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Fish are seen at Cabo Pulmo National Marine park, in Baja California State, Mexico on June 22, 2010.

Located between Baja California and the Mexican mainland, the Sea of Cortez was once known for being one of the diverse seas on earth. Jacque Cousteau called it the "aquarium of the world."

A lot has changed over the years though, and not for the better. Overfishing has completely wiped out some species and severely diminished others. Erik Vance wrote about this unfortunate trend for Harper's Magazine, and joins the show.