Southern stingray (Dasyatis americana)
|Spanish:||Raya Americana, Raya Chucho, Raya-látigo Americana|
|Size||Width: 152 cm (2)|
|Weight||up to 97 kg (3)|
Classified as Data Deficient (DD) on the IUCN Red List (1).
The southern stingray is adapted for life on the sea bed. The flattened, diamond-shaped body has sharp corners, making it more angular than the discs of other rays (3). The top of the body varies between olive brown and green in adults, dark grey in juveniles, whilst the underside is predominantly white (2) (3). The wing-like pectoral fins are used to propel the stingray across the ocean bottom, whilst the slender tail possesses a long, serrated and poisonous spine at the base, used for defence (4). These spines are not fatal to humans, but are incredibly painful if stepped on. The eyes are situated on top of the head of the southern stingray, along with small openings called spiracles. The location of the spiracles enables the stingray to take in water whilst lying on the seabed, or when partially buried in sediment. Water enters the spiracles and leaves through the gill openings, bypassing the mouth which is on the underside (3) (4).
The southern stingray occurs in the western Atlantic, from New Jersey to Florida, throughout the Gulf of Mexico, Bahamas, and the Greater and Lesser Antilles, and south to south-eastern Brazil (4). It is most abundant near Florida and the Bahamas (3).
Inhabits shallow coastal and estuarine waters, and buries itself in sandy bottoms, and occasionally muddy bottoms, to a depth of 53 metres (3) (4).
The southern stingray is an active swimmer that feeds primarily at night, on a diet of invertebrates and small fishes. It feeds by flapping the wing-like pectoral fins to disturb the sand and expose the prey (2). This bottom-dwelling species is often found singly or in pairs, except in the summer months when it migrates in schools to higher latitudes (4) (5).
Very little is known about the natural mating behaviour and reproductive biology of the southern stingray. Mating stingrays are rarely encountered in the wild; during one such rare occasion, the male was observed closely following the female, and then biting her before grasping the female’s pectoral fins with his mouth, and then copulating. It is thought that southern stingrays are polyandrous, as a female was observed mating with two males in quick succession (6). The southern stingray is ovoviviparous, a method of reproduction in which the egg develops within the female’s brood chamber. The pups hatch from their egg capsules inside the mother, and are born soon afterwards (5). In captivity, gestation lasted 135 to 226 days, after which a litter of two to ten young were born (7).
Fishing activities pose a potential threat to the southern stingray, either when caught accidentally along the east coast of the USA, or when deliberately targeted in parts of South America (1), where its flesh which is sold salted (4). The southern stingray is of considerable importance to ecotourism (4), and at well-known dive sites in the Cayman Islands (Stingray City and the Sandbar), large numbers of southern stingrays aggregate as a result of feeding by dive operators. There are concerns that this feeding, and the high levels of interaction with humans, may be having some negative impacts on the behaviour and ecology of the stingrays (8).
The World Conservation Union (IUCN), considered the southern stingray to be Data Deficient due to the lack of information regarding the impacts of fishing on this species. It is therefore important that harvesting of this species in South America is monitored, and that population surveys and monitoring are undertaken (1). The Guy Harvey Research Institute is undertaking a research project on the Cayman Island stingrays. Research on behaviour, reproduction, genetics and population characteristics is being undertaken, the results of which will help inform management and conservation plans for this charismatic species (8).
For further information on the conservation of sharks and rays see:
- Crustaceans: diverse group of arthropods (a phylum of animals with jointed limbs and a hard chitinous exoskeleton) characterised by the possession of two pairs of antennae, one pair of mandibles (parts of the mouthparts used for handling and processing food) and two pairs of maxillae (appendages used in eating, which are located behind the mandibles). Includes crabs, lobsters, shrimps, slaters, woodlice and barnacles.
- Invertebrates: animals with no backbone.
- Pectoral fins: the pair of fins that are found one on each side of the body just behind the gills. They are generally used for balancing and braking.
- Polyandrous: a mating system in which a female mates with several males during one breeding system.
IUCN Red List (June, 2007)
- Lieske, E. and Myers, R. (2001) Coral Reef Fishes: Indo-Pacific and Caribbean. HarperCollins Publishers, London.
Southern stingray Biological Profile, Ichthyology Department, Florida Museum of Natural History (August, 2007)
- Carpenter, K.E. (2002) The Living Marine Resources of the Western Central Atlantic, Volume 1. Food and Agriculture Organization of the United Nations, Rome.
MarineBio.org (August, 2007)
- Chapman, D.D., Corcorana, M.J., Harveya, G.M., Malanb, S. and Shivjia, M.S. (2003) Mating behaviour of southern stingrays, Dasyatis Americana (Dasyatidae). Environmental Biology of Fishes, 68: 241 - 245.
- Henningsen, A.D. (2000) Notes on reproduction in the southern stingray, Dasyatis Americana (Chondrichthyes: Dasyatidae), in a captive environment. Copeia, 2000: 826 - 828.
Guy Harvey Research Institute (August, 2007)