Island Species: April 2011 Archives
Within the animal kingdom, sharks are known for their sharp teeth, and their increasingly threatened conservation status due to the popularity of shark fin soup. But now, a study suggests that sharks are also unique for the importance they place on good hygiene and healthcare!
Scientists at Bangor University in Wales have observed thresher sharks (seen in image below) visiting shallow coral reef ecosystems near the Philippines for what appear to be full-body cleanings. Upon arriving at the reef, the sharks slow down and swim in a small circle, apparently to attract the cleaner wrasse, a small fish with excellent shark-grooming skills.
One scientist describes the process as "a bit like a surgery...The sharks come in with cuts and scrapes where they might have scabs and these are treated by the cleaner wrasse, which remove dead tissue from the wound area and any parasites from the skin." The sharks remain for their cleaning for up to 45 minutes, swimming in small circles near the reef.
This shark medical care is just another example of the often surprising interactions between different species within an ecosystem. Unfortunately, with threats to sharks on the rise, sometimes a trip to the cleaner wrasse may have a tragic ending. The shallow reefs where these cleanings take place are often shared by fishermen, who either hunt the sharks (or, more brutally, remove only their fins), or use dynamite or hooks on other marine species, inadvertently killing the sharks along with them. These practices, along with irresponsible tourists who hurt the reefs while observing the sharks, also cause immense harm to the cleaner wrasse fish and all other species who depend on the coral reef.
Image courtesy of NOAA