Evaluation of the Fish Invasiveness Screening Kit (FISK v2) for peninsular Florida

The Fish Invasiveness Screening Kit (FISK) is becoming a popular tool for rapid risk identification of freshwater fishes, with published applications now spanning the globe. Upgrades (i.e., FISK v2) were completed recently to ensure the incorporation of broader climatic zones for its application to the sub-tropical climate of peninsular Florida. The goal of the present study was to evaluate the ability of FISK v2 to identify the potential risk of non-native fishes being invasive in peninsular Florida. The 95 fishes selected for screening were assigned an independent invasiveness ranking using information provided by FishBase and the Invasive Species Specialist Group database. Risk screenings using FISK v2 were then completed separately and independently by five assessors resulting in one to five screenings per taxon. Receiver operating characteristic (ROC) analysis identified a mean threshold value of 10.25 to distinguish between invasive fishes and non-invasive fishes, which, when compared to the independent invasiveness standard, correctly classified 76% of invasive fishes and 88% of non-invasive fishes. This threshold value was considerably lower than many other published calibrations of FISK, emphasizing the importance of regionally focused risk screening. Further supporting these results, 18 (72%) of the high risk species are either established in Florida or have elevated regulatory status by the Florida Fish and Wildlife Conservation Commission. Overall, FISK v2 has proved that it would be a valuable tool for informing management decisions related to the risks of non-native freshwater fishes.