Short-tail Stingray

Heavily built and characteristically smooth, the pectoral fin disc of the short-tail stingray has a rather angular, rhomboid shape and is slightly wider than long. The leading margins of the disc are very gently convex, and converge on a blunt, broadly triangular snout. The eyes are small and immediately followed by much larger spiracles. The widely spaced nostrils are long and narrow; between them is a short, skirt-shaped curtain of skin with a fringed posterior margin. The modestly sized mouth has an evenly arched lower jaw, prominent grooves at the corners, and five to seven papillae (nipple-like structures) on the floor. Additional, tiny papillae are scattered on the nasal curtain and outside the lower jaw. Short-tailed stingrays have between 45–55 densely arranged teeth, which are small, blunt, and conical. The teeth are arranged in a gridded, quincunx pattern, and have a flat, planar appearance. The pelvic fins are somewhat large and rounded at the tips. The tail is usually shorter than the disc and has one, sometimes two, serrated stinging spines on the upper surface, about halfway along its length. It is broad and flattened until the base of the sting; after, it tapers rapidly and a prominent ventral fin fold runs almost to the sting tip, as well as a low dorsal ridge. …

The short-tail stingray is common and widely distributed in the temperate waters of the Southern Hemisphere. Off southern Africa, it has been reported from Cape Town in South Africa to the mouth of the Zambezi River in Mozambique. Along the southern Australian coast, it is found from Shark Bay in Western Australia to Maroochydore in Queensland, including Tasmania. In New Zealand waters, it occurs off North Island and the Chatham Islands, and rarely off South Island and the Kermadec Islands. Records from northern Australia and Thailand likely represent misidentifications of pink whipray and pitted stingray, respectively. Over the past few decades, its range and numbers off southeastern Tasmania have grown, possibly as a result of climate change. Off southern Africa, the short-tail stingray is rare in shallow water and is most often found over offshore banks at a depth of 180 to 480 m (590 to 1,570 ft). However, off Australia and New Zealand, it was found from the intertidal zone to no deeper than 156 m (512 ft). Australian and New Zealand rays were most abundant in the shallows during the summer. A tracking study conducted on two New Zealand rays suggests that they shifted to deeper waters during the winter, but did not undertake long-distance migrations. …

The short-tail stingray is usually slow-moving, but can achieve sudden bursts of speed, flapping its pectoral fins with enough force to cavitate the water and create an audible "bang". Cavitation is when a liquid is pushed faster that it can react, causing a drop in pressure. It is known to form large seasonal aggregations; a well-known example occurs every summer (January to April) at the Poor Knights Islands off New Zealand, particularly under the rocky archways. In some areas, it moves with the rising tide into very shallow water. Individual rays tend to stay inside a relatively small home range with a radius of under 25 km (16 mi). Captive experiments have shown it capable of detecting magnetic fields via its electroreceptive ampullae of Lorenzini, which in nature may be employed for navigation. The short-tail stingray forages for food both during the day and at night. It feeds primarily on benthic bony fishes and invertebrates, such as molluscs and crustaceans. The lateral line system on its underside allows it to detect the minute water jets produced by buried bivalves and spoon worms, which are then extracted by suction; the excess water is expelled through the spiracles. Fishes and invertebrates from open water, including salps and hyperiid amphipods, are also eaten in significant quantities. …