Saving fish in troubled waters

A Michigan Technological University professor has developed a new water treatment that could help keep a deadly fish disease out of Lake Superior in North America.

Prof David Hand of the civil and environmental engineering department at the university has devised a simple way to treat ballast water in vessels ranging from pleasure craft to ore boats.

His method is designed to kill the virus that causes viral hemorrhagic septicemia (VHS), an often-fatal disease that has been attacking fish populations in the lower Great Lakes.

Prof Hand's treatment is simple. The ballast water is disinfected with sodium hypochlorite - ordinary household bleach. Then it is treated with ascorbic acid, or vitamin C, which neutralises the bleach before the water is released into the lake.

With good initial results, Prof Hand has tested his method on the Ranger III, a National Park Service vessel that shuttles visitors and staff between the mainland and Isle Royale National Park.