Stingrays

Common Names:
Short tail stingray.
                                             
Latin Name:
Dasyatis brevicaudata

Family:
Dasyatidae

Identification:
Rhomboid disc. Anterior disc margins almost straight with rounded tips. Dorsum smooth and dark brown to dark grey with a line of small white spots running down each side of body from level with the eyes towards the tail. Ventrum pale. Tail (usually with two stings) tapers quickly to a short thin whip. Tail shorter than disc with long ventral finfold.

Size:
Maximum disc width 2m.

Habitat:
Sand and rocky bottoms often near rocky reefs and continental drop offs. Intertidal to 476m. Observed mating in cave systems in New Zealand.

Abundance and distribution:
East and South Africa, Australia, and New Zealand. Reports from Thailand probably refer to the closely related Matsubara's Stingray (Dasyatis matsubarai) from Japan. Behavior: Moves into shallow water at flood tide to feed. Feeds on bony fishes, bivalves, squid, and crustaceans.

Reproduction:
Viviparous. In NZ males have been observed biting and holding onto the much larger females pectoral fin for hours at a time. During actual copulation the male flips upside down under the female and inserts one clasper. He then beats his pectoral fins up and down and in so doing moves his clasper in and out of the females cloaca. During maturation males have been observed nudging the female which may stimulate the birthing process.

Similar species:
Matsubara's Stingray (Dasyatis matsubarai) has a very similar appearance including the rows of white spots, but is only known from Japan and possibly Thailand. Reaction to divers: The short tail stingray moves away when approached but may ignore divers when concentrating on mating.

Diving logistics:
Although I have seen Short tail rays on almost every dive at Rottnest Island I found these big rays very unapproachable. A far better location to try would be the Poor Knights Marine Reserve off of New Zealand where hundreds of Shorttail stingrays Congregate to mate each summer.