By JASON DEAREN, Jason Dearen, Associated Press
Writer – Sat Jul 11, 3:04 am ET
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.
Studies have concluded the kelp was likely introduced to
California by accidental transport on shipments of oysters, vessel
hulls and people who cultivated it in the region for cooking.
On Thursday, four divers spent hours at Pier 40 on San
Francisco's Fisherman's Wharf peeling pieces of kelp off of the
docks, yachts and pier pilings. But few believe the effort removed
all traces of the seaweed. Scientists will be checking monthly for
signs of further spread.
"On any invasion, the window of opportunity to successfully
eradicate that species is usually narrow," said Steve Lonhart, one
of the divers and a senior scientist with the Monterey Bay National
Marine Sanctuary.
"You want to do it as soon as it becomes established. The longer
you wait, the less chance for success," he said.
The seaweed concerns marine biologists because it can damage
fragile ocean ecosystems by choking off the sunlight needed by
native kelps. The native kelp forests provide key habitat for
otters, fish and other marine life.
The seaweed spreads by releasing millions of spores that can be
dispersed by currents in the open ocean, but in a protected marina
lighter currents could slow its reach. While it is native to Japan,
China and Korea, studies have found the kelp in the Mediterranean
Sea, the Atlantic Coast of Europe, New Zealand and Argentina.
"If it's restricted to two docks in the marinas in San Francisco
Bay, we'll have a chance," Zabin said. "If it's spread beyond those
places, it may be a lost cause."
Because of its wide range, it has been nominated as among 100 of
the world's worst invaders, according to the Global Invasive
Species Database.
Though Thursday's dive may remove the immediate threat to the
bay, Lonhart believes they are fighting a losing battle against a
persistent pest.
"In 10 years I'm guessing Undaria is going to be all over the
place. It's not a problem getting smaller in scope, it's getting
worse and worse," he said.
Scientists say the waters from Baja California to British
Columbia are the perfect temperature for Undaria to spread even
further up the Pacific Coast of the United States.
For about six years, the National Oceanic Atmospheric
Administration had organized monthly volunteer diving efforts to
yank the stubborn kelp out of Monterey harbor to help root out the
kelp.
The program helped, but it failed to stop the kelp from entering
San Francisco Bay, scientists say.
"This is not well studied enough, and we're really quite nervous
about it getting out in the ecosystem," Zabin said. "It will attach
to about anything."
That's really a cause for concern. They survive pretty well
almost anywhere.
