(3 of 3) MANTA RAY - Demystifying this enigmatic creature of the deep
Continued from 2 of 3 MANTA RAY
TO RIDE; OR NOT?
AUSTRALIAN GEOGRAPHIC photographer, Mark Spencer,tackles the sensitive issue of riding manta rays after doing just that off San Benedicto Island, Mexico.
Some people may disapprove of my actions and I fully concur that wild animals generally shouldn't be touched, but when the 4-metre-wide manta positioned itself directly beneath me, barely moving, I knew it was inviting me to "hop on". Taking a few deep breaths through my snorkel, I dived down and gently placed the flat of my hand on its back, which caused a muscle to quiver in what seemed to be a sensuous response. Then, with both hands holding on to the hard, rounded edge of the manta's upper lip (rostral edge), and with knees resting on either side of its spine, I was taken for the ride of a lifetime.
As it beat its "wings", I felt the manta's muscles bunch then stretch, propelling us through the Pacific Ocean with the grace of a bird in flight. The skin, stretched taut from the base of the wing to the spine, was rough and sandpaper-like when I ran my hand forward, but smoother and almost polished in the reverse' All too soon, my lungs cried out for air and reluctantly I returned to the surface.
It'd taken nearly two days of diving at a small seamount beside the island of San Benedicto - where I'd heard a group of about 12 large mantas allowed people to ride them - before one allowed me this intimacy. The seamount is a submerged volcanic plug rising almost vertically from a depth of some 60 metres to within 6 m of the surface. The mantas inhabit the waters around the seamount because of a cleaning service provided by clarion angelfish - a bright orange fish found only in a small area of the eastern Pacific.
Why did this manta allow me to ride it? It's possible it saw me as a big cleaner fish. But it seemed to me that the manta simply enjoyed the interaction.
Later that day while diving with the mantas, I saw how they sometimes discourage people from hitching a ride. One of them inverted itself, and, suspended upside down, stared at me as though asking: "How do you intend getting on my back now?"
I've dived with mantas throughout the world, and have concluded that without doubt, the behaviour of the San Benedicto mantas is unique - it's highly unlikely that even a large manta in Australian waters would want to be ridden. When a wild animal seeks out human interaction, however, I believe it's up to the individual to either deter the animal or indulge it. Regarding the possibility that touching these mantas might unwittingly cause skin irritations or infections, I can only say that I saw no evidence of this where divers regularly hold them around the snout area.
Manta rays and human beings are obviously very different from one another - in appearance and the environment they inhabit - yet the mutual curiosity and trest I shared with some of these creatures off San Benedicto Island convinced me that we have more in common than people generally assume.
DEVIL MAY CARE
Derived from the Spanish word for cape, the word "manta" is now synonymous with this intriguing marine creature. In centuries past, however, it was known as the "devil fish" for its cephalic lobes or "horns", and was believed to be aggressive and harmful to humans. Stories told by sailors and fishermen had the manta capsizing small fishing boats by leaping out of the water and crashing down upon them. This could have a basis in fact as mantas do launch themselves out of the water from time to time, but their motivation is hardly malicious: scientists believe they're simply trying to remove parasites that feed on their flesh.
Another misconception is that mantas drown swimmers by wrapping their pectoral fins around them. It's more likely that mantas have become entangled in boat mooring lines and, given their weight and strength, have nearly pulled boats under - the boats' passengers then wrongfully fearing the manta's retribution.
Throughout the 1800s and until the mid-1900s, manta rays were commercially hunted by being harpooned from small fishing boats in tropical waters throughout the world. As with sharks, the skin on the dorsal (upper) side of a manta ray is covered with denticles - raised, tooth-like scales - which made it useful as sandpaper. The animal's liver, rich in oil, was also deemed valuable. Today, mantas are rarely hunted - they're more valuable to the tourist trade as people flock to coastal destinations off Hawaii, Japan and northern Australia to swim with them in the wild.
Caption 10:A)Choosing to play loop-the-Ioop with a curious diver rather than be ridden, a manta displays its ventral surface (top). A small school of mantas off Mexico take human interaction one step further by allowing divers to ride on their well-muscled backs (above).
Caption 11:A)While people do ride manta rays, touching them can be detrimental. They're coated with slime, a sugar-based substance known as glycoprotein, which reduces surface tension or drag. It also plays a role in preventing infection. Once the slime is removed by parasites, remoras or in some cases, human contact, the manta's skin can develop pink lesions.
A)The diminutive size of the blue-streak cleaner wrasse belies its position as one of the ocean's most effective cleaners. Many marine species, including the 30 cm long chameleon parrotfish, make good use of its services.(left :Scarus chameleon.Right Labroides dimidatus
B)Teira batfish fin against the current under the still-attached mast of THE SEVERANCE, which sank off Lady Elliot Island in 1999. Found singly or in small schools, the teira batfish is commonly encountered in the tropical waters of Australia.(Platax teira)
C)Lady Elliot Island dive instructor Jason Taylor watches the wriggling antics of a zebra shark at Lighthouse Bommie. This shark is most often seen on or near the sea floor, where it uses flat, grinding teeth to feed on molluscs. (Stegastoma fasciatum)
D)Green turtles enchant snorkellers and divers off Lady Elliot year-round. Their presence in the water is supplemented by land sightings during October and November when they come ashore in their hundreds to lay.(Chelonia mydas)
E)ALL IN THE FAMILY - While few may know that sharks and rays are distant cousins, examining their physical structures reveals more than a passing family resemblance.
E1)GREY REEF SHARK (Carcharhinus amblyrhynchos)A medium-sized whaler shark, the streamlined grey reef shark inhabits coral outcrops throughout Australia. It has the classic silhouette that fits the image most people have of sharks.
E2)ZEBRA SHARK(Stegastoma fasciatum)Unaggressive and with a rounder profile than the grey reef shark, the zebra shark rests on the ocean flooras do rays - on its enlarged pectoral fins.
E3)BANDED WOBBEGONG (Orectolobus ornatus)A bottom dwelling shark, the banded wobbegong has a flattened head and body, similar to that of a ray.
E4)WHITE-SPOTTED GUITARFISH (Rhynehobatus djiddensis) Also known as a sandshark - a misnomer as it's actually a ray - the white-spotted guitarfish has the body of a shark and the head of a ray.
E5)BLUE SPOOTED MASKRAY (Dasyatis kuhlii) The blue-spotted maskray's pectoral fins have taken on a wing-like appearance, while two spines on its tail take the place of a dorsal fin.
E6)MANTA RAY(Manta birostris)The shape of a manta's pectoralfin tips bears close resemblance to those of sharks. Given its habit of swimming with fin tips poking out of the water, a manta ray is often mistaken for two sharks swimming close together
A)Unprotected manta rays were hunted, in particular off the coasts of Mexico and Florida (below), during the early to mid-1900s. Then, and still now in Mexico, they were valued for their thick, abrasive skin and oil-rich livers.(picture- Library of Congess, Prints and Photographs Division. LC-USZ02-112831)
B)These manta seekers on a Lady Elliot glass-bottom boat tour have a more benign intent.