游动物，浮游动物和底栖大型无脊椎动物的丰富度和多样性最低。T4的浮游植物最少，但浮游动物，周生植物和底栖大型无脊椎动物最多，种类最多。在浮游植物，周生植物和底栖大型无脊椎动物的丰富度和多样性方面，T2和T3（在T1和T4中间）之间没有显着差异。在T3池塘中观察到更好的水质状况和本地罗非鱼的生物量增加。