Like cars lined up at a car wash, sharks and rays gather at ocean cleaning stations that new research finds are mostly located at seamounts. There, hungry and detail-driven cleaner wrasse fish rid sharks of dead skin, external parasites and other undesirables.
SLIDE SHOW: Super Shark Senses
The study, published in the latest PLoS One, could help to explain why many oceanic sharks regularly venture into shallow coastal water. At such places, they are more vulnerable to humans -- their #1 predator -- but cleaning off must be more important to them.
Simon Oliver, a researcher at the University of Wales, Bangor, School of Ocean Sciences, and colleagues focused their investigation on interactions between thresher sharks and cleaner wrasse at a seamount in the Philippines. Seamounts are underwater mountains that rise above the ocean floor.
PLANET GREEN: Sharks: A Bleak Future Ahead
Oliver and his team observed the sharks at the site for an incredible 1,230 hours. Analysis of those recorded observations revealed that sharks prefer to get their scrub down in the morning. Cleaning activity gradually dies down throughout the rest of the day.
"Cleaners showed preferences for foraging on specific areas of a thresher shark's body," the scientists write. "For all events combined, cleaners were observed to conduct 2,757 inspections, of which 33.9 percent took place on the shark's pelvis, 23.3 percent on the pectoral fins, 22.3 percent on the caudal fin, 8.6 percent on the body, 8.3 percent on the head, 2.1 percent on the dorsal fin, and 1.5 percent on the gills respectively."
We can then speculate that a lot of gunk collects on shark pelvises as they go about their daily business.
Happiness in sharks hasn't yet been studied or proven, but my bet would be that shark bliss occurs at these seamount stations. To facilitate the cleaners, the sharks were seen swimming in a standing position, doing ballet-like twirls so that the fish washers could get at every nook and cranny.
The cleaner wrasse did not discriminate between male and female sharks, suggesting both get equally dirty. Sharks that spent more time at the seamount station received more fish inspections, so the best bathing requires time and patience.
Sharks must be good customers, paying with their bodily food rewards.
"The cleaner-thresher shark association reflected some of the known behavioral trends in the cleaner-reef teleost system since cleaners appeared to forage selectively on shark clients," the researchers explain
"Evidence is mounting that in addition to acting as social refuges and foraging grounds for large visiting marine predators, seamounts may also support pelagic ecology by functioning as cleaning stations for oceanic sharks and rays," the team concludes.
Hopefully conservationists can target such areas for greater protection, making it easier for sharks to get their healthy, necessary, and probably very enjoyable cleanings.
Here's a closer look at thresher sharks:
Photo credit: NOAA
Tags: Animal Behavior, Animals, Fish, Marine Life, Oceans
comments ( )