Spring break is a time when many people dream of tropical destinations for fun and relaxation. In warm waters of the South Pacific, though, little fish have turned the art of relaxation into a tool for survival. In coral reefs, among the limestone skeletons created by colonies of coral polyps, slender, four-inch-long fish, called bluestreak cleaner wrasse, host an extreme "spa" for their ocean neighbors.
Grooming is the specialty at the reef spa. “Clients” swim in to receive a bluestreak treatment. Why? Keeping clean is key to good health for animals living in a soup of microorganisms. Parasites and diseased tissue can weaken marine animals’ immune systems, making them more likely to get sick or fall prey to hungry predators.
Luckily for reef visitors, the striped, bright-blue fish see pests as food. Cleaner wrasse patrol their clients from mouth to tail fin – nipping off parasites, waste and dead tissue. The daring little cleaners even check inside the gills and mouths of larger fish.
Ditching parasites is so important that marine animals of all shapes and sizes gather round and calmly wait their turns. Puffer fish, groupers, sea turtles, nurse sharks, black-tip reef sharks, sand tiger sharks and manta rays have all been spotted at the underwater spa. Divers report that while waiting, natural enemies temporarily call off the chase between predator and prey.
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How does this happen? And how does this extreme groomer manage to pluck a meal from inside a shark’s mouth without becoming lunch? Bluestreak cleaner wrasse soothe big predators with a massage. Using their pectoral and pelvic fins, the little ribbon-like fish gently tickle predatory clients as they clean.
According to scientists at the University of Queensland, Australia, this calming touch leads to fewer predatory chases at the cleaning station. So the cleaner wrasse eats in peace and visitors to the spa enjoy relative safety. Ultimately, the mutual exchange is a great deal for both parties involved; each client rids itself of dangerous parasites and the cleaner wrasse has meals delivered right to its door.
HOW YOU CAN HELP
The coral reefs that provide spa territory are vulnerable to pollution, overfishing and human disturbance. You can help protect them by:
• Make ocean-friendly seafood choices. Get tips at seafoodwatch.org.
• Limit your use of lawn fertilizers and pesticides that may wash into storm drains and local waterways.
• Discourage coral poaching by not purchasing coral trinkets as souvenirs.
• Learn more about cleaner wrasse, nurse sharks, black-tip reef sharks and other tropical reef species at Point Defiance Zoo & Aquarium’s Spring Break Tropical Party Saturday and Sunday.
This month’s column was written by the staff at Point Defiance Zoo & Aquarium.