What has Ballast Water Introduced into California?
Ballast water discharges have released Japanese gobies, New Zealand sea slugs, Black Sea jellyfish, dozens of Asian zooplankton species, possibly the Chinese mitten crab, and scores of other organisms into the San Francisco Estuary. Other species have been introduced into Los Angeles/Long Beach and San Diego harbors. The amount of foreign ballast water arriving at these ports will increase sharply with port expansions and with the projected rapid growth in international markets and trade. Many exotics that first arrive at these major shipping ports then spread or are reintroduced to other sites along the coast. The asian clam Potamocorbula was introduced by ballast water discharges into San Francisco Bay in 1986. Within a year it was the most abundant clam in the northern part of the system, filtering the entire water column twice a day, destroying phytoplankton blooms and disrupting the food webs that support fish in the Estuary. It has now become evident that Potamocorbula also acts
