Featured Elasmobranch – Pelagic Stingray

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Featured Elasmobranch – Pelagic Stingray

December 2010

Photo Credit: Andy Murch

Pelagic Stingray

 

Pteroplatytryon violacea (Bonaparte 1832)

 

Family Dasyatidae (Stingrays)

Identification: A stingray with a large, wedge-shaped disc, a broadly rounded snout and small eyes that do not protrude from the snout. The tail is whiplike and longer than the body with no caudal fin and one long serrated spine. Coloration is a uniform dark purple to grey throughout the body, slightly lighter on the ventral surface. The coloration is believed to camouflage them from potential predators.

Size: Males attain at least 59 cm disc width and females at least 80 cm disc width. In captivity some individuals have reached 96 cm disc width. Disc width at birth is 15–25 cm.

Distribution: It has a circumglobal distribution in tropical to warm temperate seas. It is known to migrate into higher latitudes with warmer water masses, but retreat as the waters cool. In the eastern North Pacific it has been reported as far north as British Columbia, but is generally considered uncommon north of Monterey Bay on the Central California coast.

Habitat: The Pelagic Stingray is the only stingray found in open ocean waters and inshore bays down to 238 m depth.  It does move inshore and offshore seasonally following their preferred water temperature of 18.8º C and above.

Biology:  This species is viviparous with a yolk sac placenta and has litters from 4–13. Males mature at two years old and 35–41 cm disc width and females mature at three years old and 40–50 cm disc width. Female gestation lasts for 2 to 3 months and females are known to be able to store sperm for at least one year. Males live to at least five or six years in captivity and females live up to nine years in captivity. The Pelagic Stingray is known to feed on a variety of pelagic prey including jellyfishes, crustaceans, squids and small bony fishes.

General interest: They are readily maintained in aquarium displays. They have no economic value, but are frequently taken as bycatch in commercial fisheries. Their long serrated spine is potentially dangerous to humans having caused at least two known human fatalities. The Great White Shark (Carcharodon carcharias) is a known predator of the Pelagic Stingray with other sharks and toothed whales being potential predators. There is some uncertainty about its taxonomic placement within the Family Dasyatidae. It is currently in its own genus, Pteroplaytyrgon but it has also place in the genus Dasyatis by some authors. The taxonomic status of this species is under investigation.

By Kelsey James

Graduate Student – Ichthyology

Pacific Shark Research Center

Moss Landing Marine Laboratories

8272 Moss Landing Rd

Moss Landing Rd, 95039

kjames@mlml.calstate.edu