Evaluating the potential for invasion by alien freshwater fishes in northern Kyushu Island, Japan, using the Fish Invasiveness Scoring Kit

The potential invasiveness of 28 freshwater fishes in northern Kyushu Island, Japan, was evaluated using the Fish Invasiveness Scoring Kit (FISK). The five co-authors scored the level of invasiveness for each species and calculated the total FISK scores; the maximum and minimum scores were then eliminated, and the mean of the remaining three scores was used as the final score for each species. The mean scores ranged from 11.0 (Hypomesus nipponensis) to 31.0 (Cyprinus carpio). The receiver operating characteristic curve indicated that the threshold value between fishes that present a high risk of invasion and the other species were 19.8.