The Fish Invasiveness Screening Kit (FISK) for non-native freshwater fishes--a summary of current applications.

A major step forward in the screening of nonnative species came with the development of the weed risk assessment (WRA) of Pheloung et al.(1) for terrestrial plants of Australia and New Zealand. Based on the generally accepted premise that weeds in one part of the world will have an increased chance of being weedy (i.e., invasive) in other areas with similar environmental conditions, the WRA’s question and answer scoring system provided a conceptual, semi-quantitative basis from which to develop similar screening tools for a range of aquatic species.(2) Funded by the U.K. Department of Environment, Food and Rural Affairs (Defra), five screening tools were developed from the WRA template, with permission from the original authors of the WRA: the freshwater Fish Invasiveness Screening Kit (FISK), a variation of FISK for non-native marine fishes (MFISK), the Freshwater Invertebrate Invasiveness Screening Kit (FI-ISK), a variation of FI-ISK for marine invertebrates (MI-ISK), and the Amphibian Invasiveness Screening Kit. Of these, the FISK for freshwater fishes was the first to be calibrated,(3) with subsequent applications of FISK in Belgium,(4) Belarus,(5) Japan,(6) Brazil,(7) and Mexico.(8) All but one of these subsequent applications involved a single assessor for each species, and the threshold value (i.e., 19.0) from the initial U.K. calibration(3) was used to distinguish between species classed as medium or as high risk of being invasive. The initial FISK calibration involved two assessors and focused specifically on England and Wales as the “risk