Red stingray

Lore & Background

The original description of the red stingray was published by Johannes Müller and Friedrich Henle in their 1841 Systematische Beschreibung der Plagiostomen under the name Trygon akajei, based on an earlier account of 'Pastinaca akajei' by Heinrich Bürger. A lectotype for this species was designated by Marinus Boeseman in 1947. Other common names include brown stingray, estuary stingaree, Japanese red stingray, Japanese stingray, red skate, whip ray, whip stingray, and yellow stingray.

The red stingray may be endemic to the northwestern Pacific Ocean; it is found throughout Japanese coastal waters from Hokkaidō to Okinawa, and also occurs off Korea, mainland China and Taiwan. This species has been reported from as far as Thailand, the Philippines, Fiji, and Tuvalu, though whether these records truly represent D. akajei has yet to be determined. It is commonly encountered in sandy areas close to shore and in bays at a depth of 10 m (33 ft) or more, but also inhabits muddy flats, coral reefs, and estuaries.

The red stingray has a diamond-shaped pectoral fin disc wider than long, with nearly straight front margins converging to a triangular snout. The small eyes are slightly elevated, and followed by spiracles that are almost twice as large. The tail is whip-like and measures 1–1.5 times as long as the disc is wide. A long, serrated spine originates in the first third of the tail, and is followed by a low dorsal keel and a ventral fin fold. This species is plain brown above, often with yellow or orange coloring before the eyes, behind the spiracles, around the disc margin, and laterally on the tail in front of the spine. The underside is white with bright orange-red patches.

Reader's Guide

The red stingray plays a key ecological role as an apex predator in its environment, feeding mainly on crustaceans and bony fishes. In Tokyo Bay, important crustacean prey species are Crangon affinis for males, Oratosquilla ijimai for females, and Anisomysis ijimai for juveniles; the most important fish prey species is Sardinops melanostictus, followed by Conger myriaster. Reproduction is aplacental viviparous, with females giving birth to 1 or up to 10 pups at a time. Males mature sexually at a disc width of 35–40 cm, and females at a disc width of 50–55 cm.

The red stingray is valued as food in Japan, especially in the Tokyo Bay area where it is consumed in autumn and winter; it may be prepared hard boiled, with miso soup, or as kamaboko. Large numbers are caught as bycatch and brought to market, which has seemingly led to a population decline in this unprolific species. Annual catches reported by Japanese fisheries have steadily declined from 20,000 tons in 1950 to varying between 3,959 and 5,388 tons from 1997 to 2004. Such apparent depletion, coupled with continuing heavy fishing pressure and a slow reproductive rate, have led the International Union for Conservation of Nature (IUCN) to assess this species as Near Threatened. The venomous tail spine is potentially injurious to humans; the Ainu once used the dried tail spine, with the toxic sheath intact, as a weapon.

Did You Know?

• The red stingray gains its common name from its bright orange-red underside.
• The Ainu once used the dried tail spine of the red stingray, with the toxic sheath intact, as a weapon.
• The Mekong freshwater stingray (D. laosensis) also has orange ventral coloration but differs in disc shape, denticle coverage, and dorsal coloration.

Physical Form and Scale

Among the largest stingrays on Earth, the short-tail stingray commands attention with its massive, heavily built frame. This species can stretch to at least 2.1 meters across its pectoral disc, reach 4.3 meters in total length, and weigh up to 350 kilograms, with reliable New Zealand observers reporting individuals nearly 3 meters wide. Its disc takes on a distinctly angular, rhomboid shape, slightly wider than it is long, with gently convex leading edges that converge on a blunt, broadly triangular snout. What sets this ray apart visually is its remarkably smooth surface—adults lack the dermal denticles that cover most other ray species, giving the body a sleek, almost polished appearance. The dorsal coloration ranges from plain grayish-brown to dark grey or black, sometimes punctuated by rows of white spots along each wing. A striking feature is the line of white pores flanking the head on either side. The tail, typically shorter than the disc itself, is thick at the base and armed with one or two serrated stinging spines, a midline row of large backward-pointing thorns, and smaller conical thorns extending to the tip. Albino individuals have also been documented.

Geographic Range and Habitat Preferences

Native to the temperate waters of the Southern Hemisphere, the short-tail stingray occupies a broad geographic sweep. Along the southern African coast, it ranges from Cape Town in South Africa northward to the Zambezi River mouth in Mozambique, typically inhabiting offshore banks at depths between 180 and 480 meters. In Australian waters, its range stretches from Shark Bay in Western Australia all the way to Maroochydore in Queensland, including the island state of Tasmania. New Zealand hosts populations off the North Island and the Chatham Islands, with rarer sightings near the South Island and Kermadec Islands. Unlike many marine species, this ray tends to remain within a relatively confined home range year-round, favoring deeper waters during the colder months without undertaking long migrations. It is predominantly a bottom-dweller, encountered across diverse habitats from sheltered estuaries to reefs, yet it also ventures freely into open water. Notably, over recent decades, both the range and numbers of this species off southeastern Tasmania have expanded, a trend potentially linked to climate change.

Reproduction, Aggregation, and Defense

Reproduction in the short-tail stingray follows an aplacental viviparous strategy, meaning the mother carries her young to term without a placental connection. Instead, developing embryos are nourished by histotroph, a nutrient-rich fluid sometimes called uterine milk, secreted by the mother. A typical litter contains between six and ten pups, though litters of up to fifteen have been recorded. Mature females are roughly a third larger than their male counterparts. Perhaps the most remarkable aspect of this species' social life is its seasonal aggregation behavior. At specific locations, large groups of rays gather together, with the Poor Knight Islands off New Zealand serving as a well-documented example during summer months. Both mating and birthing events have been observed within these gatherings, suggesting these aggregations play a central role in the species' reproductive cycle. Despite their formidable size and venomous stinging apparatus, these rays are not considered aggressive toward humans, though their long, venomous sting is capable of inflicting a potentially lethal wound.

Taxonomic History and Common Names

The scientific identity of the short-tail stingray has shifted several times over nearly two centuries. The species was first formally described in 1875 by Frederick Hutton, curator of the Otago Museum in New Zealand, who examined a female specimen measuring 1.2 meters across, caught off Dunedin. Hutton published his account in the Annals and Magazine of Natural History, naming it Trygon brevicaudata—a combination of the Latin words for short and tail. For many years afterward, the ray was reassigned to the genus Dasyatis. However, a 2016 taxonomic review by Last and colleagues resurrected the genus Bathytoshia, placing this species alongside the broad stingray and roughtail stingray. That same year, molecular phylogenetic analysis prompted researchers to absorb two previously separate species, Dasyatis matsubarai and Dasyatis multispinosa, into the short-tail stingray. The animal itself has accumulated a remarkable array of common names, including giant black ray, Schreiners ray, short-tailed stingaree, and smooth short-tailed stingray, reflecting its broad geographic range and the many communities that have encountered it.