SYDNEY, July 29 (Xinhua) -- Mating and spawning aggregations of fish and other prey are playing a key role to conserve shark populations, Aussie researchers have found, after observing up to 900 reef sharks living in a remote part of the world.
Published in the journal Current Biology on Friday, researchers found as many as 900 reef sharks living in an untouched reef pass in a marine reserve off French Polynesia, despite the prey living there not providing enough to eat.
The study suggests instead the sharks get by from "meals on wheels," or spawning aggregations of groupers that annually migrate to the reef pass which initially drove the scientists there.
"We noticed the massive number of sharks in this channel, especially grey reef sharks, and questioned how such a large number of sharks can be maintained, and where they find their food," Macquarie University marine scientist Johann Mourier said in a statement.
Sharks have been known to target aggregated fish populations before, but the study is the first to suggest they play in integral part in feeding behaviour, having important implications for conservation.
"Implementing strong shark protection laws is unlikely to be sufficient to maintain high numbers of sharks if not jointly implemented with conservation of fish spawning aggregations," Mourier said.
If overfishing leads to a loss of those aggregations, sharks "will have no other choice than undertaking energetically costly, wider-range foraging to meet energy requirements," suggesting the natural abundance of reef sharks have been lost due to human influence.
