Diving Papua New Guinea: Milne Bay Manta Rays – Giants @ Home
I think it’s the mixture of fear & awe that creates the adrenalin that makes encounters with large marine creatures such exciting & memorable underwater events. You are after all, just a temporary visitor to their environment, in which they are in full control and gracing you with their presence.
Giants @ Home
Fear is a function of experience & knowledge and I can vividly remember my first encounter with a large shark, an inquisitive sand tiger, in the Seychelles over 20 years ago and I really thought I was going to die.
I now know that I was in no danger at all, but the fact is that perception is reality and I clearly perceived that my life was about to end!
Since then I have been fortunate to have numerous encounters with a variety of large creatures and while I no longer fear for my life, I still experience a strong tinge of fear, mainly of the unknown and what could happen if I judge the situation wrongly.
Awe is the emotion that I feel most strongly during such encounters, because it’s a basic fact that over fishing, pollution and climate change are dramatically effecting the marine environment and opportunities to interact with large marine creatures are occurring less & less. So being in close proximity to such creatures is an experience that always fills me with a sense of wonder at the grace and perfection that thousands of years of evolution have created.
Diving Papua New Guinea: Diving with the Milne Bay Mantas
I have to say I was rather skeptical when I arrived in Alotau to board the MV Golden Dawn for a 10-day trip in Milne Bay and heard the boats skipper & owner, Craig de Wit, describing the manta encounters the last party of divers had experienced.
Milne bay Manta Ray
Craig was waxing lyrically about how large numbers of mantas frequented a cleaning station just off the beach of a small island near the former provincial capital of Samarai Island. Not only were they there on a reliable basis, but they had learned to like the feel of diver’s bubbles on their underbellies and would just hang there savoring the experience.
Plus some liked to have their bellies scratched, which was done by reaching your hand upwards prior to the manta coming in and as they approach they rub their belly on your hand!
I kept my thoughts to myself, but was convinced this would turn into one of those “you should have been here last week” situations, but I was wrong, completely wrong!
The island Craig was referring to is Gona Bara Bara, located just up the China Strait from Samarai Island at the south-east tip of Milne Bay, and the discovery of the cleaning station is a story in itself worthy of telling.
Golden Dawn had been charted to search for mantas and Craig had gone to all the known Milne Bay locations but did not find a single one. Then in an act of inspired desperation he responded to the pleas of James, the boat’s engineer, to check out his home island where there were “lots of mantas just off the beach”.
Here is how Craig described finding them:
“I discovered the cleaning station when we went to the island, James my engineer kept insisting that he had lots of mantas at his island so we went in search of them. On arriving we saw them around the place on the surface so most of the group went for a snorkel in hope of getting close to them. I went for a dive along the beach hoping to get close and while drifting along in the current came across the cleaning station and I guess the rest is now history.”
Milne Bay Manta
Golden Dawn managed to keep the site largely to itself for about two years and during that time Craig identified about 30 individual mantas. Then as word spread about the cleaning station and other boats started to visit the site, Craig expected the mantas to move away. But it seems the opposite happened and as the mantas became more familiar with divers their aversion to the exhaust bubbles produced by scuba gear went away.
On that trip we spent two days with the mantas on that trip & everything that Craig told us at the airport was indeed true and when I went back the following year on Rob van der Loos’ boat MV Chertan, we had a similar two-day experience.
The cleaning station is actually a solitary bommie in about 9m of water, standing in an otherwise featureless sandy area just off the beach at Gona Bara Bara. The bommie rises up about 5m and is inhabited with a variety of soft corals and fish, including many small cleaner wrasse that provide the parasite removal service that the mantas need.
When the current & tidal conditions are right the mantas are at the bommie when you descend and the key is to move slowly and get in position to photograph them as they take turns coming in to be cleaned. If you are really careful it’s possible to get in really close to the bommie, but you need to be sensitive to getting in the way of other divers as they try to get their images. Also the cleaner wrasses assume you have come to be cleaned and start to look for edible parasites on you & I had wrasses trying to clean my yellow gloves. On the previous trip a female diver had one of her earrings removed temporarily by an over zealous wrasse, only to see it spat out again!
