Oceanic manta ray

Oceanic manta rays (Mobula birostris) have huge, diamond shaped bodies and swim by beating their ‘wings’ up and down together. They can also beat them in opposite directions – one up, one down.

Although once thought to migrate seasonally to the waters around northern New Zealand, research on other populations in the Indo-Pacific region suggests that the oceanic manta seen in our waters during spring and summer each year may be resident in this part of the southwest Pacific.

We consider manta rays harmless. But divers have occasionally been towed through the water at high speeds when mantas have become accidentally tangled in their float lines.

How to identify oceanic manta rays

Oceanic manta rays have diamond-shaped bodies and two large muscular fins that protrude forward from the head either side of their mouth. These are called their ‘cephalic fins’. They use these for feeding and roll them up to improve swimming efficiency when not in use.

While rolled up, oceanic manta rays' cephalic fins resemble horns. This has given rise to their alternative common name of ‘devilfish’.

Manta rays do not have a functional barb or sting on their tail. But the oceanic manta has a large swelling at the base of the tail close to the dorsal fin where a sting is buried in. This sting has become functionless as they’ve evolved.

If you see an oceanic manta ray or devil ray, report it to DOC at sharks@doc.govt.nz. You can also support citizen science by reporting oceanic manta ray sighting to Manta Watch New Zealand.

Similarities with devil rays

Oceanic manta rays are closely related to the reef manta ray (Mobula alfredi) and their smaller relatives, the devil rays (Mobula spp.).

The reef manta is common throughout the central and western Pacific and Indian Oceans but has not yet been found in New Zealand waters. It differs from the oceanic manta in having dark spots between the gills on the underside of the body, and the pale shoulder blazes on the upper body angle back towards the tail forming a V-shape. They also do not have a vestigial sting. 

The only devil ray so far recorded from New Zealand is the spinetailed devil ray (Mobula mobular; formerly Mobula japanica). It has a dark band over the head, a white tipped dorsal fin, an undershot mouth and a very long, thin tail with a short spine at its base. By comparison the oceanic manta ray has

• a much broader head
• larger cephalic fins
• a terminal mouth
• no teeth in the upper jaw
• a faint v-shaped white marking in front of the dorsal fin

Oceanic mantas’ shoulder markings form a t-shape
Image: Dr Mark Erdmann

Reef mantas’ shoulder markings form a v-shape
Image: Dr Mark Erdmann

Several species of devil ray have a white tip to the dorsal fin, whereas the manta ray’s dorsal fin is all black.

More about this species

Range and habitat

Manta rays occur in open water, in tropical and some warm temperate regions of the world. They live in shallow water close to shore and in the open ocean. Although they spend most of their time swimming, they sometimes rest on the bottom.

Researchers once thought there was only a single globally distributed species of manta ray. However, in 2009 two species were recognised: the oceanic or giant manta, and the reef manta.

Both species are globally distributed. More recent research suggests there is a third species in the Northwest Atlantic.

The oceanic manta is the only manta ray recorded from New Zealand. It’s been recorded off east and west coasts of the upper North Island, mainly from spring to early autumn. The distribution of reported sightings off the northeast coast closely matches the course of the East Auckland Current.

In 2024, the Hauraki Gulf was recognised by the IUCN Shark Specialist Group as a habitat of significance for oceanic manta rays.

E-Atlas - Important Shark Ray Areas

Diet and foraging

Little is known of the diet of oceanic manta rays in New Zealand, although they are often seen feeding on dense patches of zooplankton. To eat, they use the large fins on either side of their head to funnel water containing these tiny organisms into their mouths.

Oceanic manta rays trap zooplankton on their distinctive filter plates and periodically swallow. These filter plates are attached to the arches of their gills. They often swim in repeated backward loops or ‘somersaults’ to remain in a dense patch of plankton.

Life history

Female manta rays give birth to single pups. Pupping probably occurs during spring. Size at birth is 122-190 cm disc width, and we suspect gestation to be over a year. 

