Fast-growing kelp invades San Francisco Bay.The seaweed known as wakame by Japanese food lovers and used in miso soup

"Ah Miso Soup my favorite !"

SAN FRANCISCO A fast-growing kelp from the Far East has spread along the California coast from Los Angeles to San Francisco Bay, worrying marine scientists and outpacing eradication efforts.

In May, scientists for the first time found the invasive seaweed called Undaria pinnatifida clinging to docks at a yacht harbor in San Francisco Bay, fouling boat hulls and pier pilings.

"I was walking in San Francisco Marina, and that's when I saw the kelp attached to a boat," said Chela Zabin, a biologist at the Smithsonian Environmental Research Center in Tiburon, Calif.

"It was 6-foot long, and there is nothing here in the bay that gets to that size," Zabin said. "I didn't want to believe what it was, it's depressing."

Before Zabin's discovery, ocean scientists believed the northward spread of the invasive kelp had been stopped at Monterey Bay. But last year, federal funding used to buy equipment for volunteer divers dried up, reducing the number of people working on eradication.

The seaweed known as wakame by Japanese food lovers and used in miso soup was first discovered in Los Angeles Harbor in 2000.

A year later, the kelp, which can grow an inch a day as it creates dense underwater forests, showed up at Catalina Island, off the Los Angeles coastline, and Monterey Bay.