INTRODUCED FISH SPECIES IN POLAND: PROS AND CONS

Abstract

The paper reviews the history of introductions, the occurrence of exotic fishes in inland waters of Poland, and costs and benefits of introductions. 23 exotic fish species occur permanently or seasonally in natural water bodies (rivers, lakes), which constitutes about 30%of the whole Polish ichthyofauna. In the absolute majority of introductions a negative influence of exotic species has been recorded, both on the native fish communities and aquatic environment. The introductions of merely a few species (rainbow trout, carp, herbivorous fishes) can be regarded as fully successful as only in their case the increase in fish production obatined was considerable (mainly in aquaculture).