Where Australia's sharks go to stay looking sharp

A pampering session at the beauty salon always works wonders for morale – not just for humans, but also for sharks and manta ray fish. Australian scientists have discovered that these large marine creatures regularly congregate at certain spots on the Great Barrier Reef to be groomed by smaller fish.

The sharks and rays park themselves in reef "salons", where fish that would normally be their prey swarm all over them, removing dead and diseased tissue, mucus, scales and ectoparasites, according to a research team from Queensland's James Cook University.

The larger creatures could be forgiven for snacking on the odd fish while kicking back and relaxing, but that never happens, say the scientists, who set up cameras at several sites on the Great Barrier Reef and also at Osprey Reef, just off Cairns in Queensland.

On the contrary, the smaller fish derive nutrition from the detritus that they remove from their "clients". Over five months the team, from the university's School of Marine and Tropical Biology, observed sharks and rays gathering frequently for a "clean, wax and polish".

The grooming sessions sometimes lasted several hours, with the smaller fish carrying out cleaning duties on the predators almost continuously.

Professor Michael Kingsford, one of the scientists, said: "The manta rays would cease all movement of their fins while in the cleaning stations. Their gills were often flared and mouths open, but never wide enough to suggest feeding. Several 'cleaner' fish would then migrate upwards towards the animal and begin cleaning."

Sharks, meanwhile, would hold themselves in an almost vertical position while the smaller fish went to work, or would "casually swim over the site" in order to receive attention. "Depending on the strength of the current, each interaction would last anywhere between five and 10 seconds before the client would move away from the station and the cleaners would immediately retreat to the reef," Professor Kingsford said.

"The shark clients – in most cases – would swim back around into the current and repeat the process until cleaning had ceased." He said that while cameras had captured more than 1,100 sharks at Osprey Reef, "no feeding or chasing was observed". Both sides benefit, he said, with "the larger creatures cleansed ... and the smaller fish gaining a source of nutrition."