A diver’s magical find shows ‘cleaning station’ of highly endangered devil rays in KZN
Aliwal Shoal, one of two Marine Protected Areas (MPA) on the KwaZulu-Natal South Coast, is a world-renowned dive site attracting adventurers looking to swim with hundreds of sharks of varying species, including black tips and ragged-tooth sharks.
It has emerged that Aliwal Shoal is also home to several highly endangered shortfin devil rays that use the area as a cleaning station.
Michelle Carpenter, a KZN diver and PhD student specialising in sharks and rays, discovered the Aliwal Shoal devil ray cleaning station in 2020. At the time, she didn’t realise how many rays lived in and frequented Aliwal Shoal.
"I’ve been working on my project for over a year now. I have been overwhelmed by the incredible ray diversity as well as the numbers I encountered. In fact, Aliwal Shoal has even more diversity in terms of rays than it does sharks," she said.
Rays, which are the dorsal-ventrally compressed or flattened sharks, do not always draw as much attention as sharks. However, both sharks and rays belong to the cartilaginous group of marine fishes, elasmobranchs.
Carpenter said the site was home to one of the world’s first discovered devil ray cleaning stations, following another such discovery at Bazaruto Archipelago.
She said cleaning stations were areas on a reef that marine animals, such as a ray, turtle, shark, or fish, visited to have parasites removed or wounds cleaned by cleaner fish.
"These sites function as resting areas and mating grounds for hundreds of marine life species," she said.
Aliwal Shoal, which is 4km off the coast of Umkomaas in KwaZulu-Natal, is one of two MPAs found in the region. The other is Protea Banks, which is 7.5km off Shelly Beach. MPAs have been established to keep marine ecosystems working harmoniously as well as to protect the ocean life under the National Environmental Management: Protected Areas Act. The two are home to a variety of big marine life such as sharks, whales, turtles, rays, kingfish, yellowfin tuna and barracuda.
“Some places, including Tofo in Mozambique, have experienced a decline in sightings of these rays by more than 90% over the past few years. This makes the discovery at Aliwal Shoal that much more profound. It’s not only the numbers of devil rays but also the diversity of ray species that is so astounding," she said.
Carpenter used her scuba diving equipment and freediving to gather the necessary information
"Scuba diving has been the most useful tool in achieving research tasks such as deploying remote cameras to collect footage of cleaning rays and performing transects of the reef communities, including coral and fish,“ she said.
“Sharks and rays have two additional senses that we do not possess. These are the lateral line which detects water displacement, and ampullae of Lorenzini which detect electric pulses.
“I find that the bubbles generated while scuba diving often scares the ray before it approaches you. I have been immersed by a school of 50 devil rays, hugged by a giant manta ray, nearly sandwiched by two barrel rolling giant manta rays, and been face-to-face with spotted eagle rays. It is truly magical."
Her freediving fieldwork is supported by Freediving South Africa.