These Fish Evolved to Live in Extremely Toxic Water

Killifish in some highly polluted Eastern rivers have evolved to survive levels of toxins up to 8,000 times the lethal dose.

Minnow-like Atlantic killifish spend their entire lives swimming in a toxic stew of chemicals in some of the United States’ most polluted waters. Now scientists have figured out why they are not just surviving, but thriving.

In four severely polluted East Coast estuaries, these little striped fish have evolved with genetic mutations that leave them tolerant of normally lethal doses of industrial pollution, according to a study led by University of California, Davis researchers to be published Friday in the journal Science.

Experts say this discovery may hold clues for better understanding how chemical pollutants affect people and animals.

“A big question has been: how quickly or readily do populations adapt in highly contaminated areas? This study really gets at that question,” says

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