Primary Vector: Ballast Water

The mitten crab can travel great distances as a zooplankton free-floating in ships' ballast water. (Cohen and Carlton 1997) With minimal regulations in place to control the release of ballast water in ports, many aquatic nuisance species, including the mitten crab, are transported and released into waters around the world. To begin to comprehend the magnitude of possibilities for nonindigenous species to invade, Cohen and Carlton carried out a study focusing on the Chinese mitten crab that found 75 ships in a given year possibly carrying the crab, of these a grand total of 402,024 metric tons of ballast water was exchanged in San Francisco Bay. (1997) In addition, ports are usually located in somewhat brackish, estuarine waters, thus possibly being suitable for the larval crabs to continue on in their life cycle.

created 5/4/98