This is one the best pieces of journalism ever done on the problem of controlling invasive species in ballast water.
That voluntary rule has since become mandatory, and while everybody agrees that this is a good practice, most also agree it doesn't go nearly far enough in protecting the Great Lakes from the next zebra mussel, or quagga mussel, or round goby, or ruffe, or spiny waterflea - all Great Lakes invaders scientists blame on ballast spills during the last three decades.
The reason: As many as 90% of the oceangoing ships arriving in the St. Lawrence Seaway are loaded with cargo and therefore don't officially carry ballast, and that exempts them from the ballast exchange law.
Yet those "empty" ballast tanks hold permanent puddles, some of which contain nearly 10,000 gallons of water, as well as tons of muck teeming with life. Ships arrive at their first port of call on the Great Lakes, unload their foreign cargo, then take on ballast water to get to the next Great Lakes port. When they reach that port, they dump that ballast in exchange for cargo. That's when species can literally jump ship and invade the lakes.
This is not a theoretical problem. Data show that, despite the ballast exchange requirement, a new invasive species continues to be discovered, on average, every 6 1/2 months.
http://www.jsonline.com/news/state/oct05/366877.asp
Posted by Dave at October 31, 2005 10:50 AM