The commercial crab-fishing season was put on hold Friday to protect the public from a naturally occurring toxin detected in the crustacean, an unprecedented setback for California fishermen and chefs hoping to land the prized meat for the holidays.

The widely expected but disheartening move by state wildlife officials indefinitely grounds the traditional parade of boats that was scheduled to launch Nov. 15 in pursuit of Dungeness crabs between the Oregon border and Santa Barbara. Officials also closed the state’s year-round rock crab commercial fishery.

“Crab is an important part of California’s culture and economy, and I did not make this decision lightly,” said Chuck Bonham, director of the California Department of Fish and Wildife, in a prepared statement. “But doing everything we can to limit the risk to public health has to take precedence.”

Bonham’s directive follows a decision Thursday by the California Fish and Game Commission to suspend Saturday’s recreational Dungeness season opener as well as the recreational rock crab season.

The fish and wildlife agency said it will continue to monitor levels of the toxin in the crab, the result of a massive algal bloom offshore, until fishing can safely commence. Officials, though, didn’t speculate on when this might happen, and crab fishermen who have come from as far as Alaska to begin prepping their pots for an annual catch worth $60 million weren’t optimistic.

“I’m no scientist, but I think this is going to take a while,” said Larry Collins, president of the Crab Boat Owners Association and the San Francisco Community Fishing Association. “We’ve got to see some clouds and wind and rain and upwellings. Ocean conditions have to change.”

Unusually warm water along the West Coast has been blamed for nursing an algae known as pseudo-nitzschia, which is proliferating in huge swaths off much of California. The algae produces a nuerotoxin called domoic acid that accumulates in crab and other seafood and, if consumed in substantial quantities by humans, can cause memory loss, tremors and even death.

State health officials said this week they aren’t aware of anyone who has been sickened by infected crab. But marine life, including sea lions, seals and whales have been reported to have suffered seizures believed to be the result of ingesting the toxin.

“Absolutely it’s going to cost us some money, but the No. 1 priority is to provide safe, healthy beautiful crabs,” said Collins. “Sometimes Mother Nature bats first and last. It’s up to her.”

The delay of the season means restaurants that serve crab will have to import the meaty wintertime staple from elsewhere.

“Really we’ve never experienced anything like this before,” said Dante Serafini, the owner of the Old Clam House, a longtime fixture on Bayshore Boulevard in San Francisco that is known for its crab cioppino. “Yeah sure, it will affect my business. I don’t know what we’ll do, but we have to substitute something.”

Serafini said he wants people to know that the crab being sold right now, much of it coming from colder waters in the Pacific Northwest, is perfectly edible.

“If you want your crab, now is the best time to eat it in view of this crisis,” he said. “It’s not the freshest, but it’s still good.”

Kurtis Alexander and Peter Fimrite are San Francisco Chronicle staff writers. E-mail: kalexander@sfchronicle.com, pfimrite@sfchronicle.com Twitter: @kurtisalexander, @pfimrite