Data from: On the occurrence of three non-native cichlid species including the first record of a feral population of Pelmatolapia (Tilapia) mariae (Boulenger, 1899) in Europe

Thermally influenced freshwater systems provide suitable conditions for non-native species of tropical and subtropical origin to survive and form proliferating populations beyond their native ranges. In Germany, non-native convict cichlids (Amatitlania nigrofasciata) and tilapia (Oreochromis sp.) have established populations in the Gillbach, a small stream that receives warm water discharge from a local power plant. Here, we report on the discovery of spotted tilapia (Pelmatolapia mariae) in the Gillbach, the first record of a reproducing population of this species in Europe. It has been hypothesized that Oreochromis sp. in the Gillbach are descendants of aquaculture escapees and our mtDNA analysis found both O. mossambicus and O. niloticus maternal lineages, which are commonly used for hybrids in aquaculture. Convict cichlids and spotted tilapia were most probably introduced into the Gillbach by aquarium hobbyists. Despite their high invasiveness worldwide, we argue that all three cichlid species are unlikely to spread and persist permanently beyond the thermally influenced range of the Gillbach river system. However, convict cichlids from the Gillbach are known to host both native and non-native fish parasites and thus, non-native cichlids may constitute threats to the native fish fauna. We therefore strongly recommend continuous monitoring of the Gillbach and similar systems.

受热影响的淡水生态系统可为热带及亚热带起源的外来物种提供适宜生存条件，使其能在原生分布范围之外形成增殖种群。在德国，外来物种九间始丽鱼（Amatitlania nigrofasciata）与罗非鱼（Oreochromis sp.）已在吉尔巴赫河（Gillbach）建立种群，该小型溪流接纳了当地发电厂排放的温热水。本研究首次报道在吉尔巴赫河中发现斑点罗非鱼（Pelmatolapia mariae），这是该物种在欧洲的首个可繁殖种群记录。此前有假说认为，吉尔巴赫河中的罗非鱼（Oreochromis sp.）为水产养殖逃逸个体的后代，本研究的线粒体DNA（mtDNA）分析显示，其存在莫桑比克罗非鱼（Oreochromis mossambicus）与尼罗罗非鱼（Oreochromis niloticus）的母系谱系——这两种鱼类常被用于培育水产养殖杂交品种。九间始丽鱼与斑点罗非鱼极有可能是通过水族爱好者引入吉尔巴赫河的。尽管这三个物种在全球范围内均具有较高入侵性，但我们认为，三种丽鱼科物种不太可能永久扩散并存活于吉尔巴赫河系统的受热影响范围之外。不过，已知吉尔巴赫河的九间始丽鱼可携带本土与外来鱼类寄生虫，因此外来丽鱼科物种可能对本土鱼类群落构成威胁。据此，我们强烈建议对吉尔巴赫河及类似生态系统开展持续监测。