Invasiveness screening of non-native fishes for the middle reach of the Yarlung Zangbo River, Tibetan Plateau, China

The aim of this study was to identify potentially invasive non-native freshwater fishes in the middle reach of the Yarlung Zangbo River, Tibetan Plateau (China), using the Aquatic Species Invasiveness Screening Kit (AS-ISK), as decision-support tool. Based on independent evaluations of 24 non-native freshwater fishes, receiver operating curve analysis identified a threshold score of 29 for distinguishing species likely to pose a high risk of becoming invasive from species likely to pose low-to-medium risk (<29) in the risk assessment area. Nine species were categorized as high risk: goldfish Carassius auratus, topmouth gudgeon Pseudorasbora parva, brook trout Salvelinus fontinalis, Oriental weatherfish (a.k.a. dojo gudgeon) Misgurnus anguillicaudatus, Siberian taimen Hucho taimen, common carp Cyprinus carpio, peled Coregonus peled, western mosquitofish Gambusia affinis, and Chinese rice fish Oryzias sinensis. The three lowest scoring species were Arctic cisco Coregonus autumnalis, Wuchang bream Megalobrama amblycephala, and Chinese ice fish Neosalanx taihuensis, which are unlikely to be invasive because they are unable to complete their life cycle in the risk assessment area. Climate change assessments scores increased or remained the same for warm-water species and decreased for coldwater species. This study was the first application of AS-ISK in western China, and the results suggest that AS-ISK is a useful and valid tool for identifying potentially invasive risk aquatic species in China.