Identifying the species that are likely to have a significant ecological and/or socio-economic impact if they are introduced, or spread to new parts of the basin, is an important foundation of a regional surveillance program and can help inform what to look for and where to look. 

Development of a watchlist of priority surveillance species should be based on the probability of introduction, establishment, and impact in the Great Lakes. Only those species that are present in an active pathway of introduction (such as the aquarium trade or recreational boating), can establish self-sustaining populations, and are likely to have a high or moderate ecological and/or socio-economic impact would be considered a high-risk species.

A surveillance watch list can also help inform which habitats we need to sample and what sampling methods, sampling strategies and sampling frequency we should deploy to increase our likelihood of identifying and addressing these species early and increase the potential for a successful management response.