Atlantic Devil Ray, Lesser Devil Ray, Atlantic Mobula Ray.
A relatively small mobula ray with a broad, kite-shaped disc and a wide subterminal mouth. Mouth width 0.11-0.14 x disc width. Upper and lower tooth bands cover approximately 50% of mouth width. Circular spiracles positioned laterally, below pectoral fin origin. Branchial filter plates separate on each gill arch.
Disc width 1.7-2x length. Anterior margins of pectoral fins straight or mildly convex. Pectoral fin apices acutely angular and somewhat falcate. Pelvic fins very small. One small falcate dorsal fin present at base of tail. Denticles widely spaced in adults; absent in juveniles. Tail long and whiplike; 1.5x disc length when intact. Caudal sting absent.
Dorsum greyish-brown or bluish-black, with a dark band across upper margin of mouth, and a second duskier (sometimes indistinct) band posterior to the first. Ventrum mostly white or light grey. Dorsal fin without a white tip.
Maximum disc width 133cm. Disc width at birth approximately 55cm.
Pelagic in tropical/subtropical seas. Usually found in coastal areas but sometimes offshore. Surface to approximately 100m.
Tropical/sub-tropical Atlantic. Western Atlantic from North Carolina to northern Patagonia including much of the Caribbean and Gulf of Mexico. Eastern Atlantic from Western Sahara to Angola.
Until recently, the eastern Atlantic population was thought to be a separate species (Mobula rochebrunei) but genetic evidence has shown this species to be a junior synonym of M. hypostoma.
Like most species of Mobula, the Atlantic Devilray has a very low reproductive output, with a late estimated age-at-maturity and low fecundity, and presumably a very low intrinsic rate of population increase. Increasing international trade in gill plates has led to the expansion of largely unregulated and unmonitored mobulid fisheries worldwide. Due mainly to its schooling behavior and its coastal near-shore distribution, this species is likely a bycatch component of many small-scale fisheries; this fishing effort has largely been unreported with catches often generalized as Mobula species. This species is widespread throughout the tropics and temperate waters of the Atlantic and depletions of the Atlantic Devilray are suspected in some parts of its range based on reduced sightings, and declines in catches and landings in recent years. It is now absent from many areas believed to be a part of its former geographic range and there have been few sightings in many countries, particularly in Brazil. Trends from genus-wide data where devilrays face heavy fishing pressure outside the range of the Atlantic Devilray, indicate significant declines of 51 to 94% over 10- to 15-year periods (~one generation length). The levels of fishing pressure resulting in these declines are similar to that likely in West Africa. Based on current and future levels of exploitation, declining trends, and a reduction in area of occupancy, it is suspected that this species has undergone a population reduction of 50–79% over the last three generations (38 years), with a further population reduction suspected over the next three generation lengths (2019–2057) due to ongoing demand for high-value products. The Atlantic Devilray is therefore assessed as Endangered A2cd+3d.
Marshall, A., Barreto, R., Carlson, J., Fernando, D., Fordham, S., Francis, M.P., Herman, K., Jabado, R.W., Liu, K.M., Rigby, C.L. & Romanov, E. 2019. Mobula hypostoma. The IUCN Red List of Threatened Species 2019: e.T126710128A896599. https://dx.doi.org/10.2305/IUCN.UK.2019-3.RLTS.T126710128A896599.en. Downloaded on 05 March 2021.
Aplacental viviparity. One pup per litter.
Diet mainly planktonic crustaceans and some small bony fishes.
An active swimmer that is usually found in small groups or very large aggregations.
Reaction to divers
Sometimes tolerant of snorkelers and divers when concentrating on feeding but otherwise rather difficult to approach.
Large schools of Atlantic devil rays sometimes show up north of Isla Mujeres, Mexico, during the June-September tuna spawning event that attracts hundreds of whale sharks and mantas. The mobulas sometimes intermingle with the sharks but more commonly remain in schooling formation a few meters below their gigantic cousins.
I have also seen Atlantic devil rays in the northern Gulf of Mexico while snorkeling off the beaches in Panama City, Florida. Mobulas migrate into warmer water in the winter so the best time to look for them in their northern range is probably mid to late summer.
Giant Devil Ray Distinguished by larger size, white-tipped dorsal fin, and presence of caudal sting. Sympatric in South America.
Chilean Devil Ray Distinguished by bony ridge along midline and thinner, highly falcate pectoral fin apices.
Bentfin Devil Ray Distinguished by central concavity along anterior margin of pectoral fins, and white-tipped dorsal fin.