Great Lakes fish virus may threaten U.S. aquaculture

The Fish Site
by The Fish Site
24 April 2007, at 1:00am

CHICAGO - A virus in the U.S. Great Lakes, that has killed tens of thousands of fish in recent years, is spreading and poses a threat to inland fish farming, a U.S. Agriculture Department official said on Monday.

The pathogen, viral hemorrhagic septicemia, or VHS, causes internal bleeding in fish. It does not harm humans, even if they eat infected fish.

The federal agency issued an emergency order in October to limit movement of live fish caught in the eight states bordering the Great Lakes and two Canadian provinces.

"We're concerned that this virus could get out of the Great Lakes and affect other populations," said Jill Roland, a fish pathologist and assistant director for aquaculture for USDA in Riverdale, Maryland, said.

"The virus could potentially affect the catfish industry and as the species make up the largest sector of the $1 billion U.S. aquaculture industry, accounting for $462 million in sales, according to a 2005 USDA aquaculture census, this is a significant problem.

The public first began hearing about the virus in May 2006 after fish began to die in Lake Ontario, Lake Erie and the upper St. Lawrence River.

There is little the government can do to prevent the spread of the disease, other than limiting human movement of fish that may be infected.

Fish caught in the Great Lakes may be used as bait in other parts of the country, with extra fish dumped into the water. Commercial farms sometimes get their breeding stock from wild fish.

However, fish migrate naturally and the Great Lakes does connect with the Mississippi River, a major waterway that runs to the Gulf of Mexico.

Source: Scientific American