Publication Abstract

Calibration of FISK, an invasive-ness screening tool for non-native freshwater fishes

G.H. Copp*, L. Vilizzi, J. Mumford, G.V. Fenwick, M.J. Godard* and R.E. Gozlan

Adapted from the Weed Risk Assessment  (WRA) of Pheloung, Williams & Halloy, the Fish Invasiveness Scoring Kit (FISK) was proposed as a screening tool for freshwater fishes. The present paper describes improvements to FISK, in particular the incorporation of confidence (certainty/uncertainty) ranking of the assessorsÕ responses, and reports on the calibration of the score system, specifically: determination of most appropriate score thresholds for classifying non-native species into low, medium and high risk categories assessment of the patterns of assessorsÕ confidences in their responses in the FISK assessments. Using  Receiver operating characteristic (ROC) curves, FISK was demonstrated to distinguish accurately (and with statistical confidence) between potentially invasive and non-invasive species of non-native fishes, with the statistically appropriate threshold score for high risk species scores being ³19. Within the group of species classed as high risk using this new threshold, a ‘higher risk’ category could be visually identified, at present consisting of two species (topmouth gudgeon Pseudorasbora parva and gibel carp Carassius gibelio). FISK represents a useful and viable tool to aid decision and policy makers in assessing and classifying freshwater fishes according to their potential invasiveness.

Reference:
G.H. Copp*, L. Vilizzi, J. Mumford, G.V. Fenwick, M.J. Godard* and R.E. Gozlan (2000) Calibration of FISK, an invasive-ness screening tool for non-native freshwater fishes. Risk Analysis, 29; 457-467