Repeating Islands

National Geographic reports on a new study that argues that “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.” The new research is based on an analysis of a public database of fish sightings by trained volunteer scuba divers, which provides a fairly comprehensive picture of the decline in large Caribbean predators. The problem is particularly serious in the most densely populated Caribbean countries, where too-intense fishing has wiped entire reefs clean of large predators. The absence of large predators has sent coral reefs into tailspins. “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.

Stallings based the study on the analysis of more than 38,000 surveys spanning a 15-year period in the Reef Environmental Education Foundation’s online database, focusing on 20 predator species. The findings, published in the journal PLoS ONE, revealed the drastically reduced populations of large groupers, snappers, and sharks. The Nassau grouper, once abundant throughout the Caribbean, has been so heavily fished it is listed as endangered by the International Union for Conservation of Nature. As smaller fish move in to take their place we can expect “unanticipated changes in the ecosystem” that can open the way to invasive creatures like the Pacific lionfish, a recent arrival to the Caribbean due to aquarium releases.

The situation calls for aggressive efforts at conservation of the large fish, but, as Mullings argues, “most Caribbean countries do not have strong fisheries management programs that emphasize conserving big fish.” The Nature Conservancy has begun a fisher-exchange program that brings fishers from various regions in the Caribbean together to learn about preservation.

For more go to http://news.nationalgeographic.com/news/2009/05/090508-caribbean-predators-disappear.html

Image credit: “Photographer and Goliath Grouper, Epinephelus itajara,” by Michael Patrick ONeill/MSNBC Nature’s Best Photography 2008.