Menacing Bambis : Intruder Plants, Animals Pose Bay Area Threat

SAN FRANCISCO —  Renegade “Johnny Appleseeds” are threatening to upset the Bay Area ecosystem--and economy--by introducing non-native plants and animals that can crowd out, beat up and kill native species.

While one mysterious character known only as Klaus has been irritating city gardeners by planting weeds in Golden Gate Park, persons unknown have admitted to seeding ocean fishing grounds with a tasty but pugnacious East Coast crab.

The results, scientists say, can range from uglier parks to decimated crab-breeding grounds.

“It’s a real serious problem,” said Dusty Chivers, a zoologist with the California Academy of Sciences. “It’s the Bambi syndrome. People think they are doing this cute, little (non-native) animal a favor by releasing it, but they don’t know how many other (native) animals they may be dooming.”

The most serious problem could be several hundred feisty Atlantic blue crabs.

Two of these particularly aggressive creatures have been found in waters off San Francisco recently, and scientists suspect that hundreds more may be roaming the bay--with the potential to wipe out native Dungeness crabs, causing a “major restructuring” of local fish life.

“If they do establish themselves in the bay, all hell would break loose,” said Chivers, who has been studying the two foreign crabs. “They can easily out-compete shrimp and other crustaceans for food. . . . I think it probably would mark the end of San Francisco Bay as a nursery for the Dungeness.”

To the relief of scientists and fishermen, young blue crabs, unlike their parents, cannot survive long in the chilly waters off San Francisco. But with indicators hinting at a return of El Nino--a meteorological phenomenon that pushed unusually warm waters to the California coast in the early 1980s--the fear of a permanent blue-crab colony persists. Their average life span is seven to 10 years.

Powder Keg

“We could be sitting on a powder keg that could go off in a day or a week--or never,” Chivers said.

The first blue crab found, a male measuring eight inches across, was pulled last month from waters off Princeton-by-the-Sea, a small town 15 miles south of here. The second, a smaller female, turned up earlier this week off Fort Point at the southern end of the Golden Gate.

Both are now at the academy’s Steinhart Aquarium, impressing scientists with their ferocity. When the first one found was given shrimp to eat, it killed the shrimp for sport.

“It looked like the ‘Sands of Iwo Jima,’ what with all the carnage,” Chivers said, referring to an old movie about the bloody World War II battleground.

Publicity given the two blue crabs has prompted several people to confess--anonymously--that they had either dumped blue crabs into the sea themselves or seen others do it.

One man, for example, said he recently dumped 40 blue crabs into a creek that empties into the sea near Princeton. Another said he saw someone dump two boxes of 200 to 300 crabs each into the ocean off Princeton three years ago.

Scientists suspect that the dumping may have been an ill-advised--and illegal--attempt to introduce the crabs as a replacement for the slowly dwindling local supply of the less-hardy Dungeness crabs.

“It’s the equivalent of aquatic Johnny Appleseeds . . . “ Chivers said. “They don’t understand they can upset the ecological balance or introduce a terrible new disease. They don’t see the potential for . . . horrendous economic havoc.”

Weed Spreader

Golden Gate Park gardeners have a similar picture of their less serious but no less nettlesome nemesis. “He is the Johnny Appleseed of the invasive weed world,” park employee Kevin Shea told a local reporter.

The weed planter was confronted by a park worker one day as he was planting the daisy-like South African capeweeds. He identified himself as Klaus before fleeing. He also is suspected of dosing some of the park’s 11 lakes with water hyacinths, which choke out popular water lilies.

“It has been a constant battle,” said Jim Rogers, assistant park superintendent. “I have never caught the man. I don’t know if I could restrain my fingers from around his neck if I did.”