The reef manta ray (''Mobula alfredi'') is a species of

ray Ray may refer to: Fish * Ray (fish), any cartilaginous fish of the superorder Batoidea * Ray (fish fin anatomy), a bony or horny spine on a fin Science and mathematics * Ray (geometry), half of a line proceeding from an initial point * Ray (g ...

in the

family Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its members and of society. Idea ...

Mobulidae, one of the largest rays in the world. Among generally recognized species, it is the second-largest species of ray, only surpassed by the giant oceanic manta ray (a currently unrecognized species from the Caribbean region also appears to be larger than the reef manta ray). The species was described in 1868 by Gerard Krefft, the director of the Australian Museum. He named it ''M. alfredi'' in honor of Alfred, Duke of Edinburgh, the first member of the British royal family to visit Australia. It was originally described as part of the genus ''Manta'' but in 2017 was changed, along with the rest of the mantas, to be included as part of the genus ''Mobula''. Reef manta rays are typically in disc width, with a maximum size of about . For a long time included in '' M. birostris'', the status of the reef manta ray as a separate species was only confirmed in 2009. The reef manta ray is found widely in the tropical and subtropical

Indo-Pacific The Indo-Pacific is a vast biogeographic region of Earth. In a narrow sense, sometimes known as the Indo-West Pacific or Indo-Pacific Asia, it comprises the tropical waters of the Indian Ocean, the western and central Pacific Ocean, and the ...

, but with a few records from the tropical East Atlantic and none from the West Atlantic or East Pacific. Compared to the giant oceanic manta ray, the reef manta ray tends to be found in shallower, more coastal habitats, but local migrations are sometimes reported. ''

Mobula birostris The giant oceanic manta ray, giant manta ray, or oceanic manta ray (''Mobula birostris'') is a species of ray in the family Mobulidae, and the largest type of ray in the world. It is circumglobal and is typically found in tropical and subtropica ...

'' is similar in appearance to ''Mobula alfredi'' and the two species may be confused as their distribution overlaps. However, there are distinguishing features.

Description

The reef manta ray can grow to a disc size of up to but average size commonly observed is 3 to . It is dorsoventrally flattened and has large, triangular

pectoral fins Fins are distinctive anatomical features composed of bony spines or rays protruding from the body of a fish. They are covered with skin and joined together either in a webbed fashion, as seen in most bony fish, or similar to a flipper, as s ...

on either side of the disc. At the front, it has a pair of cephalic fins which are forward extensions of the

. These can be rolled up in a spiral for swimming or can be flared out to channel water into the large, forward-pointing, rectangular mouth when the animal is feeding. The eyes and the spiracles are on the side of the head behind the cephalic fins, and the five gill slits are on the

ventral Standard anatomical terms of location are used to unambiguously describe the anatomy of animals, including humans. The terms, typically derived from Latin or Greek roots, describe something in its standard anatomical position. This position prov ...

(under) surface. It has a small dorsal fin and the tail is long and whip-like. The manta ray does not have a spiny tail as do the closely related devil rays (''Mobula'' spp.). The color of the dorsal side is dark black to midnight blue with scattered whitish and greyish areas on top head. The ventral surface is white, sometimes with dark spots and blotches. The markings can often be used to recognise individual fish. ''Mobula alfredi'' is similar in appearance to ''

'' and the two species may be confused as their distribution overlaps. However, there are distinguishing features.

Physical distinctions between oceanic manta ray and reef manta ray

The first difference could be the size because the giant oceanic manta ray is bigger than the reef manta ray, on average versus on average. However, if the observed rays are young, their size can easily bring confusion. Only the color pattern remains a fast and effective way to distinguish them. The reef manta ray has a dark dorsal side with usually two lighter areas on top of the head, looking like a nuanced gradient of its dark dominating back coloration and whitish to greyish, the longitudinal separation between these two lighter areas forms a kind of “Y”. While for the oceanic manta ray, the dorsal surface is deep dark and the two white areas are well marked without gradient effect. The line of separation between these two white areas form meanwhile a "T". Difference can also been made by their ventral coloration, the reef manta ray has a white belly with often spots between the branchial gill slits and other spots spread across trailing edge of

and abdominal region. The oceanic manta ray has also a white ventral coloration with spots clustered around lower region of its abdomen. Its cephalic fins, inside of its mouth and its gill slits are often black.

Distribution and habitat

The reef manta ray has a widespread distribution in tropical and subtropical parts of the

, with few records from the warm East Atlantic and none in the West Atlantic or East Pacific. It can be observed in several often-visited regions such as

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, Fiji,

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Bali Bali () is a province of Indonesia and the westernmost of the Lesser Sunda Islands. East of Java and west of Lombok, the province includes the island of Bali and a few smaller neighbouring islands, notably Nusa Penida, Nusa Lembongan, and Nu ...

