Development of the risk ranking framework
The third step of the risk ranking process was to build a framework to score the included pathogens according to defined risk criteria. A semi-quantitative matrix based on the multicriteria decision analysis (MCDA) methodology was developed to identify the high-risk fish pathogens of concern (WHO and FAO 2007; Van der Fels-Klerx et al. 2018). MCDA methodology allows for the inclusion of different types of risk information, including empirical data and expert judgement. Risk ranking criteria were developed based on previous evaluations of the bait pathway (Boersen et al., 2017; J. L. Gunderson, 2018) and adapted to reflect the likelihood of pathogen occurrence and the severity of its impact due to spreading in the baitfish pathway. The MCDA risk ranking framework was comprised of seven risk criteria: likelihood of transfer, prevalence in the bait supply, colonization potential, ecological impact if established, economic impact if established, current distribution in Minnesota, and host species. Each criterion was assigned a normalized risk score based on available literature (0-3, Table 2). An unweighted risk score (assuming equal weight among all criteria) was calculated for each pathogen by adding each individual criterion score using the following equation:
\(Unweighted\ risk\ score=\sum_{i=1}^{7}S_{\text{ij}}\ \) (1)
where Sij is the score for pathogen j on criterion i . All data and calculations available in the Supporting Information.