ECOLOGY WATCH : Musseling a Way In

They’re the terror of Middle America and they’re coming west. By boat.

Not many have been spotted in California, but it may be just a matter of time before they are here in the millions if safeguards are not taken. Call it the Invasion of the Zebra Mussels, and it’s not a comedy.

The black-and-white striped mollusks, barely an inch in diameter, will pose a serious threat to the state’s elaborate water systems if they take hold. And taking hold is their specialty.

In the Great Lakes in the 1980s and along the great Midwest river systems in recent years, the zebras showed a proclivity for piling onto water intakes in huge colonies, clogging pipes and jamming machinery. So far they have resisted almost every attempt to do them in.

The zebras can be poisoned, but then fish that share their waters are poisoned too. At a Cleveland plant, a high-pressure water hose had to be used to blast the mussels from filter screens. On the Canadian side of Lake Erie, 30 tons of zebras were removed from an Ontario water plant’s intake pipe.

Scouts have been spotted at California border stations in the last two years, twice this summer. In both recent cases, they were attached to pleasure boats being trucked in from Michigan. The zebras, natives of the former Soviet Union, arrived in the Western Hemisphere in the 1980s, presumably in the bilge of a vessel entering the St. Lawrence Seaway.

California border inspectors are on the lookout, but boat owners bear a responsibility too. Check your hulls and motor housings. And no, these mussels are not edible.