Attack of the Alien Invaders, National Geographic Magazine: Scientists Study Aquatic Exotics

A large red orangism floats on computer screen with scientists working in a white labratory.

Colorful aquatic worms swim across the computer screen as scientists and researchers study samples in a lab after collecting water in San Francisco Bay. According to Dr. Andrew Cohen, hundreds of nonnative species have had a profound impact on the ecology of the Bay making it the world’s most invasive species-impacted ecosystem.

Ballast water dumped by ships moving from port to port spreads bacterial pathogens as evidenced by a cholera outbreak in Peru, which was the first outbreak of the disease in the Western Hemisphere in a century.

One serious invading problem introduced into the Bay waters are Chinese Mitten Crabs–medium-sized burrowing crabs named for their dark furry claws. They cause severe damage to embankments, erosion and clogged drainage systems.

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