The deaths of hundreds of carp that are littering the shores of Lake Mendocino remained a mystery on Wednesday but some clues could emerge as soon as Thursday.

"We're doing a lot of testing," said Ryan McClymont, a spokesman for the U.S. Army Corps of Engineers, which manages Lake Mendocino.

Water and fish samples have been sent to state laboratories, he said.

The results of the water samples sent to the Department of Fish and Wildlife and the fish samples sent to UC Davis are expected sometime Thursday, McClymont said.

The Davis laboratory is testing for koi herpes virus, he said. Koi is a domesticated, ornamental carp, also related to goldfish. All three fish are susceptible to the virus, which is not believed to be harmful to other fish or humans.

The koi herpes virus was first detected in the United States in 1998 and outbreaks have since been identified worldwide, according to the UC Davis Veterinary Medical Teaching Hospital's website.

The disease is suspected of killing thousands of carp in Lake Ming near Bakersfield in 2010, Lake Kaweah in Tulare County in 2009, and Clear Lake in 2008, according to news reports.

The Ontario, Canada Ministry of Natural Resources reported dead and dying carp in 29 bodies of water in central Ontario in 2007 and 2008.

Officials suspect infections can be triggered by people dumping their unwanted koi or goldfish into lakes.

The virus does not affect humans and the fish are safe to eat and handle, according to wildlife officials.

If the virus is to blame for the Lake Mendocino carp deaths, it will be allowed to run its course, McClymont said.

"There's no action we can take to stop it or prevent it," he said.

If the deaths, first reported Sunday, are not due to the herpes virus, it could be another month before the results of other tests are available, McClymont said.

As for the fish carcasses, their disposal will be left to the elements and other animals unless they become a nuisance, he said.

"We'll see what nature can do first," McClymont said.

You can reach Staff Writer Glenda Anderson at 462-6473 or