Alien species of fish in freshwater ichthyofauna of the Crimea

Abstract

Overview of changes that occurred in the inland waters of the Crimea is presented, and the introduction and naturalization of alien fish species, associated with this process, is studied. Approximately 55 new fish species were registered in the last 70 years in rivers, reservoirs, canals, and ponds of the peninsula. They can be attributed to four groups according to their abundance: (1) their findings are single, (2) they lived in the waters during several decades and disappeared over a given period, (3) their presence and number depends on aquaculture activities, and (4) they created sustainable self-reproducing populations. Currently, at least 27 species of fish can be considered as naturalized. The distribution and quantitative characteristics of alien species in the rivers and reservoirs of the North Crimean channel and their relationship with biotopical and hydrological characteristics of the habitats are analyzed.