Cortez Stingray, Urobatis maculatus
The Cortez Stingray, Urobatis maculatus, whose common Spanish name is raya redonda de Cortés, is a species in the family Urotrygonidae, the American Round Stingrays, known as raya redondas Americanas in Mexico. Globally, there are only six species in the genus Urobatis, of which four are found in Mexican waters, one in the Atlantic and three in the Pacific.
The Cortez Stingrays have rounded flat bodies and vary in color from brown to brownish gray with irregular, variably-sized, and widely-spaced dark brown to black blotches and spots. Their undersides are off white. Their discs are approximately 1.3 times longer than they are deep and have fairly straight front margins and a bluntly angular 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 or less than the disc length, and feature a large stinger and a large rounded caudal fin. These stingers are impressive, 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 Cortez 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. The Cortez Stingray has a limited distribution being found in the Pacific from Guerrero Negro south along the west coast of Baja and throughout the Sea of Cortez.
The Cortez Stingrays reach a maximum length of 42 cm (17 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 seek food by stirring the bottom sediment with their pectoral fins to dislodge small crustaceans, small fish, mussels, and worms on which they feed. Their pups are born alive and are miniature adults that are independent at birth. They are a rare and poorly studied species and as such very limited information is available about their behavioral patterns.
The Cortez Stingray can be confused with the Blotched Stingray, Urotrygon chilensis (gray to gray brown coloration with no spots), the Reef Stingray, Urobatis concentricus (dark spots arranged in circles), and the Round Stingray, Urobatis halleri (dense dark brown spots with circular markings).
The Cortez Stingray are fairly abundant in certain locations at certain times of the year. From a fishing perspective, they are only retained by subsistence fishermen and typically considered a “catch and release.”