In February I blogged here about the U.S. Supreme Court’s failure to protect the Great Lakes from invasion by the Asian carp, which have the potential to further decimate native species and cost millions in economic losses and recovery efforts.
I’ve been drawn to the study of invasive species for many reasons. Study and management are multidisciplinary, requiring collaboration between scientists, policy makers and government, industry, farmers and fisherman, recreation, and the public. No solution is black and white and understanding must occur at both the global and microscopic level to develop complex solutions that often completely satisfy no one.
In a recent study, researchers from two American universities and one in the Netherlands have collaborated to calculate the approximate annual financial losses due not to the Asian carp that is poised to invade, but instead to other invasive species contained in the ballast water of ocean-going vessels that travel in Great Lakes water bodies. Researchers estimate that damages are $138 to $800 million annually, an underestimate that does not include Canadian costs.
Ballast water is simply fresh or sea water taken in and out of the holds and tanks of ships to manage stability and maneuverability during transport and the loading and unloading of cargo. Although ballast water discharge regulations were developed by an international convention in 2004, enforcement by the U.S. Coast Guard is imperfect. Appropriate ballast water discharge should occur in high seas (over 2000 meters in depth) or through chemical or mechanical treatment when seas are low and all discharges are to be logged.
Despite recent regulation, several invasive species have been transported throughout the world via ballast water. The U.S. Environmental Protection Agency estimates that 30% of invasive species in the Great Lakes were introduced via ballast water discharges. At least 25 non-native fish species have been introduced to the Great Lakes via ballast water since the 1800’s. First discovered in 1988, and now widespread in the U.S. and Canada, the zebra mussel (Dreissena polymorpha) was introduced via ballast water from the Caspian and Black Seas of Asia. A single sea lamprey, originally native to the Atlantic Ocean, also kills about 40 lbs. of Great Lakes fish in its life time, preferring lake trout, salmon, rainbow trout (steelhead), whitefish, chubs, burbot, walleye, catfish, and sturgeon.
A more recent trend, scientists and economists believe that converting environmental impacts to dollar values will help policy makers in cost/benefit analysis of future policy changes, management and prevention, and mitigation efforts. Similar approaches are being used to determine the most cost-effective approaches to control and mitigate global climate change. The numbers in the above study were used, for example, to evaluate the potential benefit of switching away from shipping toward other modes of transportation, noting that the switch could pencil out in our financial favor in less than 30 to 50 years. The real question is, can we wait that long?