Environmental Impacts Caused by Exotic Species from Ballast Water

Exotic species are fundamentally altering many aquatic ecosystems. Federal agencies are particularly concerned about the impact of non-natives upon threatened and endangered native species, compounding the adverse effects of habitat loss, over-fishing, and pollution. Exotic species compete for food with native species, prey upon them, and carry parasites and diseases. Human pathogens have also been found in ballast water. Recent studies in the Chesapeake and Mobile Bays found cholera in ships' ballast water, highlighting its threat to human health.

In addition to environmental impacts, exotic species colonize on boat hulls and clog water intake pipes for power plants and drinking water treatment facilities. The costs associated with exotic species are staggering. For example, Congress has estimated that in the Great Lakes alone the exotic zebra mussel has caused in excess of $5 billion in damage over the last ten years. In Washington, the $40 million shellfish industry is alarmed by the approach of the European green crab which, first identified in San Francisco Bay in 1989, had migrated as far as Grays Harbor, WA by the summer of 1998.

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