Biologists discover giant oysters in San Francisco Bay

(Odd that this is not in the San Francisco media...which is where this one showed up last year, about acres of tiny Asian oysters blanketing the San Pablo Bay in the north of San Francisco Bay.)

LA Daily News:

Biologists discover giant oysters in bay
Associated Press

FREMONT - Biologists have discovered giant invasive oysters that could threaten efforts to restore native oyster species in San Francisco Bay.

Government staffers and volunteers removed 256 of the exotic mollusks last week after searching the mudflats between the Dumbarton Bridge and the San Leandro Marina, biologists said.

Scientists have not identified the species, which grow up to 9 inches long and in a variety of shapes. They don't know how the exotic oysters got here or how they could affect the bay if their population expands.

Biologists are concerned the monster oysters could take over the best habitat and form reefs unsuitable for local fish and invertebrates. They could also threaten the bay's native Olympia oyster, Ostrea conchaphila, which usually grow no more than 2 inches long.

'We're really concerned about these nonnative oysters out-competing the native oysters,' said Abe Doherty at the California State Coastal Conservancy.

A big empty shell of an exotic oyster first turned up more than two years ago near the eastern end of the Dumbarton Bridge."