January 2021 Elasmobranch of the Month: Southern Stingray
Author: Linda Weiss
Southern stingrays are deep, olive-green to dark brown on top while their undersides are cream to white with darker coloration on its edges. Sometimes, the topside of juveniles may be dark gray. This stingray species’ body is flat and diamond-shaped with a slightly pointed nose, wing-shaped pectoral fins and a tail. The tail can be almost twice the length of the body and has a venomous barb on the top, located approximately a third of the way down the tail. Two spiracles are located on top of their head. These openings allow them to breath when their gills, located underneath, are buried in the sea floor. Males grow in size up to .9 m (3 feet) from wingtip to wingtip, while females reach 1.5 m (5 feet) across. Maximum known weight is 97 kg (214 lbs). Multiple rows of teeth are contained in the stingray’s mouth, located on the underside of its head. The teeth near the corner of the mouth are smaller than the rest. The teeth of females and sub-adult males are rounded, tetragonally shaped. Mature males have rounded, cone-shaped cusps.
Image: Jillian Morris
Habitat and Distribution
The range of the Southern stingray is limited to the Western Atlantic and Gulf of Mexico, most commonly found in Florida and the Bahamas. This tropical and subtropical dweller is generally located in shallow coastal waters, swimming only a few feet above the ocean floor. Occasionally, they have been found at depths of nearly 61 m (200 feet).
Founder Jillian Morris with southern stingrays Credit: Duncan Brake
Southern stingrays forage the ocean floor, feeding on nearly anything edible they can find. In addition to using electroreception to detect prey, they also shoot water from their mouths or flap their fins to uncover prey hidden on the sea bed. Their diet is known to include worms, mollusks, crabs, shrimp, and fish.
Southern stingrays reproduce viviparously. Eggs are fertilized internally. The embryo begins development being nourished by a yolk sac, followed by uterine milk secreted by the mother. Gestation lasts 4-7 months, resulting in litter sizes ranging from 2-4 pups, with an average of 4.
Pups born in captivity range in length from 20-34 cm (7.9-13.4 inches) and weigh between 282-1128 g (.6 – 2.5 lbs). At birth, these stingrays are completely independent and the serrated tail barb is present.
The IUCN Red List of Threatened Species currently lists the Southern Stingray as Near Threatened, with a decreasing population trend.
Natural predators of the Southern stingray include sharks, especially hammerheads, and other larger fish. They do use their venomous barb in self-defense. They are removed from the ocean for use in the aquarium industry and are also killed as bycatch in the commercial and recreational fishing industries. Climate change and pollution from coastal development are also threats to this ocean animal.
National Marine Sanctuary Foundation
The IUCN Red List of Threatened Species
Carlson, J., Charvet, P., Blanco-Parra, MP, Briones Bell-lloch, A., Cardenosa, D., Derrick, D., Espinoza, E., Morales-Saldaña, J.M., Naranjo-Elizondo, B., Pacoureau, N., Schneider, E.V.C., Simpson, N.J., Pollom, R. & Dulvy, N.K. 2020. Hypanus americanus. The IUCN Red List of Threatened Species 2020: e.T181244884A104123787. https://dx.doi.org/10.2305/IUCN.UK.2020-3.RLTS.T181244884A104123787.en. Downloaded on 10 January 2021.