Agency loosed abalone threat

State Fish and Game officals say diease has not taken
hold of red abalone population despite 1995 mistake

July 12, 2001

By PAUL ENGSTROM
THE PRESS DEMOCRAT

State Department of Fish and Game officials admitted Wednesday they accidentally contaminated wild red abalone along the North Coast with the same disease that decimated the black abalone populations of Southern California.

Officials with the department said they have been closely monitoring the health of Northern California's red abalone ever since they realized their error in 1999.

Fish and Game officials said while the disease is not now taking hold of red abalone beds along the North Coast, it does pose a significant threat.

Tainted abalone seed were introduced to wild populations off the coasts of Fort Bragg and Crescent City in 1995 during so-called outplant projects. The environmentalist-endorsed projects were conducted to learn whether depleted wild stocks of the prized catch could be buttressed with farm-raised abalone.

But in 1999, officials discovered that the farm-raised abalone stock they planted in the wild was contaminated with a bacteria called rickettsia-like procaryote, or RLP, which causes withering syndrome in certain types of abalone.

"In retrospect now, it does appear that some of those (seeds) were infected," said Robert Hulbrock, aquaculture coordinator for Fish and Game in Sacramento. He said the agency continues to sample wild abalone between Crescent City and Bodega Bay to monitor the situation.

Though not harmful to humans, the infectious disease attacks black, pink and red abalone and causes the mollusks to lose weight and eventually die of starvation.

Hulbrock said withering syndrome has not so far been seen north of San Francisco, adding that he's "cautiously optimistic" it won't any time soon.

But he acknowledged that the true extent of the threat will remain unclear until more studies are done.

The disease is best known for having decimated the black abalone populations in Southern California in the 1980s, leading to the demise of the state's commercial abalone industry.

Black abalone populations from San Diego to Cayucos had declined by as much as 99 percent by 1998. The state imposed a partial ban that year on shipments of abalone to and from Northern California hatcheries to keep the disease from spreading northward.

Abalone can host the bacteria that causes withering syndrome, yet not succumb to it.

Researchers at the department's Bodega Bay Marine Lab are studying the possibility that North Coast red abalone haven't contracted withering syndrome because coastal waters north of the Golden Gate are too cold to permit the bacteria's infection of the mollusks.

But they warn that the situation could change in the event of a water-warming climate change, such as another El Niño event.

"We know that in warmer water, this organism causes severe damage," said Dallas Weaver, president of the Aquaculture Disease Advisory Committee at the California Department of Fish and Game.

"But we don't know if it causes as much damage in the North -- if any damage to speak of -- as in Southern California."

Last month, NASA scientists predicted another El Niño could be as little as a year away.

Red abalone, which survive from the Marin County coastline north to the Oregon border, are a favorite catch for sport divers from all over the state, who have been coming to Sonoma and Mendocino counties since abalone harvesting was banned south of the Golden Gate in 1997.

Mature mollusks generate significant tourism income for North Coast communities during the state-sanctioned abalone diving season, which runs from April through November with a monthlong break in July.

But Weaver said sport divers may unwittingly contribute to the spread of RLP bacteria when they clean infected abalone and toss the waste back into the ocean where it is eaten by uninfected abalone.

The threat of withering syndrome has already put a crimp in the operations of North Coast aquaculture facilities that grow and sell the millimeters-long abalone seed to abalone farms or grow the mollusks to maturity for market.

You can reach Staff Writer Paul Engstrom at 521-5257 or e-mail pengstrom@pressdemocrat.com.

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