Non-native fishes of Belarus: Diversity, distribution, and risk classification using the Fish Invasiveness Screening Kit (FISK)

As of the end of 2008, 25 species of non-native fishes have been documented in the Republic of Belarus. Of these, 17 (68%) species were deliberately introduced for aquaculture, six (24%) species invaded from the adjacent territories by natural dispersal, and two (8%) species were likely introduced accidentally. During the 20th century, the number of non-native fishes in Belarus increased exponentially, resulting in significant shifts in taxonomic composition of the country's ichthyofauna. For the first time, we assessed the invasive potential of the introduced fishes by applying a uniform protocol, the Fish Invasiveness Screening Kit (FISK). Based on the total FISK scores, all the non-native fishes in Belarus were classified into two groups: high and medium risk of becoming invasive. In terms of the economic sectors at risk ('aquacultural/fisheries', 'environmental', and 'nuisance'), all species were classified into three distinct groups. The highest risk to all of these sectors was posed by the brown bullhead Ameiurus nebulosus Le Sueur, 1819, gibel carp Carassius gibelio (Bloch, 1782), round goby Neogobius melanostomus (Pallas, 1814), Amur sleeper Perccottus glenii Dybowski, 1877, and topmouth gudgeon Pseudorasbora parva (Temminck & Schlegel, 1846). The two risk categories identified in the present study can be used in prioritizing the resources for the management of non-native fish species of Belarus and in countries with similar environmental conditions.