Invasive species are non-native species that have established populations in regions beyond which they evolved . These species, ranging from plants to mammals to infectious organisms, can cause considerable economic damage and ecological damage in the regions that they invade . Aquatic invasive species (AIS) are of particular interest because they can easily spread once they have entered a new aquatic ecosystem. These species can be transported either intentionally (e.g. fish stocking) or unintentionally (e.g. ballast water) through various vectors of introduction . To get a better idea of the basics of invasive species, have a look at the video below.
A brief introduction to invasive species.
There has been a documented connection between international trade, economic growth, and the number of invasive species introduced worldwide . (See figure 1 below.) Numerous trade agreements have facilitated international trade (e.g. NAFTA, GATT) and although the intention wasn’t there, they have effectively provided an avenue for the transportation of invasive species around the world. Through international trade and globalization, the earth has become irrevocably interconnected, and as such, it becomes difficult to approach the problem of invasive species at the national level considering it can be such a transboundary problem . Several attempts around the world have successfully and unsuccessfully created and implemented numerous regulations to improve the invasive species situation, but there is still a lack of overall agreement or harmonization between countries .
The following quote demonstrates our current inability to deal with this issue:
“Unfortunately, scientific knowledge and institutional mechanisms are currently insufficient to effectively, predict, prevent, or mitigate the impacts of invasive species […].” .
So how do we deal with this issue? In an ideal world, transboundary environmental impact assessment (TEIA) would provide an excellent framework upon which to prevent species invasions and therefore their impact. This could be that scientific and institutional solution we’ve all been searching for. Keep in mind the use of the word “ideal”. Although the harmonization process has been slow going because of a reluctance to adopt international standards, some multinational collaborations provide hope for the future, such as the OSPAR Commission. Prediction and mitigation of impacts are central to the process of EIA . A TEIA process should be required for major vectors of transportation of invasive species, including transoceanic shipping, aquaculture, and fish stocking, but also especially for those that involve the deliberate moving of species. Predicting the impacts of invasive species can be a complex task , but from the perspective of the precautionary principle, it is best to not take a chance and therefore focus on prevention. Following a TEIA process would be an excellent start to an ongoing debate on how to prevent further species invasions and minimize their impacts, and would provide a replicable process for many countries to follow in the future.
 Burgiel, S., G. Foote, M. Orellana, A. Perrault. (2006). “Invasive species and trade: integrating prevention measures and international trade rules.” Retrieved October 14th, 2012 from http://www.pijac.org/_documents/4_-_invasive_alien_species_and_trade_-_burgiel_foote_doc.pdf.
 Pimental, D., R. Zuniga, and D. Morrison. (2005). “Update on the environmental and economic costs associated with alien-invasive species in the United States.” Ecological Economics 52(3): 273-288.
 Holeck, K.T., E.L. Mills, H.J. MacIsaac, M.R. Dochoda, R.I. Colautti, and A. Ricciardi. (2004). “Bridging troubled waters: Biological invasions, transoceanic shipping, and the Laurentian Great Lakes.” BioScience 54(10): 919-929.
 Tweedie, J. (2006). “Transboundary environmental impact assessment under the North American Free Trade Agreement.” Washington and Lee Law Review 63(2): 850-909.
 Noble, B.F. (2010). “Introduction to Environmental Assessment: A guide to Principles and Practice. Second Edition.” Oxford University Press: 274p.