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Battling the Ballast Water
by Marcia Goodrich
For David Hand, the line between work and play is as thin as monofilament. This is evident from the trophy lake trout on his office wall and in the passion that charges his voice when he talks about a deadly threat to his beloved Lake Superior fishery.
Since 2003, viral hemorrhagic septicemia (VHS) has caused massive die-offs of fish species ranging from walleyes to salmon in all of the Great Lakes—except Superior. Infected fish die from internal bleeding and often have open sores and bruised-looking, reddish tints on their skin.
The virus that causes VHS is just one of dozens of exotic species that have invaded the Great Lakes since the St. Lawrence Seaway opened in 1959, bringing boats, trade, and money, not to mention parasitic sea lampreys and the like, to the heretofore landlocked Midwest. Many of these pests are unwelcome hitchhikers in the ballast water of vessels ranging from pleasure craft to ore boats.
"Ships unload their ballast water from all over the world, and with it all kinds of exotic, invasive species, from viruses and bacteria to the zebra mussel," says Hand, a professor in the civil and environmental engineering department.
Hand is studying an easy, inexpensive way to kill VHS in ballast water using ordinary household bleach. It takes about five fifty-five-gallon drums, to disinfect the ten million gallons of ballast a big freighter might carry. A single barrel would work for most commercial vessels. If all boats passing north into Lake Superior were required to treat their ballast, you just might quarantine VHS.
Chlorine bleach, known to chemists as sodium hypochlorite, also kills many other microorganisms, potentially halting the spread of additional new species that could wreak havoc in the Great Lakes ecosystem. After it does its work, the bleach water can be neutralized by a number of chemicals, including vitamin C, before being discharged into the lake.
As simple, cheap, safe, and effective as this method is, it's not being used to stop VHS.
"That's because the federal ballast-water regulations only affect saltwater vessels," Hand explains. "Not only do we need to prevent the salties from bringing in new viruses, we also need the lake carriers from the lower Great Lakes to treat their ballast, because the VHS virus is already in Lakes Huron, Michigan, and Erie, and we don't want it in Superior.
"Federal law says all ballast water must be treated by 2015, but by that time, this fishery could be dead."
Hand is president of the Isle Royale Boaters Association and spends as much time as he can fishing for trout around the two-hundred-square mile Lake Superior island. Near the Canadian border, pristine Isle Royale is home to the nation's least visited national park, and Hand thinks those visitors who bring their own vessels should do their part to care for those cold, blue waters.
"We all need to protect the resource," he says. "There are five different species of lake trout on Isle Royale. We don't want to lose that."