Alien Freshwater Fishes of Europe

Abstract

A total of at least 76 alien freshwater fish species belonging to 21 families have been introduced into European fresh waters. The majority of them originate from North America (34) and Asia (26). Most introductions have been successful at least in one country. Nowadays at least 50 originally non-European freshwater fish species inhabit European fresh waters in self-sustaining populations. Economically most important invasive species are Oncorhynchus mykiss, Salvelinus fontinalis, Ctenopharyngodon idellus, Aristichthys nobilis and Hypophthalmichthys molitrix. These species may form 20–30% of the catch in several areas and Oncorhynchus my kiss is very important for aquaculture. In most cases the ecological impacts of invasive species have been small. However East Asian carps, especially Ctenopharyngodon idellus have caused considerable changes in native ecosystems and fishes by eliminating aquatic macrophytes and by resuspending sediment increasing water turbidity. Also predation and competition by invasive species have caused reductions and collapses of native fish populations.