Cargo Vessel Ballast Waters as a Vector for the Spread of Toxic Phytoplankton Species to New Zealand

Toxic phytoplankton inadvertently introduced to New Zealand's marine waters have harmed the aquaculture industry, commercial fisheries, the environment, and human health. Records of toxic outbreaks and phytoplankton blooms in New Zealand suggest that cargo vessel ballast water can act as a vehicle for the spread of dinoflagellates. Five stages in this transfer are identified: intake of plankton into ballast water at port of origin, survival during transport, ballast tank plankton viability on arrival, release and survival, and continued reproduction. Regulations appropriate for each stage are proposed.