A container ship passes under the Golden Gate Bridge in San Francisco Bay, THE most <br /> impacted ecosystem in the world. Ballast water moved from port to port also spreads human pathogens--there is evidence that cholera bacteria that returned to Peru in 199 was the first outbreak in the Western Hemisphere in a century. It was brought by ships from Asia in ballast water. <br /> Since 1970, on average, one new species has been introduced every 24 weeks into the bay <br /> and surrounding estuaries. According to Dr. Andrew Cohen of the San Francisco Bay Estuary Institute, the bay has over 240 invasive species. Dr Cohen sounded the alarm about the increasing impact of foreign species beginning with the Chinese mitten crab and European green crab. The mitten crab is responsible for horrific erosion problems while the green crab out competes the native Dungeness crab for resources. <br /> Most of the fish found in the Bay's delta are non-native. All of these non-indigenous species <br /> have had a profound impact on the ecology of San Francisco Bay.
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