First published on Mongabay India here.
- Coral reefs host cleaning stations, spaces where animals get rid of parasites from their bodies with help from cleaner fish.
- Cleaning stations provide a vital service in keeping animals, and the reef, disease-free.
- These stations have allowed for important documentation on the behaviour of species using it, thus helping in their conservation. And they’re delightful to watch.
“The most extreme thing about the ocean is its sheer, inconceivable size. In that enormous volume – the biggest habitat on earth – lives a kaleidoscope of animals, plants, microbes and viruses. Indeed, the ocean nurtures the most fascinating and unique creatures in the natural world. They occupy many different habitats and deploy diverse survival strategies.”
– Stephen R Palumbi and Anthony R Palumbi in The Extreme Life of the Sea.
One of these many strategies is an intriguing symbiotic understanding between two sets of species. Under the ocean’s surface, coral reefs – the rainforests of the seas – build tiny worlds within them. Reefscapes act as towns in the giant ocean, which animals use for homes, food, shelter, and sometimes, a thorough spa treatment. In other words, reefs facilitate cleaning stations, small little spas or nature’s very own idea of a car wash in the ocean!
A cleaning station is a space on a reef that is marked by the presence of cleaners – more often than not, wrasse fish and shrimp. They provide ‘cleaning services’ to animals that need it – called what else but, the clients. Larger creatures like turtles, mantas, sharks (in deeper waters) and smaller fish (parrotfish, pufferfish, needlefish, groupers, surgeonfish) stop by to get ectoparasites (annoying tiny bugs that make their homes in unreachable spots on client bodies) and dead skin eaten off by cleaners from their bodies, gills, fins and carapaces.
Simply put, the cleaners get food, the clients get cleaned.
Road signs in the deep
Cleaning stations exist across different depths and topographies, at 5 metres or as deep at 100 metres. How do animals, traversing through this vast big blue, know that these services exist close by? Does the reef provide the necessary roadside signage?
“They probably use a range of cues to get to them,” said marine biologist Shreya Yadav. “Since stations can stay in the same spot for a while, I would think resident fish know about them. Roving species probably spot them while they’re swimming past, and stop if they need to. I’ve noticed quite a few on the reef slope, where they are visible to many passing schools of fish.”
Umeed Mistry, photographer and scuba diver, said, “Residents might know where it is, but many pelagic rays/sharks also visit these places. These stations attract creatures from many parts of the reef, plus many animals on long distance migrations also stop at convenient stations to be cleaned. In fact, there are other kinds of cleaning as well, where herbivorous fish eat algae off other animals; and makeshift stations around floating debris where congregating fish provide the same service in the open ocean for creatures coming up from the deep.”
(Cleaning and) counting stations
Biologists are also using cleaning station sites to further conservation data for some species. For example, mantas spend a fair bit of daylight-hour time (40 percent) at a cleaning station, because cleaners sleep during the night. In a recent paper, scientists suggest that “assuming that both cleaning and feeding are crucial for the mantas’ survival, there is probably a trade-off between the two activities. A mantas’ decision to visit a cleaning station is probably dictated by (1) feeding effectiveness (i.e., plankton availability, distribution, and concentration); and (2) cleaning effectiveness (i.e., cleaner fish activity hours and service quality).”