Porcupine Whipray, Porcupine ray.
A large stingray with a thick, oval disc that is equal to or very slightly narrower than long. Snout short, and obtusely angular or broadly rounded, with a small, protruding apical lobe at tip. Anterior margins of disc convex. Pectoral fin apices broadly rounded. Pelvic fins very short.
Eyes small and protuding. Snout length approximately 1.5-2x combined eye and spiracle length. Mouth wide with 3-5 short oral papillae. Lower jaw somewhat concave at symphysis. Labial furrows pronounced. Small, skirt-shaped nasal curtain with a long fringe on the posterior margin. Nostrils long and thin.
Disc densely covered in flattened plate-like denticles and large scattered thorns that are more concentrated near midline and dorsally on tail. Tail slender and short; length approximately equal to disc width. Tail tapers to caudal sting then slowly thins to tip. Caudal finfolds and stings absent.
Dorsum brownish, yellowish, or slate grey. Thorns often paler. Ventrum white, sometimes with a dusky margin. Tail beyond caudal sting black.
Maximum disc width 115cm. Disc width at birth unknown.
Tropical seas. In shallow sandy bays, coral reefs, sandy lagoons, mud flats, and mangroves. Intertiday to approximately 30m.
Widespread but patchy throughout the Indo-West Pacific. Absent from the Americas. Possibly also in the eastern Atlantic around west Africa.
The procupine whipray is presumably largely taken as bycatch in unregulated fisheries in nearshore waters. It has been recorded as a high value catch in Indonesian net fisheries (White et al. 2006). It appears to have disappeared or become extremely rare (compared to certain other batoids) in the batoid catches landed in Bangkok from the Gulf of Thailand in recent decades (Compagno and Cook, unpubl. data). This suggests probable local over-exploitation here and possibly also in the Bay of Bengal. Similar trends are likely to be occurring or will occur in other areas where batoids are taken in multi-species fisheries. Certainly, demersal fishery resources in the Gulf of Thailand and Southeast Asia have been severely depleted from historical levels (Stobutzki et al. 2006). Human modification and degradation of the ray’s habitat is also possibly occurring in some of the more highly populated and polluted coastal areas as a result of human influences. The loss of coastal habitats such as mangroves may be of particular concern for this species which is suspected to have highly localized habitat use (A. Chin, unpubl. data).
This species was occasionally taken in northern Australian trawl fisheries (Brewer et al. 2006). However, the introduction of turtle exclusion devices appears to have successfully excluded this species from continuing capture in trawl nets (Brewer et al. 2006). The Porcupine Ray is considered to be potentially one of the most vulnerable chondrichthyans to the impacts of climate change in northern Australia (Chin et al. 2010).
Chin, A. & Compagno, L.J.V. 2016. Urogymnus asperrimus. The IUCN Red List of Threatened Species 2016: e.T39413A68648645. https://dx.doi.org/10.2305/IUCN.UK.2016-1.RLTS.T39413A68648645.en. Downloaded on 26 February 2021.
Matrotrophic viviparity. Litter size unknown.
The porcupine ray feeds mostly on marine worms, crabs, and bivalves.
Feeds by ‘plowing’ through the substrate in search of buried prey species.
Reaction to divers
Quite easy to approach but will retreat if harassed.
The porcupine whipray is an uncommon ray that is rarely encountered throughout most of its range. A nursery has been identified in the coastal lagoons near Ningaloo Reef in Western Australia. Sightings also occur with some regularity in shallow bays in Mozambique and further north in east Africa.
Numerous other locations likely exist where this ray can be found. Systematic searches of shallow lagoons virtually anywhere in the warmer parts of the Indian Ocean are the best places to start.