Risk screening of non‐native, translocated and traded aquarium freshwater fishes in Greece using Fish Invasiveness Screening Kit

The invasion of non‐indigenous freshwater fish species is one of the most important threats to aquatic biodiversity. Similar to other Mediterranean countries, Greece is considered a hot spot for freshwater biodiversity, with many range‐restricted endemics of high conservation concern. The aim of this study was to undertake a risk screening assessment to evaluate the invasive potential of non‐native, translocated and traded aquarium fishes in Greece by applying the Fish Invasiveness Screening Kit (FISK). In total, 73 freshwater fish species were evaluated by two assessors. FISK was able to discriminate reliably between invasive and non‐invasive species with a threshold of 15.25. Based on mean scores, 30 species were classified as ‘high risk’, of which 17 as ‘moderately high risk’, six as ‘high risk’ and seven as ‘very high risk’. There was a high coincidence rate for the species categorisation between the two assessors, but significant differences in certainty. The results suggest that FISK is a useful tool for assessing risks posed by non‐native, translocated and traded aquarium fish species in Greece.