March 10, 2012
Sharks More Prevalent In Protected Areas, Study Claims
Using data collected from over 200 baited remote underwater video (BRUV) cameras, scientists have discovered that Caribbean reef sharks are more abundant in marine reserves than in areas where fishing is allowed.
The BRUV cameras, affectionately dubbed "chum cams," were placed both inside and outside aquatic reserve areas on the Mesoamerican Barrier Reef in the Caribbean Sea by researchers from the Stony Brook University Institute for Ocean Conservation Science.
Their goal was to test a hypothesis that claimed that "carcharhinid shark species, which include requiem and whaler sharks, are more abundant inside no-take marine reserves where fishing for sharks and their prey is prohibited," the Institute said in a Thursday press release.
In order to test their hypothesis, they used the BRUV cameras in order to record reef shark numbers, "combined these results with acoustic monitoring to measure their site fidelity (remaining within the same local area) in Glover's Reef Marine Reserve, Caye Caulker Marine Reserve, and two reefs where fishing is allowed, all located in Belize," they added. These observations lasted from 2005 through 2010.
According to an OurAmazingPlanet report published on MSNBC.com, the sharks would be attracted to the cameras by the smell of the chum, swimming towards them and allowing the Stony Brook University scientists to observe, count, record and compare the shark populations in all four locations. They observed that sharks were caught on film almost four times as often at areas where fishing was off-limits.
A total of 29% of all BRUV cameras at the two marine reserves recorded at least one reef shark during their deployment, while only 8% of those placed in a free-fishing area videotaped one of the "near-threatened" creatures, Juliet Eilperin of the Washington Post said. The findings were published online Thursday in the journal PLoS One.
Eilperin notes that fishing is completely banned at Caye Caulker and limited in Glover's Reef, where longline and gill net fishing is prohibited but other types of fishing is allowed in select locations. Furthermore, the researchers admitted to the Post that, while the use of the "chum cams" introduced bias into the survey by attracting the sharks to the cameras, they assert that the bias was identical at each of the four locations.
"Although we know that relatively sedentary reef fish and lobsters benefit from marine reserves, this study now presents visual proof that large, active sharks are also dramatically more abundant inside these protected areas, too," Mark Bond, lead author of the study and a doctoral student at the university, said in a statement.
"Nearly four times as many chum cam deployments in the marine reserves recorded reef sharks than on similar fished reefs," he added. "These areas provide the sharks and other coral reef species a respite from fishing, which means decreased fishing mortality for the sharks and more prey for them to eat."
Image Caption: Lead author of the study, Mark Bond, of the Institute for Ocean Conservation Science, positions one of the baited remote underwater video (BRUV) cameras, nicknamed “chum cams,” down current at Glover´s Reef Marine Reserve. Photo credit: : Institute for Ocean Conservation Science
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