A joint research project by the University of Queensland, James Cook University and University of Tasmania found that existing marine reserves need to be much larger to be effective against the overfishing of sharks species.
The study, funded by the Shark Conservation Fund and published in the journal Current Biology, estimated that no-take reserves along coral reefs that extend between 10 and 50 kilometers may reverse the decline in the world’s coral reef shark populations caused by overfishing.
“Existing protected areas on coral reefs would need to be enforced as strict no-take reserves and be up to five times larger to effectively conserve reef sharks,” University of Queensland researcher Dr. Ross Dwyer said. “Those in the Atlantic where reef sharks are generally less abundant would need to be on average 2.6 times larger than those in the Indian and Pacific Oceans.”
The researchers looked at tracking data for five species of sharks found on coral reefs in the Indian, Pacific and Atlantic oceans as well as video survey data from an additional 36 countries.
“Our results show that marine parks for reef sharks need to be large. But if reserves extend along 15 kilometers of coral reef, then fishing mortality can be reduced by fifty percent,” Dr. Nils Krueck from the University of Tasmania said.
Species such as grey reef sharks have experienced severe population declines across parts of their distribution, largely due to their low fecundity, late age at sexual maturity, and high susceptibility to fishing pressure. They are listed as Near Threatened in the International Union for Conservation of Nature’s (IUCN) Red List of Threatened Species.
“Finding ways to rebuild their populations is critical to ensuring our oceans remain healthy,” Colin Simpfendorfer from James Cook University said. “This project is providing options for managers of coral reefs to address declines in shark populations which scientists know have occurred in many areas.”