Notre Dame’s Science-Based Tools for Assessing Invasion Risk (STAIR): Fish
This tool focuses on the ability of a species to move through the stages of invasion—from introduced to established to invasive. We began by identifying which traits allow a species to transition from introduced to established, which we define as having sustained, reproducing populations. To do this, we gathered ecological, biological and taxonomic information on the 65 fish species that have been introduced into the Great Lakes. We analyzed these data and found that the match between the climate of the Great Lakes and the known range of a given species is the best predictor for whether it will become established; if the climate match is greater than 71.7 percent, then the species is likely to become established. Evaluation of this relationship demonstrated that it results in accurate predictions 78 percent of the time.
We next determined which characteristics allow a species to move from established to invasive, which we define as causing ecological harm. We began by surveying Great Lakes fishery experts about established species and their perceived harm. We used these data to rank all established species from least to most ecologically harmful then analyzed these rankings together with the trait data. Species that were considered to cause negligible or minor harm were designated low impact. Species considered to cause significant harm were designated high impact. We found that the trophic guild of the adults was the primary trait responsible for these impact levels; piscivores are very likely to be invasive and non-piscivores will only become invasive if the females produce over 1,013,000 eggs per year.
The paper that details this tool and its development can be obtained here or by contacting Reuben Keller, one of its authors. STAIRfish was developed by experts from the University of Notre Dame, Loyola University Chicago, the University of Washington, Fisheries and Oceans Canada, Virginia Tech and St. Mary’s College of California.
The quality of any risk assessment depends on the information used to answer the tool’s questions. Using the best available data—scientific journals, species accounts in books, and expert opinion—to answer each question will provide the best results.