, Komodo,

Maldives The Maldives, officially the Republic of Maldives,, ) and historically known as the Maldive Islands, is a country and archipelagic state in South Asia in the Indian Ocean. The Maldives is southwest of Sri Lanka and India, about from the A ...

Mozambique Mozambique (), officially the Republic of Mozambique ( pt, Moçambique or , ; ny, Mozambiki; sw, Msumbiji; ts, Muzambhiki), is a country located in southeastern Africa bordered by the Indian Ocean to the east, Tanzania to the north, Mala ...

, Australia and the Philippines. It is primarily found in coastal regions. Reef manta rays live in a more or less identical wide area with the possibility of short migration to follow the

zooplankton Zooplankton are the animal component of the planktonic community ("zoo" comes from the Greek word for ''animal''). Plankton are aquatic organisms that are unable to swim effectively against currents, and consequently drift or are carried along by ...

. They therefore have a relatively sedentary behavior with precise areas for cleaning and feeding still within close proximity of coasts, reefs or islands.

Biology

The reef manta ray has a

pelagic The pelagic zone consists of the water column of the open ocean, and can be further divided into regions by depth (as illustrated on the right). The word ''pelagic'' is derived . The pelagic zone can be thought of as an imaginary cylinder or w ...

lifestyle and feeds by filtering sea water in order to catch

. Research indicates that mantas may live to at least 50 years old. Like the Oceanic manta ray, it has the largest

brain The brain is an organ that serves as the center of the nervous system in all vertebrate and most invertebrate animals. It consists of nervous tissue and is typically located in the head ( cephalization), usually near organs for special ...

weight and ratio among cold blooded fish. Also, reef manta rays have been confirmed to form social communities in specific populations. In New Caledonia, there are records of diving up to 672m in search of

food Food is any substance consumed by an organism for nutritional support. Food is usually of plant, animal, or fungal origin, and contains essential nutrients, such as carbohydrates, fats, proteins, vitamins, or minerals. The substance is ...

. It is believed that this allows Reef manta ray to act in the cold deep waters with certain Rete mirabile in the pectoral fins that can act as countercurrent heat. The reef manta ray, as the oceanic manta ray, is

ovoviviparous Ovoviviparity, ovovivipary, ovivipary, or aplacental viviparity is a term used as a "bridging" form of reproduction between egg-laying oviparous and live-bearing viviparous reproduction. Ovoviviparous animals possess embryos that develop insi ...

. After mating, the fertilized eggs develop within the female's

oviduct The oviduct in mammals, is the passageway from an ovary. In human females this is more usually known as the Fallopian tube or uterine tube. The eggs travel along the oviduct. These eggs will either be fertilized by spermatozoa to become a zygote, ...

. At first, they are enclosed in an egg case and the developing

embryo An embryo is an initial stage of development of a multicellular organism. In organisms that reproduce sexually, embryonic development is the part of the life cycle that begins just after fertilization of the female egg cell by the male sperm ...

s feeds on the

yolk Among animals which produce eggs, the yolk (; also known as the vitellus) is the nutrient-bearing portion of the egg whose primary function is to supply food for the development of the embryo. Some types of egg contain no yolk, for example bec ...

. After the egg hatches, the pup remains in the oviduct and receives nourishment from a milky secretion. As it does not have a

placenta The placenta is a temporary embryonic and later fetal organ (anatomy), organ that begins embryonic development, developing from the blastocyst shortly after implantation (embryology), implantation. It plays critical roles in facilitating nutrien ...

l connection with its mother, the pup relies on

buccal pumping Buccal pumping is "breathing with one's cheeks": a method of ventilation used in respiration in which the animal moves the floor of its mouth in a rhythmic manner that is externally apparent.Brainerd, E. L. (1999). New perspectives on the evolutio ...

to obtain oxygen. The brood size is usually one but occasionally two embryos develop simultaneously. The

gestation period In mammals, pregnancy is the period of reproduction during which a female carries one or more live offspring from implantation in the uterus through gestation. It begins when a fertilized zygote implants in the female's uterus, and ends once ...

is thought to be 12–13 months. When fully developed, the pup is in disc width, weighs and resembles an adult. It is expelled from the oviduct, usually near the coast, and it remains in a shallow-water environment for a few years while it grows. The disc width of the largest pup born at Okinawa Churaumi Aquarium was about .

Status and threats

Natural predation

Because of its large size and velocity in case of danger ( escape speed), the reef manta ray has very few natural predators which can be fatal to it. Only big sharks, for example the

tiger shark The tiger shark (''Galeocerdo cuvier'') is a species of requiem shark and the last extant member of the family Galeocerdonidae. It is a large macropredator, capable of attaining a length over . Populations are found in many tropical and temper ...

