The animated film Shark Tale from a few years ago featured a "car wash" for dirty marine dwellers. Now a new study in the journal Marine & Freshwater Research documents something very similar: fish cleaning stations for sharks and manta rays.
(A manta ray with cleaning remora fish attached. Credit: Mila Zinkova)
"The objective of the study was to document the occurrence and frequency of visits by manta rays and sharks to cleaning stations in the northern Great Barrier Reef and at Osprey Reef in the Coral Sea," Michael Kingsford, a James Cook University professor in the School of Marine and Tropical Biology, said.
"The manta rays would cease all movement of their fins while in the cleaning stations," added Kingsford, who is also at the ARC Center of Excellence for Coral Reef Studies. "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."
Kingsford and his team noted that cleaning station sessions with rays could last for several hours.
Sharks behaved a bit differently, taking on an almost vertical pose, which perhaps communicates to fish something like, "I'm ready to be cleaned now."
"Sharks in the vertical posture would typically approach with the tide before pointing head upward towards the surface upon reaching the cleaning station. Pectoral fins pointed down, mouth open, gills flared and a rapid paddling of the caudal fin were typical behaviors," Kingsford and his team wrote. "Depending on the strength of the current, each interaction would last anywhere between 5 and 10 seconds before the client would move away from the station and the cleaners would immediately retreat to the reef."
They continued, "The shark clients- in most cases- would swim back around into the current and repeat the process until cleaning had ceased."
Kingsford said more than 1100 sharks were observed at Osprey Reef. None was observed feeding or chasing, so the sharks seemed to respect the cleaning process and were clearly at the reef for that main reason.
He explained, "Both sides benefit from the interaction with the larger creatures cleansed of ectoparasites, mucus, dead and diseased tissue and scales and the smaller fish gaining a source of nutrition."
Please click here to download footage of sharks, rays and fish gathering at the site. It takes a while to download the silent footage, but it's quite beautiful. While you're waiting, maybe check out the below little clip showing the DreamWorks version of a fish "car wash."