Economic impact of invasives in the Great Lakes

The Great Lakes represent a globally significant freshwater reservoir that provides benefits in the form of recreation, fishing, transportation services, jobs, climate regulation, fish and wildlife habitat, and of course, water supply. And yet, the Great Lakes and regional economy are under siege from a seemingly inconspicuous threat – non-native species introduced by ocean-going ships. To date, there have been around 57 species introduced to the Great Lakes with a heavy cost.

A new economic analysis has quantified these results, revealing median costs at around US$138 million a year. Published in the journal Ecosystems, this research from the University of Notre Dame estimates the biological and economic impacts of invasive species introduced by boats. Invasive species are non-native species that threaten native species and ecosystems or otherwise cause a negative impact on activities like aquaculture or recreation. And at an annual cost of $138 million, this analysis provides a convincing case to invest in reducing the invasion of ship-borne organisms in the Great Lakes. 

To obtain their findings, the authors used something called structured expert judgment. They relied on relevant research and professional opinions from experts on a specific topic in order to produce estimates of value based on points of interest, or in this case, ecosystem services. Ecosystem services are the benefits that come from ecosystems and natural resources. This study focused on four ecosystem services – commercial fish landing, sportfishing participation, wildlife viewing, and raw water usage. These services were chosen for being important to the regional economy and because historical data was available and reliable.
 
This study provides valuable economic insight into the consequences of invasive species in the Great Lakes. It enables a more rigorous cost-benefit analysis of policies and programs that would either address the transport of alien species or the continuation of the status quo.  This analysis enables policy makers to make informed decisions based on quantified estimates of risk and future damages, and continues to provide a rationale for incorporating the benefits of ecosystem services into policies and programs on conservation and resource management.