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.