Diving Papua New Guinea: Underwater Photography & the Mantas
Mantas are incredibly photogenic creatures – their shape, size and sheer presence simply demands to be photographed. But to get a great image you need to be close and use a wide-angle lens such as the Nikon 10.5mm fish-eye, Tokina 10-17mm fish-eye zoom or ultra wide-angle adaptor for a digicam.
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Milne Bay Manta at a Cleaning Station
The problem is that it’s really difficult to get close to a manta when they are in open water as they keep moving and can swim much faster than you can, so chasing them is simply not an option – it’s best to just hang there and hope that their natural curiosity will bring them to you.
Cleaning stations are definitely the best choice because the mantas have to stop to be cleaned and this usually happens just above the bommie as it hovers and allows the cleaner wrasse to feed on the parasites.
Most cleaning stations seem to be located in a channel or where there is a current running and the manta will pass over the coral head and hover whilst being cleaned.
Good judgment is needed on how close you should try to get as you don’t want to scare the manta away because it won’t just spoil your day, but all the other divers as well and you may not be too popular back on the boat!
Avoid sudden abrupt movements when you are maneuvering into position and be prepared to be patient and back away from the station if you do scare the manta away and generally they will come back.
Milne Bay Manta
Apart from when they are actually being cleaned the mantas are constantly moving, so you need a shutter speed of at least 1/125 second if you want your images to be sharp.
The underside of mantas are usually white, bright white… which is very easy to overexpose so if you are going to shoot from beneath, point your camera into the open blue water and if you are shooting on manual adjust the f stop until you get the correct exposure in the meter.
Alternatively set your camera to shutter priority with the shutter speed at 1/125 second and let the camera adjust the f stop automatically.
Most importantly set your strobe to either a 1/4 power or 1/2 power otherwise you will overexpose the white underbelly.
With this combination you should expose the background correctly and get a nice shade of blue which will look great around the manta, whilst not over-exposing the white underside. As always, check the results & the histogram and make any adjustments you feel are required.
Diving Papua New Guinea: Manta Ray Image Gallery
Diving Papua New Guinea: About Mantas
Early fishermen called them Devilfish because of their size and sinister bird like shape, however they are actually gentle giants who pose no threat at all. Unlike many other rays such as bull rays, mantas do not possess a sharp & venomous spine at the end of their tail that is used to such devastating effect if they attack a potential predator.
Manta rays belong to the elasmobranch, or strap-gilled, group of fish – along with sharks that they are closely related to. What makes this group different from other fish is their skeletons are made of cartilage & gristle rather than calcified bones.
Unlike sharks which are all carnivores, mantas feed on plankton & krill which they scoop into their large mouths by the strange flap like appendages called cephalic fins, which unfurl below them.
They really are giants and the average size of the Manta rays at giants@home was about 5m from wingtip to wingtip, but they are known to grow in excess of 7m and the largest recorded specimen was taken off the coast of India weighing in excess of two tons.
Mantas are believed to give birth to only a single live pup, which emerges from it’s mother’s body wrapped in it’s wingflaps.
Mantas are generally solitary creatures, although loose groups of three to six animals have been observed as have larger groups of up to 30 have been observed herding a large concentration of krill in the manner of sheep dogs. They do this by several mantas somersaulting in tight loops together so that they force the krill into a concentrated ball, which is subsequently devoured by the mantas on their next pass.
Diving Papua New Guinea: Manta Ray Cleaning Stations
Cleaning stations are the underwater equivalents of de-militarized zones, in that, normal predatory behavior is suspended temporarily whilst the tiny parasitic crustaceans that infest most marine creatures are removed.
Milne Bay Manta
The cleaning is done by a variety of small creatures from shrimps, to gobies & wrasses but the common denominator appears to be that they have all developed stripes to identify themselves & their services to their potential customers – all of whom are much larger creatures who could quickly devour them should the truce be suddenly called off!
The larger creature enters the cleaning station and typically signals it’s needs by assuming a trance like posture, often with gills extended outwards so that the cleaners can get access to the most difficult areas. It is quite normal to see large fish with their mouth’s wide open and the cleaners foraging in the deepest recesses.
The mantas at giants@home take up this trance like posture as they hover just above the bommie and the cleaner wrasse search for and remove the parasites.
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