Round Stingray, Urobatis halleri
The Round Stingray, Urobatis halleri, whose common Spanish name is raya redonda común, 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 Round Stingrays have rounded flat bodies and vary in color from light brown to tan with the central portion of their discs usually featuring large circular markings superimposed on a spotted or vermiculated background. Their undersides are off white. Their discs are slightly longer than they are deep and have a fairly straight front side margin and a pointed snout. Their eyes and spiracles are on top of their heads and their mouths, nostrils, and gill slits are on their ventral sides. Their pectoral wings are rounded. Their tails are short and stout, equal to less than half the disc length, with a large stinger and a large rounded caudal fin. Their stingers are impressive (pictured below), varying in length from 2.5 cm (1.0 inch) to 3.8 cm (1.5 inch). They have very smooth skin that is devoid of denticles or thorns.
The Round Stingrays reside over and within sandy and muddy bottoms. They are occasionally found in rocky reef areas at depths up to 300 feet, however they are most abundant at depths of less than 50 feet and move to greater depths during cold-water episodes. During breeding season, they are found in greater numbers at estuary mouths and shallow bays. The Round Stingrays reach a maximum length of 58 cm (23 inches) with discs having a maximum width of 31 cm (12 inches), however most have disc diameters of less than 25.4 cm (10 inches). They can weigh up to 1.3 kg (3 lbs). 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. In turn they are preyed upon by the Northern Elephant Seal, Mirounga angustirostris and large fish such as the Giant Sea Bass, Stereolepsis gigas and the Leopard Shark, Triakis semifasciata. Their pups are born alive with disc widths ranging from 6.3 cm (2.5 inches) to 10.0 cm (3.9 inches); they are miniature adults that are independent at birth.
In Mexican waters the Round Stingrays are found in all waters of the Pacific.
The Round Stingray can be confused with the Cortez Stingray, Urobatis maculates (spots and blotches well away from the margin of the disc) and the Reef Stingray, Urobatis concentricus (chain-like dark markings on the back).
The Round Stingray is the most common ray found along the beaches of Southern California and Northern Baja generating numerous stingray injuries to waders and swimmers. From a fishing perspective, they are fairly abundant in certain locations but are only retained by subsistence fishermen, being considered by most to be a “catch and release.”
Round Stingray, Urobatis halleri. Fish provided by the commercial fishermen of the greater Los Cabos area, Baja California Sur, March 2012. Total Length: 38 cm (15 inches). Disc: 20 cm (7.9 inches) x 20 cm (7.9 inches). Tail: 17 cm (6.7 inches).
Round Stingray, Urobatis halleri. Fish caught from coastal waters off Mazatlán, Sinaloa, April 2013. Total Length: 58 cm (23 inches). Disc: 28 cm (11 inches) x 31 cm (12 inches). Catch and photo courtesy of George Brinkman, Guelph, Ontario, Canada.
Round Stingray, Urobatis halleri. Fish caught from coastal waters of Mission Bay, San Diego, California, December 2015. Length: 25 cm (10 inches). Catch, photo and identification courtesy of Ben Cantrell, Peoria, IL.
Round Stingray, Urobatis halleri. Fish caught from coastal waters off Catalina Island, California, September 2016. Catch, photo and identification courtesy of Chris Wheaton, Loreto, Baja California Sur.
Round Stingray, Urobatis halleri. Fish caught from shore at Los Barriles, Baja California Sur, January 2017. Total Length: 32 cm (13 inches). Catch and photo courtesy of Brad Murakami, Surrey, British Columbia, Canada.
Round Stingray, Urobatis halleri. Fish caught from shore at Los Barriles, Baja California Sur, December 2017. Total Length: 36 cm (14 inches). Catch and photo courtesy of Brad Murakami, Surrey, British Columbia, Canada.