Spotted Eagle Ray

Spotted Eagle Ray, Aetobatus narinari

The Spotted Eagle Ray, Aetobatus narinari, whose common Spanish name is chucho pinatado, is a species in the Eagle Ray or Myliobatidae Family, known collectively as águilas marinas in Mexico. Due to the wide global distribution of this species and varying reports related to its morphology, many scientists believe that this species will eventually be reclassified into four species. Globally, there are only three species in the genus Aetobatus, and this species is the only one found in Mexican waters it being one of the few species found in both the Atlantic and the Pacific.

The Spotted Eagle Rays have angular disc-shaped bodies that are approximately twice as wide as they are long. Dorsally they are covered with a dramatic pattern of small white, bluish-white, greenish, pearly, or yellow spots against a black, dark gray or brown background; their underside is off-white. The outer margins of their disc and tail are darker than the body. Their head and their projecting, elongated, narrow snout are set away from the disc and not joined with the pectoral fins. They have large spiracles that originate close to the origin of their pectoral fins. Their mouth has one series of flat, pavement-like plates of teeth. They have a single modest-sized dorsal fin at the base of their slender and whip-like tail. Their tail is two and a half to three times longer than the disc length and contains two to six long venomous spines with injecting barbs at the base which are used for self-defense. Their pectoral fins are long and pointed with curved tips and concave rear margins. Their pelvic fins are narrowly rounded. They do not have a caudal fin. Their skin is smooth and lacks denticles and thorns.

The Spotted Eagle Rays are an inshore species found in bays and around and within coral reefs at depths up to 270 feet. They reach a maximum disc width of 3.6 meters (11 feet 10 inches) and disc length of 2.5 meters (8 feet 2 inches) with total lengths of 5.0 meters (16 feet 5 inches) and weights of 230 kg (507 pounds). Males and females are of approximately equal sizes. They spend the majority of their time swimming either as solitary individuals or in large schools of up to several hundred individuals near the surface in open water. They are known to swim long distances and believed to be able to cross ocean basins. They are capable of leaping completely out of the water when pursued. They swim with a “flying” pattern utilizing their undulating pectoral fins. They have a high site fidelity and remain in or return to the same locations for long periods of time. They are highly social within their own species. They consume clams, octopi, oysters, squid, sea urchins, and various fish. In turn they are preyed upon by various large sharks that are known to follow the Spotted Eagle Rays during their birthing season, feeding on newborn pups. Reproduction occurs via ovoviviparity with internal fertilization. The embryos are initially fed on yolk then receive additional nourishment from the mother by indirect adsorption of uterine fluid enriched with mucus, fat, and protein. Litter sizes are small and consist of one to four pups that are born live as miniature adults being on average 26 cm (10 inches) in length; gestation periods last one year. Behavioral patterns including specific catch details, age, growth, longevity, movement patterns, reproduction, and range are generally poorly documented.

The Spotted Eagle Rays have a widespread distribution across the Indo-Pacific and eastern and western Atlantic in tropical and warm-temperate waters. In Mexican waters the Spotted Eagle Rays are found in all Mexican waters of the Atlantic and the Pacific with the exception that they are absent from Guerrero Negro northward along the central and northwest coasts of Baja. They are uncommon in Mexican waters of the Pacific and more common in waters of the western Caribbean.

The Spotted Eagle Ray from the Atlantic is most likely confused with the Southern Eagle Ray, Myliobatis goodei (dorsal fin well behind rear edges of pelvic fins) and the Spotted Eagle Ray from the Pacific is most likely confused with the Rough Eagle Ray, Pteromylaeus asperrimus (uniform red-brown color dorsally).

The Spotted Eagle Rays are caught by artisanal fishermen in various global locations with some regularity. They also show up occasionally as a bycatch of demersal shrimp trawls, longlines, and gill nets and are normally discarded with a high mortality rate. There is a small commercial fishery for the Spotted Eagle Ray, primarily in southeastern Asian markets with a new developing market in Australia. In some global areas they are fished as game fish. From a conservation perspective they are currently considered “near threatened” and their long term viability is of concern due to their population decline, inshore habitat, schooling behavior, accessibility via a wide variety of fishing gear including seines nets, harpoons, gill nets, purse seine nets, longlines, and bottom trawls, intense fishing pressure, a long reproduction cycle with small litter sizes, and a poorly documented unregulated fishery. They are considered a poor food fish and most catch is discarded or used in fishmeal or fish oil. They are a popular item in large public aquariums. In the Caribbean they can be observed with some frequency in and around reefs but are wary of divers and depart quickly when approached. Note: Rays of the genus Aetobatus have tails with a venomous spine. The Spotted Eagle Rays are potentially dangerous as they can inflict wounds with intense pain and slow recovery. Approximately 1,500 stings from stingrays are reported annually.

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Spotted Eagle Ray, Aetobatus narinari.  Fish provided by the commercial fishermen of the greater Los Cabos area, Baja California Sur, March 2008. Disc width: 58 cm (23 inches). Disc length: 33 cm (13 inches). Tail: a staggering 94 cm (37 inches).

Spotted Eagle Ray, Aetobatus narinari.  Underwater photo taken in coastal waters off Kailua-Kona, HI, October 2015. Disc width: 1.07 meters (3 feet 6 inches). Photo courtesy of Bob Hillis, Ivins, UT.