Transoceanic transport mechanisms: introduction of the Chinese mitten crab, Eriocheir sinensis, to California

Of 10 mechanisms available for the long-distance transport of crabs, evidence from the history of the mitten crab's global spread, data on ship traffic, the sampling of ballast water fauna, and recent patterns of introductions support the hypothesis of introduction via ballast water. Alternatively, the pattern of governmental interception of mitten crabs, their high market value, and continuing pressure to lift the import ban suggest that introduction may have been achieved via an intentional, private-party inoculation to establish a food resource. For either mechanism, the immediate source is more likely Asia than Europe.