Manta ray Manta birostris (above). Manta ray Manta birostris silhouetted (below).

Rays are wondrous sea creatures. They are the birds of the underwater world, often captivating divers by their graceful movements and elegant manners. They are found in all ocean from abyssal depths to shallow reefs and estuaries even existing in some freshwater streams.

There are more than 500 different kinds of rays known throughout the world, many with exquisite markings and polka-dots, others with long whip-like tails. They're generally flat bodied, having broad-winged pectoral fins extending from the tail to the sides of the head. When fully grown, rays can vary in disc width from just a few centimetres to more than 6m and weigh a staggering 1360kg. The manta ray is the largest ray and may exceed 9m in width, although documented sightings are yet to be confirmed. Apart from the mantas, which spend much of their time on or near the surface feeding on plankton, most rays live close to the sea floor where they feed largely on invertebrates and occasionally small fish - but many will readily scavenge for food.

All rays bear their young live, except skates, which are oviparous (produce eggs that hatch outside of the body).

Not all rays are flat, or disc shaped. The shovelnose ray (guitarfish) and sawfish are rays that have shark-like bodies with two large dorsal fins of almost equal size. People often confuse these rays with sharks, especially the harmless shovelnose which enjoys a diet of sand-dwelling critters in shallow inshore waters.

Like sharks, rays have a skeleton made of cartilage (not bone); they possess a battery of finely tuned sensory systems for locating prey and their skin is covered in small toothlike projections called denticles.

Identifying the ray group is made easy by the location of the gill openings, which are always on the lower, light coloured surface. The mouth and nostrils are usually located on the bottom of the head and the eyes on top of the head. None of the rays attack people; they all have a docile nature and prefer to flee threatening situations. However, rays should be treated with the respect they deserve as many, such as the electric ray, stingaree and stingray, have very effective defence mechanisms.

The torpedo, coffin and numb ray are all electric rays capable of transmitting powerful electric charges. They have special organs situated behind the eyes on either side of the head, which they use to stun fast moving prey and for defence.

The stingaree and stingray bear one or more venomous spines on the base of the tail, capable of delivering an excruciatingly painful wound. These rays often bury themselves into sedimentary bottoms when resting and if accidentally trod on, will defend themselves by thrusting the tail upwards and forward with remarkable speed to impale the victim. When walking over sandy bottoms a simple shuffle of the feet would prevent any injuries of this kind.

If left undisturbed, many of the large rays will often allow divers to move in close. Some, such as the mantas, will even show surprising curiosity towards the diver, especially when they are being serviced at an underwater fish cleaning station. This allows an excellent opportunity to observe these leviathans closely and a chance for spectacular photography.

The most famous rays in the world known for interacting with divers are without a doubt the southern stingrays (Dasyatis americana) of Grand Cayman Island, situated off the British West Indies. These rays show absolutely no fear of divers and snorkellers, who feed them offerings of fishscraps at a place locals call Stingray City. An experience with these rays is absolutely mind-boggling, one far beyond imagining.

A scuba diver swims amongst Southern stinrays (Dasyatis americana) at Stingray City, Grand Cayman Island in the British West Indies (left). An underwater photographer photographs obliging subjects - the southern stingrays at Stingray City, Grand Cayman Isand (right).

Mantas of the Gulf of California are also very popular. These animals seem to actually enjoy physical contact with divers. The reason still remains a mystery. Unfortunately the future of these mantas is threatened by exploitation by local fishermen and their numbers are sadly dwindling.

The skate is probably the most abundant ray in the ocean but few kinds are seen by divers as the majority live in the deeper waters on the continental slopes. In Europe and other parts of the world, rays and skates are fished commercially as important primary produce, with catches being considerably large in some regions. While world catches are small in comparison with the commercially important bony fishes, controlled fishing measures are nevertheless important if these target fisheries are to survive. Unlike most of the bony fishes, rays generally grow slowly and sexually mature late in life before producing relatively few young.
Should the ray fauna be indiscriminately overfished and mature adults depleted from marine habitats, the effects could prove disastrous by causing severe upset within the sea's eco-system.

We are fortunate in Australia to have some of the richest ray fauna in the world, with 73% being endemic to the region. However, like so many marine animals, we really know very little about these fascinating sea creatures. We can only take care of their environment as best we can and stare in admiration as they glide through our lives.

Text: Meri & Gary Bell
Photography: Gary Bell