Marine Creature: Manta Rays (Reef & Giant Oceanic)
Kindly compiled by Guy Stevens of The Manta Trust
Giant Oceanic Manta Ray (Manta birostris) and the Resident Reef Manta Ray (Manta alfredi) are cartilaginous elasmobranch fish and belong to the same group of fishes as all the sharks and other rays. They evolved around 20 million years ago.
Manta Rays are found at worldwide locations in tropical or warm temperate waters between 35° N and 35° S latitudes.
Although manta rays have around 300 rows of tiny teeth in their lower jaws they are not used for eating. They are blunt and are only used in the courtship rituals.
Manta rays sleep by reducing their movements and swimming in small, slow, circular patterns whilst shutting off parts of their brain. Like sharks, if manta rays were to stop swimming they would sink.
- Lifespan: 40-50 years
- Size: Average 3-5m
- Food: Zooplankton
Manta Rays fertilize internally. The males, which are smaller than the females, chase her around the reef, forming long lines known as mating trains. These mating trains may last for days until the female selects one of the males to mate with her. The females are pregnant for 13 months and produce a single pup at the end of gestation. The average size newborn pup is 1.5-2m in disc width.
Feeding & Hunting
Manta rays have forward facing mouths which they use to filter plankton from the water. They use their cephalic lobes (fins) and huge mouths to force plankton-rich water over their gills as they swim. Manta rays often feed cooperatively to maximise their planktonic rewards through the least amount of effort.
Manta rays face natural threats from large warm water predators such as tiger sharks and killer whales, however the main threat faced by manta rays is man. Manta rays are often caught as bycatch, or harvested and sold for their meat, oily livers, and skin. In recent years there has been an increase in demand for the gill rakers of the manta to be dried and used in traditional Chinese medicine.
Conservation Status & International Protection
Manta rays are currently listed as ‘Near Threatened’ on the ICUN’s list of threatened species. Due to their low birth rates, slow growth and maturity rates, manta rays are particularly susceptible to habitat degradation and intensive fishing methods.
How can people help?
Each manta ray has a unique pattern of black spots on its white belly. These spots can be used just like a human fingerprint to identify individuals. The mantas are born with this pattern and they don’t change throughout their life. Photos of these markings, along with the date and location of where the manta was sighted, can greatly help researchers identify and study the mantas lives. If you have clear photos of these markings please contact www.mantatrust.org / IDtheManta@mantatrust.org
Other ways to help are to avoid touching or harassing the mantas whilst diving or snorkelling with them. Supporting charities that are dedicated to the conservation and protection of these amazing animals and their habitat will also help to safeguard their future.
The Manta Trust has complied to clearly lay out the key guidelines for interacting with manta rays, both at cleaning stations and during feeding events, either when snorkeling or on SCUBA. These documents can be downloaded directly from the Manta Trust’s Code of Conduct Public Resources section in PDF format here.
Best places in the world to see these creatures:
The Republic of Maldives has a resident population of around 5-7000 reef mantas, which are not fished or threatened through habitat destruction. As a result, the rich waters of the Maldives make this country one of the most renowned places to spot manta rays in large numbers. There are many other countries around the world where you can also see manta rays; e.g. Hawaii, Indonesia, Palau and Mexico.
Go on a Manta Trust Expedition to have the best Manta experience ever!
Scientist Profile: Guy Stevens
Description/Background of work
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