LOS ANGELES (REUTERS) - Stephanie Mutz makes a living plucking sea urchins from the Santa Barbara coast and selling the prickly treasure to upscale restaurants in Southern California.

Now, she needs new hunting grounds.

The coast, thought to be one of the world's best places for harvesting sea urchins, suffered its worst oil spill in 46 years this week, forcing authorities to ban fishing in an area 37km long by 11km wide.

"That was one of my predominant fishing spots, so I just have to think of a Plan B," said Mutz, who supplies restaurants from Santa Barbara to Orange County, including the Michelin-starred Providence in Los Angeles.

It is unclear the extent of damage to the seafood industry from the leak of up to 2,500 barrels of crude oil from a ruptured pipeline into the Pacific Ocean.

But Tuesday's spill raised concerns about the vulnerability of the marine life, a prized source for chefs keen to serve local catch.

"You don't want to see anything happen to any part of the California coastline," said Michael Cimarusti, chef-owner of Providence, considered one of the country's best seafood restaurants. "It's an important watershed up there."

At sister restaurant Connie and Ted's, which features Santa Barbara seafood, chef Sam Baxter said the fishing season, which began in May, could slacken during oil clean-up. "It's hard to know how long it is going to be out there," he said.

In addition to sea urchins, often called by their Japanese name "uni", Santa Barbara supplies lobsters and crabs. The famous Santa Barbara Spot Prawns, however, are often found along other parts of the coast.

Five crab boats could not access traps laid in the area and lost some 225kg of crab each, said Brian Colgate, owner of Santa Barbara Fish Market.

On Thursday, the California Department of Fish and Wildlife expanded the fishing ban from one mile offshore to seven. If choppy waves and gusty winds carry the oil out, the no-go zone could expand.

David Lentz, chef-owner at the seafood-centric Hungry Cat in Los Angeles and Santa Barbara, worries about "super detrimental" effects for fishermen.

"I don't think it's 100 percent clear how bad it is," Lentz said. "It's really early."

Mutz wasn't taking any chances. She sent a message to chefs assuring them she would harvest far from the oil and headed to the Channel Islands, 48 km away, to get her urchins.