CMIST is a peer-reviewed screening-level risk assessment tool for marine invasive species (Drolet et al. 2016). It is a short questionnaire that follows the invasion process from arrival to impact and is designed so an informed assessor can evaluate one species in an assessment area in approximately one day using easily accessible information from internet databases, primary literature, and grey literature. Species can be those with an invasion history in an area or those that are candidates for future invasions.

CMIST is score-based and incorporates both likelihood and impact of invasion as well as uncertainty. Questions are general to make CMIST broadly applicable to different taxa, different assessment areas, and different project goals. To date, CMIST has been tested with molluscs, tunicates, crustaceans, and polychaetes introduced or at risk of introduction to three Canadian marine ecoregions (DFO 2009). CMIST has also been successfully applied to non-indigenous freshwater fish in British Columbia with adapted guidelines (T. Therriault, pers. comm.). Upon completion, CMIST produces a risk score adjusted for the assessor’s uncertainty which, combined with information collected during the assessment, can be used to assist in management decisions. For example, in 2015, CMIST assessments were used to identify high risk invaders in three Canadian marine ecoregions (DFO 2016).

Development of CMIST

CMIST was developed by Fisheries and Oceans Canada (DFO) over the course of several years and multiple phases. In 2011, DFO’s Aquatic Invasive Species program was tasked by the Office of the Auditor General and an internal evaluation to establish a scientifically defensible and relatively quick protocol to screen and prioritize high risk aquatic non-indigenous species (NIS). In addition, DFO’s Ecosystem and Fisheries Management (EFM) requested science advice to support national regulations to address aquatic NIS, including a protocol to identify and prioritize high risk aquatic NIS. In response, a national Canadian Science Advisory Secretariat (CSAS) science advisory process was initiated to provide science advice on screening-level risk assessment (SLRA) prioritization tools for freshwater and marine NIS.

Part 1 was held in Montréal, Quebec, from 22 to 24 November 2011, where participants compared SLRA protocols and developed a framework for a new SLRA tool for aquatic NIS, referred to as the Montreal Rapid Assessment Tool (Montreal-RAT) (DFO 2012). This tool was eventually modified into CMIST. In Part 2 in Burlington, Ontario, from 19 to 21 March 2013, SLRA protocols were evaluated for and applied to three freshwater NIS taxa (DFO 2014a, 2014b, Snyder et al. 2013). In Part 3 in Halifax, Nova Scotia, from 4 to 6 February 2015, a national peer review on the Marine Screening-Level Risk Assessment Protocol for Aquatic Non-Indigenous Species reviewed the newly developed marine SLRA tool CMIST as applied to identify the potential risk associated with NIS invertebrates (molluscs, tunicates, crustaceans, and polychaetes) already introduced and others not reported in three Canadian marine ecoregions (Gulf of St. Lawrence, Scotian Shelf, and Strait of Georgia) (DFO 2016, 2015). In total, 60 species–ecoregion combinations for species already introduced were assessed by two assessors, and outputs were compared to expert knowledge of species-ecoregion invasion outcomes. For species not reported from these three Canadian ecoregions, 45 species-ecoregion combinations were assessed to estimate invasion risk. In addition, novel methods for incorporating uncertainty into risk scores were explored.

CMIST was considered a scientifically defensible and practical tool to screen and prioritize marine invertebrates, both for those already introduced and those not reported in Canadian marine ecoregions. In addition, because CMIST questions are generalized to the invasion process and resulting impacts, this tool could be applied to other taxa. For more background information on CMIST development please consult DFO (2015).