The big fish that prowl the Caribbean reefs—gaping groupers, sharp-toothed barracuda, and gigantic sharks—are completely gone in some places due to overfishing, a new study says.
The problem is worst in the most densely populated Caribbean countries, where fishers have wiped entire reefs clean of large predators.
In such places, smaller predators have begun to fill in niches left by the big hunters—sending coral reefs into a tailspin.
(Related: "Predator Fish Help Coral Reefs Rebound, Study Shows.")
The new research, based on a public database of fish sightings by trained volunteer scuba divers, provides one of the most comprehensive glimpses so far of the decline in large Caribbean predators.
"Healthy and intact coral reefs need large predatory fish in order to continue to provide human societies with food and with beauty," said study author Chris Stallings, a researcher at Florida State University's Coastal and Marine Laboratory.
Phillip Kramer, director of the Caribbean program for the nonprofit group the Nature Conservancy, agreed that "you can't take the large carnivores out of the system.
"It's like the deer in Yellowstone without the wolves—you'll have cascading impacts," said Kramer, who was not involved in the research.
Off Balance
Stallings studied more than 38,000 surveys over a 15-year period in the Reef Environmental Education Foundation's online database, which Stallings said is a reliable source for fish sightings.
He examined 20 predator species of varying sizes and their abundance across the region.
The findings, in the journal PLoS ONE, revealed that some species of large groupers, snappers, and sharks—such as bull sharks, tiger sharks, and blue sharks—are now gone near densely populated areas.
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