By spending hours in the water making detailed observations of bumphead parrotfish eating habits, the team is trying to piece together what a reef without these heavy eaters would look like.
Sharks are also important for healthy coral reef ecosystems. For decades, conservationists have tried to protect reef sharks by setting aside reserves like Palmyra that provide a safe space to grow and reproduce. But sharks tagged at Palmyra have been caught by fishermen at reefs hundreds of miles away, McCauley said.
Shark tissue also contains unique ratios of carbon and nitrogen isotopes that identify its reef of origin. By sampling shark tissue, Stanford marine scientist Rob Dunbar confirmed that these top predators have been straying far from their home reefs.
"At Palmyra, we're finding that some sharks don't stay at home like we thought, so managers can't protect them outside the sanctuary borders," McCauley said. "It seems that effective management strategies for gray reef sharks and other similarly wide-ranging species will need to be thought out at much larger scales."
Shark meat is an important part of local diets, and shark fins garner large sums of money from traders who re-sell them to soup manufacturers. In 2009, Stanford anthropologists Bill Durham and Doug Bird, along with graduate student Eleanor Power, monitored the activities of Tabuaeran fishermen on daily forays for reef animals and conducted interviews with atoll elders on the history of local fishing. The results of these surveys will be used to assess fishing patterns and provide information to Tabuaeran leaders looking to achieve sustainable harvests.
Because the livelihoods of so many Tabuaerans depend on healthy fisheries, locals are eager to preserve fish numbers, McCauley said. "Those who depend most on the environment can and should be its be
|Contact: Mark Shwartz|