What is the extent of the problem?
Over 234 non-native plant and animal species have already been established in the San Francisco Bay/Delta. Up to 97 percent of all organisms and 99 percent of all the biomass in San Francisco Bay are foreign species. For examples, Chinese mitten crabs threaten to clog water pumps and disrupt water supply. European green crab preys on Dungeness crabs and Pacific oysters, threatening local shellfish and aquaculture industries.