The Giant Oceanic Manta Ray

The giant oceanic manta ray, or manta birostris as it's also known, is the largest ray in the world. Boasting impressive wingspan statistics, this ray is also gentle, intelligent and graceful.

Giant manta ray

© Michael Bogner / Adobe Stock Image

Spotting a giant manta ray

You'll need to head to tropical or sub-tropical climates to be in with a chance of glimpsing a giant manta ray, as they prefer warm temperate coastal regions. They've been spotted in the Atlantic Ocean, around South Carolina in the USA, and near Brazil in South America. You can also find them in the Indo-Pacific, South Africa, New Zealand and the Bay of Bengal. Large populations of giant manta ray are thought to reside in Ecuador and around the Galapagos Marine Reserve.

Most giant manta rays swim on their own, although they've been known to swim in groups of up to 50. They usually stay near the surface of the water, in the middle of the ocean, but will happily descend to depths of 120m to find deep-water sources of food. Unlike other flat fish, the giant manta ray doesn't rest on the seabed, as it needs to keep moving to enable water to pass over its gills for respiration.

Manta birostris tend to travel with the currents and migrate according to where zooplankton is in abundant supply. Occasionally, you'll find rays parked up by coral reefs, where cleaner fish will remove parasites and dead cells from their skin. Sometimes, giant manta rays will jump out of the water, seemingly at play.

Aside from aquariums in Singapore and Japan, there are few other places to visit giant manta rays in captivity.

Features

Giant manta rays have a large body shaped like a diamond, with elongated pectoral fins that look like wings. According to Guinness World Records, the largest wingspan ever recorded for a giant manta ray was 30 ft, with the average wingspan typically measuring between 17-22 ft.

They have two cephalic lobes in front of their mouth, which they can roll up when swimming, or extend to channel food into their mouth.

Giant manta rays have a dark upper body and are pale underneath, although spots and blotches on their skin give them unique markings so that individuals can be identified.

Diet

Filter feeding makes up almost a third of a giant manta ray's diet, where it will gorge on zooplankton like shrimp, krill and planktonic crabs.

Population stats

Giant manta rays can live for up to 20-40 years, but with them only producing one pup every two-to-three years, and a gestation period that lasts one year, their population growth rate is slow. However, they have few predators, with only large sharks and dolphins posing a threat.

Overfishing by humans is the single biggest threat to giant manta ray populations. In particular, the gill rakers are prized in China for making medicines, while the meat is a delicacy in the Philippines.

Manta birostris now has a vulnerable status according to the IUCN's Red List of Endangered Species. In some areas of the Indo-Pacific, numbers of rays have declined by up to 95%.

Increasingly, giant manta rays (who are harmless to humans) are playing a role in dive tourism. Possessing the largest brain of any fish, these rays are thought to be highly self-aware and will even try to gain attention from divers and interact with them.

Whether you would like to go diving with these magnificent giants, or with other types of fish, having the right equipment is essential. Why not take a look at Solent Plastics’ Gear Gulper Equivalent storage boxes, that are ideal for keeping your diving equipment safe and secure?