May 3, 2011
MADISON - Requirements for oceangoing ships arriving in Wisconsin's Great Lakes waters have changed in two major ways that officials say will work together to better protect Wisconsin waters from invasive species.
Effective April 1, the Department of Natural Resources modified requirements in its general permit that oceangoing ships arriving in Wisconsin ports must have. The ships must:
"Canadian research suggests that combining ballast water exchange with the numerical standard by the International Maritime Organization may result in good protection for our Great Lakes and inland waters," says Laura Madsen, DNR coordinator of the ballast water permitting program.
"We think it's an effective one-two punch for aquatic invasive species that might be hitching a ride in ballast water."
Large commercial vessels take on and release water to help balance the vessel as cargo is loaded on and off; plants, animals and pathogens are sucked in as well and can be released in the Great Lakes. Releases of ballast water are the leading way invasive aquatic species such as the zebra mussel, quagga mussel and round goby have been introduced to the Great Lakes over the last century.
New research is showing that exchanging ballast water at sea can reduce by up to 95 percent the number of invasive species that have the greatest chance of surviving and causing trouble in freshwater bodies, according to Sarah Bailey, PhD. a research scientist for the Canadian federal government's Department of Fisheries and Oceans and a member of the Great Lakes Ballast Water Collaborative, a regional network of scientists and policymakers that Wisconsin asked to examine its treatment standard in 2010.
Older research had raised questions about the effectiveness of ballast water exchange and the variation among ships in how frequently and how well they preformed the process. But Bailey's research is showing that done right, the plants, animals and pathogens are purged at sea as the ballast water is exchanged; organisms remaining in the tank are then subjected to the salt water taken in, which kills and weakens many of them, Bailey says.
"We've been completing analysis of flushing and finding such exchange is much more protective of freshwater ports than marine ports," Bailey says. "This idea of combining exchange with treatment may be a more meaningful increase in protection because you're now addressing two of the three factors necessary for a successful invasion, not just one."
The ultimate success or failure of any introduction of a harmful aquatic invasive species or pathogen depends on how many of the particular species are released over time; whether the receiving water's temperature, salinity, dissolved oxygen, and other environmental conditions are hospitable to the invader; and whether the food and predator situation is conducive to its survival and growth, Bailey says.
Wisconsin started regulating large commercial vessels entering its Great Lakes waters in February 2010, joining Minnesota, Michigan and New York in doing so to provide greater protection than provided as a result of federal permit requirements. The federal government has taken more than a decade to develop ballast water regulations and they are still not done.
Wisconsin's ballast water discharge general permit called for phasing in a requirement that new and existing oceangoing ships meet a treatment standard 100 times higher than the IMO standard. DNR was required to determine, by the end of 2010, if effective treatment systems would be available by the implementation date, and if not, revert to the IMO standard.
DNR engaged the Great Lakes Ballast Water Collaborative (Collaborative), a group of experts from academia, government, the shipping industry, testing facilities, treatment vendors and nonprofit organizations to review ballast water treatment technologies. The group concluded in a report (pdf) that technology did not yet exist to verify whether a treatment system can rid ballast water of organisms effectively enough to meet the original Wisconsin standard.
"The technology is not quite there to support the higher standard. The good news is that research is showing that existing technologies may be more effective, and more protective, for freshwater systems than we thought," Madsen says.
More information on ballast water is available in a media kit on the DNR website.
FOR MORE INFORMATION CONTACT: Laura Madsen - (608) 264-6285