A total of 138 non-indigenous fish species have been identified in the U.S. Most have set up housekeeping in warm climates such as Florida (50), California (56) and Hawaii (33). Forty-four native species of fishes are threatened or endangered by non-indigenous fish, while an additional 27 species are negatively affected by introductions. The Pimentel group estimates that the annual economic cost is $1 billion.

GRASS CARP (Ctenopharyngodon idella) has altered the ecology of aquatic ecosystems by reducing natural vegetation. The common carp (Cyprinus carpio) reduces water quality by increasing turbidity.

Data: Excerpted from Environmental and Economic Costs Associated with Non-indigenous Species in the United States

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