Distribution:
Found in warm, temperate, tropical, and subtropical
waters worldwide. Often travels long distances
across pelagic zones. Seasonal migrations are
sometimes associated with changes in plankton density.
Ecosystem:
Commonly observed near coral reefs, cleaning
stations, coastal bays, and offshore seamounts.
Feeding Habits:
Filter feeders that consume microscopic
plankton, small fish, and crustaceans
Taxonomy:
Class: Chondrichthyes
Family: Mobulidae
Overview and Physical Characteristics
Manta rays are among the largest rays in the ocean. There are two recognized species of manta ray: the giant oceanic manta ray (Mobula birostris) and the reef manta ray (Mobula alfredi). The giant oceanic manta ray can reach a wingspan of up to 7 meters (23 feet) and weigh up to 2,000 kilograms (4,400 pounds). Their flattened bodies have large, wing-like pectoral fins and two distinct horn-like cephalic fins near the mouth. These fins help direct food into their mouths during feeding. Unlike some rays, mantas do not have a stinger on their tail.
Habitats and Distribution
Manta rays are found in warm, temperate, tropical, and subtropical waters worldwide. They are commonly observed near coral reefs, cleaning stations, coastal bays, and offshore seamounts. Seasonal migrations are sometimes associated with changes in plankton density. Giant oceanic manta rays roam across open oceans, often traveling vast distances. While they spend much of their time closer to the surface, manta rays are known to dive as deep as 1,000 meters (3,280 feet).
Ecosystem
Giant oceanic manta rays are filter feeders that play a crucial role in marine ecosystems. By consuming vast quantities of plankton, they help regulate plankton populations and nutrient cycling. They also contribute to coral reef health by participating in symbiotic relationships at cleaning stations, where cleaner fish remove parasites from their bodies.
Although not considered apex predators, manta rays are an important mid-level species that help maintain ecological balance. Their large size and gentle nature make them important ecological symbols in marine conservation.
Feeding Habits and Predation
Manta rays are filter feeders, using their gill rakers to strain microscopic plankton, small fish, and crustaceans from the water. They often feed while swimming in slow, graceful loops or barrel rolls, funneling water through their mouths with the help of cephalic fins.
Predators of manta rays include large sharks, orcas, and, in some regions, humans. However, due to their size and agility, adult mantas have few natural predators. Their biggest threat comes from targeted and bycatch fishing.
Behavior and Reproduction
Manta rays are generally solitary but do exhibit complex social behavior. They are known to aggregate in large numbers (up to 100 individuals) in many areas (e.g., Mexico, Mozambique, Maldives, and Hawaii) for courtship, breeding, and to visit cleaning stations. Manta rays are capable swimmers and can travel long distances, although their movements are still being studied.
Mating involves an elaborate courtship “train” where several males pursue a single female. Reproduction is ovoviviparous: embryos develop inside eggs that remain within the mother until they hatch. Females give birth to a single pup after a gestation period of about a year. The pup is born live and independent, typically measuring about 1.2 to 1.5 meters (4 to 5 feet) across. Their low reproductive rates (giving birth every two to five years) make manta ray populations vulnerable to overexploitation.
Visual System and Communication
Manta rays possess some of the largest brains among fish, and their advanced visual system is a key adaptation. Their eyes are positioned laterally, giving them a wide field of view. They can detect contrast and motion very effectively, which aids in navigation, predator awareness, and social interactions. Manta rays do not communicate through sound; they use body language – flapping, rolling, or breaching during mating displays, feeding, or social bonding.
Conservation Status
The giant oceanic manta ray is listed as threatened on the Endangered Species List. Threats include bycatch in commercial fisheries and habitat degradation from coastal development and pollution.
Fun Fact
Manta rays are capable of breaching, or leaping entirely out of the water. Scientists aren’t sure exactly why they do this, but theories include mating displays, parasite removal, and social communication.
BOEM Studies:
This study used aerial surveys and satellite and acoustic telemetry to track the movements of oceanic manta rays off the U.S. East Coast. Through fieldwork and aerial surveys, BOEM was able to enhance its understanding of the animals’ migration and range, which will help inform the bureau’s future marine mineral extraction mitigation policies to reduce potential impacts to this threatened species.
Watch researchers in action with this video from the Georgia Aquarium, which includes fieldwork footage and interviews with project partners, including BOEM scientists.
--BOEM--
The Department of the Interior’s Bureau of Ocean Energy Management (BOEM) manages development of U.S. Outer Continental Shelf (OCS) energy, mineral, and geological resources in an environmentally and economically responsible way.