(''Galeocerdo cuvier''), the great hammerhead shark (''Sphyrna mokarran'') or the

bull shark The bull shark (''Carcharhinus leucas''), also known as the Zambezi shark (informally zambi) in Africa and Lake Nicaragua shark in Nicaragua, is a species of requiem shark commonly found worldwide in warm, shallow waters along coasts and in ri ...

(''Carcharhinus leucas''), and also the

false killer whale The false killer whale (''Pseudorca crassidens'') is a species of oceanic dolphin that is the only extant representative of the genus '' Pseudorca''. It is found in oceans worldwide but mainly in tropical regions. It was first described in 18 ...

(''Pseudorca crassidens'') and the

killer whale The orca or killer whale (''Orcinus orca'') is a toothed whale belonging to the oceanic dolphin family, of which it is the largest member. It is the only extant species in the genus '' Orcinus'' and is recognizable by its black-and-white ...

(''Orcinus orca'') are known to kill and eat mantas. The reef manta ray may escape an attack, leaving it with a part of the wing missing. The reef manta ray is considered to be

vulnerable Vulnerable may refer to: General * Vulnerability * Vulnerability (computing) * Vulnerable adult * Vulnerable species Music Albums * ''Vulnerable'' (Marvin Gaye album), 1997 * ''Vulnerable'' (Tricky album), 2003 * ''Vulnerable'' (The Used album) ...

by the IUCN in its

Red List of Threatened Species The International Union for Conservation of Nature (IUCN) Red List of Threatened Species, also known as the IUCN Red List or Red Data Book, founded in 1964, is the world's most comprehensive inventory of the global conservation status of biolog ...

because their population decreased drastically over the last twenty years due to overfishing. Whatever the type of fishing (artisanal, targeted or bycatch), the impact on a population which has a low fecundity rate, a long gestation period with mainly one pup at a time, and a late sexual maturity can only be seriously detrimental as the species cannot compensate for the losses over several decades. In recent years, fishing for manta rays has been significantly boosted by prices of their gill rakers on the market for traditional Chinese medicine. Pseudo-medicinal virtues assigned to them without proven scientific basis and a clever marketing strategy generate significant demand. File:Manta alfredi at a ‘cleaning station’ - journal.pone.0046170.g002B.png, ''M. alfredi '' at a cleaning station, maintaining a near-stationary position on top a coral patch for several minutes while being cleaned by

cleaner fish Cleaner fish are fish that show a specialist feeding strategy by providing a service to other species, referred to as clients, by removing dead skin, ectoparasites, and infected tissue from the surface or gill chambers. This example of cleaning ...

Jaine FRA, LIE Couturier, SJ Weeks, KA Townsend, MB Bennett, K Fiora and AJ Richardson (201
"When Giants Turn Up: Sighting Trends, Environmental Influences and Habitat Use of the Manta Ray Manta alfredi at a Coral Reef"
''PLoS ONE'', e46170. File:Manta alfredi cruising - journal.pone.0046170.g002A.png, ''M. alfredi '' cruising (swimming with cephalic lobes rolled and mouth closed) Manta alfredi ram feeding.png, Foraging ''M. alfredi ''

ram feeding Aquatic feeding mechanisms face a special difficulty as compared to feeding on land, because the density of water is about the same as that of the prey, so the prey tends to be pushed away when the mouth is closed. This problem was first identifi ...

, swimming against the tidal current with its mouth open and sieving zooplankton from the water File:Female scuba diver swims with a young male Manta ray - Kona district, Hawaii.jpg, Juvenile ''M. alfredi '' with a diver (

Kona Kona or KONA may refer to: People *Kona (surname) * Dilshad Nahar Kona, Bangladeshi singer also known as Kona Television * ''Kona'' (TV series), a Kenyan telenovela that premiered in 2013 Locations * Kona, Kentucky * Kona, North Carolina * Kon ...

) File:Reef manta at Manta Alley.JPG, ''M. alfredi '' from Komodo,

Indonesia Indonesia, officially the Republic of Indonesia, is a country in Southeast Asia and Oceania between the Indian and Pacific oceans. It consists of over 17,000 islands, including Sumatra, Java, Sulawesi, and parts of Borneo and New Guine ...

File:Manta ray from Yap.jpg, ''M. alfredi '' from Yap,

File:Manta Bali.jpg, ''M. alfredi '' from

References

External links

* {{Taxonbar, from=Q1620164 Fish described in 1868 Fish of Australia Fish of Oceania Fish of the Indian Ocean Fish of the Pacific Ocean Marine fish of Africa Marine fish of Southeast Asia Myliobatidae Vulnerable biota of Africa Vulnerable fauna of Asia Vulnerable fauna of Oceania Vulnerable fish