Reef Stingray, Urobatis concentricus
The Reef Stingray, Urobatis concentricus, whose common Spanish name is raya redonda de arrecife, is a species in the American Round Stingray or Urotrygonidae Family, known collectively as raya redondas Americanas in Mexico. Globally, there are only six species in the genus Urobatis, four of which are found in Mexican waters, one in the Atlantic and three in the Pacific.
The Reef Stingrays have rounded flat bodies and vary in color being various shades of light gray with blackish lines or blotches and dark spots arranged in concentric rows on their discs giving them a “chain-like bullseye” appearance when viewed from above. Their discs are longer than they are deep and have fairly straight front side margins. Their snouts are rounded and their tails have two notable appendages that are approximately half the disc length. Their stingers are impressive (pictured below) being 2.5 cm (1 inch) in length. They feature a rounded caudal fin with very smooth skin that is devoid of denticles or thorns.
The Reef Stingrays reside over and within rubble bottoms adjacent to reefs at depths up to 395 feet. They reach a maximum total length of 48 cm (19 inches) with the discs have a maximum width of 28 cm (11 inches). They seek food by stirring the bottom sediment with their pectoral fins to dislodge small crustaceans, small fish, mussels, and worms on which they feed. The Reef Stingrays are a rare and poorly studied species and as such very limited information is available about their behavioral patterns.
In Mexican waters the Reef Stingrays are found from Cedros Island southward along the central and southwest coasts of Baja, throughout the Sea of Cortez, and along the coast of the mainland south to Acapulco.
The Reef Stingray can be confused with the Cortez Stingray, Urobatis maculatus (spots and blotches well away from the margin of the disc) and the Round Stingray, Urobatis halleri (dense dark brown spotting with circular markings).
When caught, the Reef Stingray is only retained by subsistence fishermen, and typically considered a “catch and release.”
Reef Stingray, Urobatis concentricus, juvenile. Fish provided by the commercial fishermen of the greater Los Cabos area, Baja California Sur, February 2014. Total Length: 13.5 cm (5.3 inches). Disc 8.4 cm (3.3 inches) x 8.3 cm (3.3 inches). Tail: 6.5 cm (2.6 inches).
Reef Stingray, Urobatis concentricus Underwater photo taken in coastal waters off Buena Vista, Baja California Sur, June 2017. Total Length: 25 cm (10 inches). Photo courtesy of Bob Hillis, Ivins, UT.
Reef Stingray, Urobatis concentricus. Fish caught from shore at Km 26, Cerro Colorado, Baja California Sur, July 2005. Total Length: 32 cm (13 inches). Identification confirmed by Dr. Ross Robertson, Smithsonian Tropical Research Institute, Panama.
Reef Stingray, Urobatis concentricus. Fish caught from shore at Los Barriles, Baja California Sur, January 2017. Total Length: 34 cm (13 inches). Catch and photo courtesy of Brad Murakami, Surrey, British Columbia, Canada.