Manta Ray

The manta ray, which is also sometimes called the devilfish, is the largest ray in the world. Highly intelligent and mostly solitary, they are found in all of the world’s oceans except for the freezing cold waters of the Arctic and Southern Oceans. Long-lived and slow to reproduce, the species is vulnerable to overfishing and being harvested for international trade. Despite this, these brilliant creatures are incredibly friendly to human divers, often swimming up to greet them. You can learn all about the gorgeous, misunderstood manta ray below!

Five Incredible Manta Ray Facts!

• Massive Brain: These fish have the biggest brain-to-size ratio of any cold-blooded fish, and they display a level of intelligence comparable to dolphins, elephants, and primates.
• Protected: Since 2011, manta rays have been protected in international waters by an international treaty, the Convention on Migratory Species, and many countries have placed bans on fishing them.
• Distinct from Stingrays: Manta rays evolved from stingrays, but they are a completely distinct species. Unlike stingrays, they don’t possess a barb that can sting, and they are not bottom dwellers.
• Unique Feeding: These fish use creative techniques to get the most out of filter-feeding, including performing barrel rolls to stay in one place and engaging in chain feeding, during which several fish follow each other, creating a cyclonic effect.
• Biggest: The Manta Ray is one of the biggest fish in the world. The largest manta ray ever recorded weighed 5,000 pounds and was caught off New Jersey in 1933. Manta rays have a maximum “wingspan” of up to 30 feet.

Evolution

Because their bodies are primarily composed of biodegradable cartilage and collagen, the fossil records of Manta Rays are incredibly scant, leaving scientists to do guesswork to fill in the missing gaps in their evolutionary history. It is estimated that mantas first branched off from bottom-dwelling rays and skates around 20 million years ago. Somewhere along the line, mantas’ mouths moved from their underbelly to the front of their head, they lost their ability to sting, and grew larger, more wing-like appendages to allow them to swim with much greater ease.

Classification and Scientific Name

These fish are members of the class Chondrichthyes, the order Myliobatiformes, the family Mobulidae, and the genus Mobula. For a long time, the genus was believed to have only one species, M. birostris, but another species, which has the scientific name M. alfredi, has since been identified.

The word “manta” is derived from the Spanish and Portuguese word for cloak or blanket. Traditionally, manta rays were hunted and captured using traps that resembled blankets, and the name stuck.

Types of Manta Rays

For many years, it was believed that there was only one species of manta. In 2008, however, scientists confirmed the existence of two distinct species:

Giant Oceanic Manta Ray (Mobula birostris)

This massive fish is found in all major oceans. It tends to spend most of its time away from shorelines in open water. They can live to be up to 60 years old.

Reef Manta Ray (Mobula alfredi)

The reef manta ray, M. alfredi, primarily lives along coastlines in the Indo-Pacific. It is much smaller than the giant oceanic manta ray. Reef mantas are also considerably more endangered than their giant relatives.

Appearance

These fish have massively wide, flat, triangular bodies with pectoral fins that resemble wings when in motion. Two cephalic lobes extend out from the front of its head, lending it the alternative name “devil fish.” The wingspan of the giant oceanic manta ray can extend up to 29 feet in length, and they can weigh up to 5,300 pounds.

These large fish have lateral eyes, and their wide, terminal mouths are located on the front edge of their heads rather than on the bottom, as with most rays. The two cephalic lobes at the front of its head extend out, allowing water to be introduced to the mouth; these lobes give the fish the distinction of being the only vertebrate animal with three paired appendages.

As filter feeders, they feed by swimming with their mouths wide open, allowing zooplankton and krill to sift through rows of small rakes that line their mouths. These gill plates, or gill rakers, are heavily prized in Chinese medicine.

These fish come in two color types. Some have chevron coloring, with black backs and white bellies, while others are mostly all black. They also have distinctive patterns of spots on their bellies.

Distribution, Population, and Habitat

They are found in all of the world’s oceans. They are split up into small, highly fragmented populations, making it difficult for scientists to arrive at reasonable worldwide population estimates. However, they appear to live in groups of 100 to 1,500 individuals. The largest population is believed to be in Ecuador, where they congregate at places like Machalilla National Park and the Galapagos Marine Reserve.

Due to the popular use of their gill rakers in Chinese medicine, for which there is no scientific evidence of any true health benefits, these fish are vulnerable to overfishing and overharvesting. Worldwide, the gill plate trade nets upwards of $30 million per year. These fish reproduce slowly and have long lifespans, putting their populations at even higher risk.

Both species are classified as Vulnerable by the IUCN, and efforts have been made to counteract this. Many countries have banned the fishing of these fish, including Mexico, Peru, Ecuador, the Philippines, and New Zealand; since 2011, the fishing of manta rays in international waters has been banned thanks to the Convention on Migratory Species.

Predators and Prey

Manta Ray Predators

The primary predators of these fish are large sharks and orcas, or killer whales. Humans also greatly impact the populations of mantas through the pollution of the ocean and illegal poaching.

Manta Ray Prey

These fish are filter feeders, so their diets mostly consist of planktonic organisms like copepods and mysids. Shrimp is another popular staple, and they are also believed to consume fairly large quantities of small- and moderate-sized fish.

Reproduction and Lifespan

Little is known about the reproduction habits and development timeline of manta rays because they are difficult to observe in the wild. Typically, however, males appear to court females by following closely behind them until mating begins. Sometimes, several rays mate together in “trains”; the full moon may trigger this behavior. The male fertilizes the female’s eggs, and a single live pup is typically born after a gestation period of 12 to 13 months. The small pups are miniature replicas of adults and can take off on their own right after being born.

The average lifespan of these fish is about 50 years.

Fishing and Cooking

Mantas are eaten for food in some places, but they are typically treated as a rare delicacy. Scientists have no conclusive data on just how many of these unique rays are left in the ocean, so bans on fishing them are in place in many parts of the world, though many poachers persist. Due to their slow swimming speeds, hunters are able to easily catch mantas with harpoons or large nets.