Ecological aspects of the introduction of fish species into natural habitats in Europe, with special reference to the Netherlands

A total of 39 fish species has been introduced into European waters, mainly during the 19th and 20th centuries: 20 European species (12 successful), 3 Asian species (1 successful), 16 North American species (13 successful). Several successful introductions have produced unexpected and detrimental side-effects; especially introductions of piscivorous species have created problems. Introductions of the latter type of fishes should be most carefully considered. The aim of fish introductions should preferably be to create temporary populations of non-reproducing fishes whose numbers can be completely controlled by man.