Zebra Mussels Invade California

From the Los Angeles Times:
The zebra mussel that has wreaked havoc in waterways around the nation has been found in California [for the first time], dismaying state and federal water officials who hoped to prevent the fast-spreading mollusk from reaching the West Coast.

State officials do not know how the mussel traveled west of the Rockies, although they suspect it may have hitched a ride on a recreational boat transported by trailer.