Problem formulation and scoping
A multi-step process centered around expert stakeholder input was designed for the risk ranking exercise (Table 1). As first step, an initial cluster of stakeholder-experts with expertise in fish health and aquatic invasive species prevention were identified from the Minnesota Department of Natural Resources (MNDNR) to provide input throughout the process and to ensure study outcomes aligned with the state management objectives.
Best practices indicate that clarifying the objective, question, or endpoint of interest is critical for the accuracy and applicability of a risk assessment (Jakob-Hoff et al., 2014). Therefore, the second step of the risk ranking exercise was to define the primary question of the analysis, which was formulated as: “What pathogens are most likely to present a risk to the health of wild fish via release of infected baitfish?” Although there is some evidence that potential human and wildlife pathogens (Mahon et al. 2018; Picco et al. 2010) may be present in live baitfish, the scope of this study was limited to pathogens of fish. After the definition of the project question, an initial list of pathogens to be assessed was obtained from existing qualitative evaluations (Boersen et al. 2017; Gunderson 2018) and lists of important (regulatory) fish pathogens curated by the OIE (Aquatic Animal Health Code, OIE) and Minnesota law (MN Statute 17.4982). Inclusion/exclusion criteria were developed based on host susceptibility for the initial hosts, live baitfish that could be legally used in Minnesota as listed in the 2018 fishing regulations handbook (accessible at https://files.dnr.state.mn.us/rlp/regulations/fishing/fishing_regs.pdf), and the recipient population (described as “fish of concern”), which included game fish, fish listed as threatened or endangered by the Minnesota Endangered Species Statute (MN Statute 84.0895), or fish receiving management attention from MNDNR (Figure 1).