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