Ocellated Eagle Ray

The Ocellated Eagle Ray (Aetobatus ocellatus) is a majestic semi-pelagic species distinguished by its bird-like wing flapping and a dark back covered in white spots (ocelli).

Unlike bottom-dwelling rays, Eagle Rays are active swimmers often seen gliding in the water column around Japanese Gardens and the south coast of Koh Nang Yuan, searching for mollusks and crustaceans.

These rays are shy and sensitive to bubbles; encountering one on Koh Tao is a highlight that requires excellent buoyancy and a calm approach to witness their graceful movement.

Learn about the Ocellated Eagle Ray on Koh Tao

The Ocellated Eagle Ray is seen by scuba divers and snorkelers in the sea around Koh Tao.

The species we see around Koh Tao is the Aetobatus Ocellatus, commonly called the Ocellated Eagle Ray.

It is sometimes mistakenly called a Spotted Eagle Ray or White Spotted Eagle Ray, but these names belong to different species: the White Spotted Eagle Ray (Aetobatus narinari) of the Atlantic and the Pacific White Spotted Eagle Ray (Aetobatus laticeps) of the tropical East Pacific Ocean.

Where to find the Eagle ray on Koh Tao

The Ocellated Eagle Ray is often seen at Japanese Gardens dive site by snorkelers and freedivers who see these magnificent creatures around the south coast of Koh Nang Yuan .

They can also be seen near Sairee reef, where morning swimmers have reported sightings of them during the lockdown of 2020.

How to Identify an Ocellated Eagle Ray

An Ocellated Eagle Ray’s dorsal surface is dark greenish to almost black with white spots. It has a long tail and a flat snout that looks like a duck bill, and the underside or ventral surface is white.

The disc of an Ocellated Eagle Ray is much wider than its length and can be as wide as 330cm but the average size is around 160cm for females and 130cm for males and they can weigh up to 230kg.

They have five small gills on each side of the front half of the belly and the tail varies in length from equal to the disc length to 3 times longer and the Ocellated Eagle Ray has 2-6 venomous spines behind the dorsal fin.

Ocellated Eagle Ray Characteristic Behaviour

• Eagle Rays use their snouts to dig in the sand to look for food and when they find it they use their strong jaws and chevron shaped teeth to crack open hard shells and crush their preferred prey, which include Gastropods, Molluscs, Crustaceans, Worms, Octopi and fish.
• The Ocellated Eagle Ray is a semi-pelagic species and is found at depths of 60 metres right up to the surface in mainly costal waters and near Coral reefs.
• You will often see them in pairs but they do associate in groups and are occasionally seen solitary.
• The Ocellated Eagle Ray is ovoviviparous, which means that eggs hatch inside the body of the female. The embryos feed on yolk sacs initially and later receive additional nutrients from the mother via indirect absorption of enriched uterine fluid.
• The gestation period lasts 12 months and produces only 1-4 pups and they are around 33-36cm wide at birth with newborn pups that look just like their parents except much smaller.
• This species reaches sexual maturity between the ages of 4 and 6 years and can live 25 years.

Interesting Facts about the Occellated Eagle ray

The Ocellated Eagle ray has recently been redescribed as a separate marine species from the Atlantic White Spotted Eagle Ray (A.narinari) and the Pacific White Spotted Eagle Ray (Aetobatus laticeps), found in the tropical East Pacific.

This population, living in the Indo-west pacific is the Aetobatus Ocellatus aka as Occellated Eagle Ray and this recent distinction was made between the rays that differ slightly in terms of genetics and morphology.

Sharks are the principal predators of eagle rays and have also been reported to follow Spotted Eagle Rays during the birthing season, feeding on newborn pups.

Endangered Species

The IUCN classes the Ocellated Eagle Ray as Endangered. An earlier evaluation in 2006, conducted before the ray was assigned three separate species, had listed the Eagle Ray as Near Threatened.

The Pacific White Spotted Eagle Ray’s conservation status has not been evaluated.

Unregulated overfishing and accidental bycatch are the main threats but pollution and the aquarium trade are also threats, together with the low reproductivity of Eagle Rays and its natural rarity.