WHIRLING DISEASE HITS CASITAS BAD TROUT IMPORTED FROM IDAHO.

Byline: Bill Becher Special to the Daily News

California Department of Fish and Game scientists have determined that some of the trout from a private fish hatchery in Idaho and stocked in Lake Casitas this winter were infected with whirling disease.

Fish from the same hatchery were also planted in other Southern California lakes including Lake Skinner near Temecula and Apollo Park Lake in Lancaster.

Even though the hatchery is tested by the Idaho Department of Fish and Game for whirling disease, the California DFG spot checks shipments of trout into California. That is how the infected fish planted in the lake near Ojai were discovered.

Whirling disease, so named because some affected fish swim in circles, is caused by a parasite that attacks the skeletal and nervous systems of young trout and salmon. The parasite has been found in California, Colorado, Montana, Idaho, Oregon and Utah. The disease is not harmful to humans or other species of fish, even if infected trout are eaten.

In Colorado and Montana the disease has caused massive declines in trout populations, as it wiped out 90 percent of newly-spawned wild trout in some rivers like the Madison. But in California, which has had whirling disease at least since 1965 when it was discovered near Monterey, it is hard to see any ill effects in trout. Scientists don't know why California trout are spared, but suspect that the faster-moving water in California might reduce the number of tubafex worms which serve as an intermediate host for the whirling disease parasites.

Despite this, California DFG aggressively monitors trout plantings, the most common cause of the spread of the disease. Bill Cox, a fish pathologist with the DFG, is particularly concerned about possible impacts of whirling disease on endangered Southern California steelhead trout.

``If young steelhead become infected they are easy prey for other fish,'' Cox said. ``Populations that are hanging on the brink of extinction don't need another thing that makes it easy for them to die.''

Cox said he plans on placing cages with young trout in Lake Casitas and Lake Skinner. Like canaries in a mine, if the young trout become infected it is a sign that the disease has taken hold in the lakes. If that happens, it is possible that trout plantings in affected lakes might have to be suspended for several years until the disease dies out.

Jim Edmondson of CalTrout, said, ``Accidents happen, and this is one of the risks when you plant trout, especially from out of state.'' He adds that the danger to steelhead in the Ventura River is remote, unless Lake Casitas fills and overflows, which is unlikely at this time.

``Hopefully all of the fish will be quickly caught and eaten,'' said Edmondson.

Casitas, which normally spends about $33,000 a year on the trout plantings, has suspended further stocking until the whirling disease situation is better understood. Brian Roney, recreation manager at the popular lake, said that the lake management is exploring an option to spend some of the money on planting catfish, bass or pan fish in place of trout.

Cox suggests that anglers carefully wash boots and waders and leave them in the sun to dry so UV rays can kill parasites. When cleaning fish, never discard guts in waterways or down a garbage disposal, as this can spread whirling disease. Fish entrails should go in dry landfills.