The fix for a European pest may be its European foe

By TIM BLAIR

even times in the past year, researcher Ron Thresher has placed various Australian crabs in a tank with a European green crab. "We're zero for seven so far," says Thresher. "The European green just races over and tears them to bits."

The lab battle is played out thousands of times off Australian coasts each day. Since arriving via the hulls of cargo ships a century ago, Carcinus maenas has established itself in vast numbers near the mainland--and now in the waters off Tasmania, where Thresher, head of the government's Centre for Research into Introduced Marine Pests, leads an international team of scientists combating the crustacean. A single C. maenas eats hundreds of native shellfish each month. Says Thresher: "Where you find large populations of green crabs, you won't find native crabs at all."

Thresher's team proposes introducing another outsider: the Sacculina carcini barnacle, European nemesis of C. maenas. During its larval stage, S. carcini pierces the crab's exoskeleton, introducing cells which grow into branches, swamping the crab's organs and causing sterility.

Pending proof that S. carcini is harmless to native marine life, Thresher is hoping for government approval to release the stealth barnacle into Australian waters within two years, the first time ever a biological control would have been launched against marine pests. By then, the rapid spread of C. maenas may call for further deployments. In Oregon, where C. maenas appeared last year, Deborah Brosnan, president of the Sustainable Ecosystems Institute, is discovering that the invader enjoys Coos Bay as much as Tasmania's coast. "It wreaks havoc," she says. "It eats hundreds of species. It's the perfect predator." Perhaps only as long as S. carcini is restricted to European waters.