Caribbean Manta Ray: Mobula cf. birostris

Family: Mobulidae
Common name(s)

Caribbean Manta Ray, Manta Ray.

NOTE: Physical characteristics  and recent genetic evidence suggest that the Caribbean manta ray may be a unique species but further research is needed before it can be scientifically described.

Identification

An extremely large ray with a vaguely kite-shaped disc and a large protruding head with a wide, terminal mouth. Disc width more than 2x length. Pectoral fins narrowly falcate, with convex anterior margins and concave posterior margins. Pectoral fin apices acutely pointed. Pelvic fins very small. One small dorsal fin present at base of tail; not falcate.
Head pronounced; extending well forward of pectoral fins. Slit-like spiracles posterior to eyes. Mouth very broad. Cephalic lobes long, broad, and highly flexible.
Band of vestigial teeth present on lower jaw.
Tail whiplike. One small caudal sting encased in a small calcified bulge near base of tail.

Colour

Markings are quite variable. Dorsum predominantly black, usually with varying white or grey shoulder markings that create a black T-shaped central space. The downstroke of the T narrows to a point, similar to a Tesla car logo. This differs from the standard T-shape on the centre line of an oceanic manta which has more of a wine glass shaped downstroke.
V-shaped marking anterior to tail, occasionally curving outward to reach pectoral fin apices. Mouth and inner surface of cephalic lobes usually white or dusky; outer/ventral surface white.
Ventrum mostly white, sometimes with dusky spots on 5th gill slits and a broad dusky margin along posterior edge of disc. Ventrum between gills and cloaca sometimes have irregular black spots and blotches that are unique to each animal.
Melanistic individuals are quite common; usually with an almost or completely black dorsal surface and either a black margined or solid black ventrum.

Size

Maximum disc width approximately 500cm. Disc width at birth unknown.

Habitat

Pelagic in tropical/subtropical seas. Found in coastal areas and in the open ocean. Maximum depth has not been established.

Distribution

Western tropical/sub-tropical Atlantic; North Carolina to Florida, Gulf of Mexico, and the Caribbean. Possibly south to Brazil and across the Atlantic to West Africa.

Conservation Status

NOT EVALUATED

The Caribbean Manta Ray has yet to be recognized as a valid species. Currently, it is grouped with the oceanic manta ray, which is listed as globally endangered. In Mexico, mantas are taken for food and for their gill rakers, so there is a likelihood of the Caribbean manta being similarly evaluated in the future.

Citation

Marshall, A., Barreto, R., Carlson, J., Fernando, D., Fordham, S., Francis, M.P., Derrick, D., Herman, K., Jabado, R.W., Liu, K.M., Rigby, C.L. & Romanov, E. 2020. Mobula birostrisThe IUCN Red List of Threatened Species 2020: e.T198921A68632946. https://dx.doi.org/10.2305/IUCN.UK.2020-3.RLTS.T198921A68632946.en. Downloaded on 28 February 2021.

Reproduction

Aplacental viviparity. Litter size unknown but M. birostris has 1 pup per litter with a maximum 4–7 pups during its estimated lifespan.

Diet

Diet mainly planktonic organisms and possibly small bony fishes.

Behavior

An active swimmer that may be solitary or in small or large aggregations. Between  June and September many Caribbean Mantas congregate in the lower Gulf of Mexico and adjacent Atlantic waters to feed on tuna eggs.

Reaction to divers

Fairly tolerant of snorkelers and divers when concentrating on feeding.

Diving logistics

YUCATAN PENINSULA, MEXICO.
Scores of Caribbean mantas often show up to join the huge aggregation of whale sharks that feasts on clouds of tuna eggs each summer north of Isla Mujeres. The mantas are not always in the same spot as the whale sharks but experienced captains can usually find the mantas. Later in the season (July-August) seems to be the best time.

2-3 hours north of Cancun in the mouth of the Gulf of Mexico, there is a manta cleaning station that the locals call Manta Valley. This spot is a bit hit or miss during whale shark season but is apparently much more reliable in the fall. As it is far from shore, this site is highly weather dependent.

I have also randomly seen mantas on the reefs of south Florida and on wrecks in the Outer Banks of North Carolina but the latter could be oceanic mantas that are thought to occur sympatrically.

Similar species

Oceanic Manta Ray Distinguished by differing shoulder markings.