Manta rays sometimes jump out of the water. Even large adults are capable of this. The reason manta rays do this is unknown, but it may be to remove parasites or sucker fish (remora).

Manta rays are host to a variety of external parasites. Reef and oceanic mantas regularly use cleaner stations on coral reefs where reef fishes like damsel and butterfly fishes pick these parasites off them.

The largest accurately measured oceanic manta ray was 670 cm disc width (wing tip-to-wing tip) but they are reported to reach 910 cm disc width. Individuals estimated to be between 200-790 cm disc width have been reported from New Zealand waters.

Threats to manta rays

Oceanic manta rays have a small population size and a low birthing rate of only 1 pup every other year. This means they have low resilience to fishing pressure.

Coastal development, pollution and human disturbance also threaten many manta populations. This causes habitat loss, reduces their food sources and disrupts their natural life-cycle.

Manta and devil rays are protected in New Zealand and there is no reported by-catch of oceanic manta in our waters. Fisheries targeting manta and devil rays occur in several other countries. These include India, Sri Lanka, Indonesia, and the Philippines. There is also growing concern overseas about the use of manta rays for medicines.

Manta rays are classified as Endangered globally by the IUCN Red List of Threatened Species.

DOC’s work with manta rays

DOC undertakes research on protected fishes, including manta and devil rays, to improve our understanding of their distribution, overlap with fisheries and to monitor their conservation status. We collaborate with Manta Watch NZ and Conservation International on oceanic manta ray research in New Zealand.

Oceanic manta rays are protected under the Wildlife Act 1953. Since 2011, it has been illegal to hunt, kill or harm manta rays within New Zealand’s national waters (200 nm limit around New Zealand). Any offence under this Act is liable to a fine of up to $250,000 and six months imprisonment.

Fishers and bycatch

It is not illegal to accidentally catch a manta ray, but it must be released alive and unharmed. Report the catch to DOC and/or Ministry of Fisheries as soon as possible. DOC may ask you to land the dead manta ray for scientific research.

Trade in any part of a manta ray is illegal.

How you can help manta rays

Report sightings to DOC and Manta Watch New Zealand

If you see an oceanic manta ray, let us know and help guide work that can support and protect them.

Report sightings, strandings or captures to the DOC Marine team by emailing sharks@doc.govt.nz or call 0800 DOC HOT (0800 362 468).

Report your sighting to Manta Watch New Zealand

By reporting your sighting to Manta Watch New Zealand you can support other research on oceanic manta rays in our waters. This will help confirm if New Zealand has its own distinct population of oceanic manta rays and work to estimate their population size.

To report a sighting, use the Manta Watch NZ mobile app or the manta ray sightings form below.

Report a sighting to Manta Watch New Zealand

Inform us if you inadvertently kill a manta ray

Very little is known of the biology of oceanic manta rays. So dead specimens are of considerable scientific value.

Should you inadvertently kill an oceanic manta ray, notify DOC. We may ask if you can bring it to shore, if possible. Useful information to provide includes the location and depth that the fish was taken in.

Other ways to help

• Do not buy manta ray products when travelling abroad. You may find manta ray skin used for leather in some products abroad. Some traditional Chinese medicine also use their filter plates from their gills.
• When operating a boat around manta rays, try to minimize the disturbance and risk to them. Travel slowly and quietly and do not obstruct their movements. Avoid load noises or sudden movements.
• Although manta rays may tolerate divers touching them or riding on their backs, avoid interacting with them in this way. It is illegal and can remove the protective mucus layer covering their skin and cause infections and blistering.
• When fishing, carefully release any unwanted sharks and rays.
• Do not throw away plastics, nylon fishing line, and other types of rubbish at sea. Like whales, large filter-feeding sharks and rays can accidentally eat these or become entangled in this debris.

More information

• Fish Base species summary
• Foundation for the Protection of Marine Megafauna
• The Manta Network