Sharks play a key role in regulating the health of a coral reef by eliminating predators that prey on the small fish that keep the coral healthy, according to an Australian study released recently.
Higher numbers of sharks off the country’s remote north-west coast – versus the north-east, where the Great Barrier Reef is – suggest that “sharks play a key role in regulating the health of coral reefs,” the University of Western Australia said in a statement.
Researchers from the university travelled from Cairns to Broome over four months to study the relationship between sharks and reefs.
“We have made predictions that where you have higher shark abundance, the corals are healthier,” said Jessica Meeuwig, the study’s programme leader.
Sharks keep under control the mid-sized predators that are their prey or competitors, allowing small reef fish, the real caretakers of corals, to thrive, Meeuwig said.
“Increasingly we’re seeing that in marine protected areas with healthy shark populations, the corals themselves recover faster from flooding, from bleaching – they have lower incidence of disease,” she said.
Coral reefs, home to at least one-quarter of all marine life, are changing rapidly as they struggle to cope with the combined impacts of global warming, overfishing and pollution.
Determining how sharks contribute to reef resilience is critical, Meewig said.
“We have seen a major decline in the number of sharks and fishes in the last 50 years,” she said. “The question is how do we halt and reverse the decline.”
“We need to understand the role that sharks … play in maintaining healthy ecosystem,” she said. – dpa