Pacific Reef Sharks Vanishing Near Populated Islands

As many as 90 percent of reef sharks have disappeared from reefs near populated islands, a new study finds.

The research is the first to provide a large-scale estimate of reef sharks in the Pacific, a group of species that includes the gray reef shark, the whitetip reef shark and the tawny nurse shark.

"We estimate that reef shark numbers have dropped substantially around populated islands, generally by more than 90 percent compared to those at the most untouched reefs," said study leader Marc Nadon, a doctoral candidate at the University of Miami's Rosenstiel School of Marine & Atmospheric Science. "In short, people and sharks don't mix."

Nadon and his colleagues pulled shark sighting data from more than 1,607 dives at 46 reefs in the central-western Pacific, which included reefs near the Hawaiian islands and American Samoa as well as extremely isolated reefs nearly devoid of human influence. Though eight species of shark were seen on the dives, the researchers excluded sharks, such as hammerheads, that aren't dependent on reefs. That left them with five shark species to tally: gray reef sharks, blacktip reef sharks, whitetip reef sharks, Galapagos sharks and tawny nurse sharks. 

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