Biologists Fear Mystery Illness in Abalone Is Spreading : Fishing: Scientists suspect that it is the same ailment that has decimated one type of the mollusk. The experts are accused of using scare tactics.

Still puzzled by a mysterious plague that has nearly wiped out one type of abalone in the Channel Islands, state and federal wildlife experts now fear that the ailment may be spreading to other varieties of the marine mollusk--a scenario that could jeopardize commercial abalone fishing in California.

Marine biologists at Channel Islands National Park and the California Department of Fish and Game say they suspect that withering syndrome, an ailment of unknown origin that has decimated the population of black abalone in Southern California waters, is beginning to appear in red abalone.

But the theory has provoked an angry reaction from local commercial abalone divers, who charge that the scientists are crying wolf. They insist that the red abalone population on which they depend for their livelihood is healthier than it has been in years.

The future of California’s $2.8-million-a-year commercial abalone fishery may depend upon which side is right.

Scientists as yet have no proof that the syndrome has spread. But a recent surge in reports of the ailment in Channel Islands red abalone is cause for alarm, said marine biologist Pete Haaker of the Department of Fish and Game in Long Beach.

Signs of withering syndrome have also been reported in the less common pink and green varieties, Haaker said.

“We’ve been receiving reports from divers that they’ve been finding areas with lots of fresh shells, which is an indication of unusual mortality,” Haaker said. “When the public starts letting us know that there’s a problem, that’s a pretty good indication that we do indeed have a problem.”

Long valued for its tasty meat and the mother-of-pearl interior of its shell, the California abalone is already scarce.

The Channel Islands black abalone population--once the most widely harvested of the five local species--has fallen by more than 90% since withering syndrome first appeared in 1985. Decades of massive harvesting by commercial divers, exposure to man-made pollution, and an increase in predators such as sea otters have taken a severe toll on the pink, green and white varieties.

Although the red abalone population has also declined over the years, it is the only type still present in large enough numbers to support a commercial fishery. Red abalone accounted for 87% of the 519,373 pounds of abalone caught in California in 1992, according to Fish and Game statistics.

“It really concerns us because the red is the healthiest abalone fishery we have left in California,” said Haaker, who has been tracking the syndrome for eight years. “If it does the same thing in the reds that it did in the blacks, we won’t have any abalone left in Southern California.”

But some local fishermen dismiss that concern as unfounded and politically motivated.

“If they say that withering foot disease is in the reds, they’re lying,” said commercial diver Mark Rosatti, who has been catching abalone for 25 years. “We know what’s going on down there, whereas those guys are just guessing.”

Rosatti, who dives the Channel Islands from his base at Ventura Harbor, accused environmental “daisy-sniffers” of trying to use scare tactics to prohibit divers from working the islands out of a desire to “make Southern California into their own playground.”

A clearer picture may soon be at hand. In October, the Department of Fish and Game collected a number of weakened red abalone from waters off San Miguel Island, the prime hunting ground for commercial divers. A fish pathologist at the Fish and Game Disease Laboratory in Rancho Cordova, near Sacramento, is examining the mollusks for symptoms of the deadly ailment.

Commercial fisherman John Colgate, president of the California Abalone Assn., a divers organization in Santa Barbara, said it is irresponsible of scientists to raise the issue before there is definite proof that the syndrome has spread.

“They don’t even know what the disease is,” Colgate said. “I don’t know, they don’t know, nobody knows. Anything they say right now is pure conjecture.”

Colgate said he fears that the resulting publicity might lead consumers to falsely believe that the mollusk is unsafe to eat, which could drive down the price that about 125 commercial divers in California get for red abalone at market.

Divers now sell reds for about $32 a piece to seafood processors, who then export most of the catch to Japan and Hong Kong, where gourmet restaurants reportedly charge as much as $400 for a single abalone dinner.

Scientists and fishermen alike are frustrated by the fact that eight years after the first dead and dying black abalone were discovered on the south side of Santa Cruz Island, the cause of withering syndrome still has experts stumped.

Researchers do know that withering syndrome attacks an abalone’s foot--the fleshy part outside the shell--causing the mollusk to weaken and die within a matter of weeks.

But the presence of a shrunken foot alone does not necessarily mean that an abalone has the ailment, said Gary Davis, a marine biologist with the National Park Service at the Channel Islands.

Abalone tend to weaken and shrivel up no matter how they die, whether the cause is starvation, pollution or the puzzling syndrome, he said.

“It’s like saying that a human has a fever,” Davis said. “Well, what do they have that’s causing the fever?”

Early theories of the source of withering syndrome ranged from increased ocean pollution to the severe El Nino conditions of the early 1980s, which warmed ocean waters and destroyed some of the kelp beds on which abalone feed. But a UC Santa Barbara study published in June discounted those explanations and concluded that an infectious disease was the most likely culprit.

“That’s the good news,” said Armand Kuris, the marine biologist who co-authored the study. “The bad news is that we don’t yet have a causative agent identified.”

A Department of Fish and Game pathologist who is examining the red abalone has been trying to identify that agent since 1988. Carolyn Friedman has been looking at tissue and blood samples of black abalone for evidence of either a virus or bacteria, but so far has had no success in isolating either as the source of withering syndrome.

“It’s still a mystery,” Friedman said.

The decline in abalone populations in general poses an additional problem for scientists attempting to determine whether the syndrome has spread.

When withering syndrome hit the blacks, Kuris said, it was impossible to miss the fact that something strange was going on: The black abalone population was so large that the Channel Islands tide pools were filled with the dying animals.

But Kuris said that since red, pink and green abalones aren’t nearly as abundant as the blacks were, withering syndrome could be attacking them without scientists--or fishermen--knowing it.

“How could you tell if a condor population was suffering from mass mortality if you only have five condors in the population?” Kuris said. “Other abalones are so overfished that the signs of a massive mortality are hard to pick up.”

Haaker cautioned that even if the appearance of withering syndrome in red abalone is confirmed, it doesn’t necessarily mean that it would spread to the entire population.

The Department of Fish and Game is planning additional studies to see if the densities of red abalone in the Channel Islands are showing signs of abnormal decline, he said.

Haaker said that if it turns out that the mysterious syndrome has spread to the red abalone, the state’s options for dealing with it are limited.

On Aug. 1 the state was finally forced to ban the taking of black abalone from California waters for at least 1 1/2 years in an attempt to preserve the few that are resistant to the syndrome.

“If we start seeing real serious die-offs (in the reds), then I suspect we’re going to have to do the same thing,” Haaker said. “It would be tough, because fishermen aren’t going to like it. But if we don’t protect the resource, we’re never going to have a fishery.”

That prospect frightens commercial abalone fishermen.

“It would obviously be the death of the fishery,” diver Jim Marshall of Santa Barbara said. “We’d wind up with a total ban. That would be the worst possible thing.”