Thorntail stingray

Lore & Background

The thorntail stingray was originally described by Australian ichthyologist James Douglas Ogilby from four specimens collected off New South Wales during the 1898 scientific expedition of the trawler HMCS Thetis, after which the species was named. Its account was published in 1899 in the journal Memoirs of the Australian Museum. Molecular data from 2012 has confirmed that this species is a population of the broad stingray. This bottom-dweller inhabits soft-bottomed habitats such as lagoons, estuaries, and reefs, and is found off southern Africa, Australia, and New Zealand. It has a diamond-shaped pectoral fin disc, a very long tail with a fin fold underneath, and numerous stout, sharp thorns on its upper surface and tail. Uniformly dark above and light below, it can be differentiated from the similar short-tail stingray by its longer tail, presence of thorns, and absence of white dots on the disc. The diet of the thorntail stingray consists of benthic invertebrates and bony fishes. It is aplacental viviparous, with embryos sustained by histotroph. Large groups have been seen inside caves and beneath rocky arches off New Zealand, and it gathers in warm, shallow waters during summer, possibly for reproduction.

Reader's Guide

The thorntail stingray is significant as one of the largest stingrays in the world, reaching at least 4 m long and over 200 kg. Its venomous stinging spine can inflict a painful injury, though the species is reportedly unaggressive and approachable, and can be conditioned to accept being 'ridden' by divers. At Hamelin Bay, Western Australia, many thorntail stingrays gather with other rays to be hand-fed fish scraps, a site of growing tourist interest.

It is caught as bycatch in nets and on line gear, probably in low numbers, and recreational anglers sometimes hook it. From 1986 to 1997, New Zealand reported an average annual catch of 15 t for this species and the short-tail stingray combined. The impact of fishing on its population is unknown, leading the IUCN to list it as Data Deficient in 2008. In June 2018, the New Zealand Department of Conservation classified it as 'Not Threatened' with the qualifier 'Secure Overseas'. Its legacy includes being a notable component of reef and soft-bottom ecosystems, and a subject of both scientific study and ecotourism.

Did You Know?

• The thorntail stingray was named after the trawler HMCS Thetis, which collected the type specimens in 1898.
• It can reach a total length of at least 4 m (13 ft) and a weight of 214 kg (472 lb).
• Off New Zealand, both the thorntail stingray and the short-tail stingray regularly fall prey to local killer whales.
• A thorntail stingray with a width of 1.67 m and length of 2.35 m was caught and released off Warner Beach, South Africa in January 2020.