Tortonese’s Stingray: Dasyatis tortonesei

Family: Dasyatidae
Common name(s)

Tortonese’s Stingray.

Identification

A medium sized stingray with a kite-shaped disc that is slightly wider than long; disc width approximately 1.2-1.4 x length. Snout obtusely angular with a small, slightly protruding tip. Anterior margins of disc somewhat convex. Pectoral fin apexes narrowly rounded or angular. Pelvic fins narrow; posterior margins considerably posterior to pectoral disc margin. Pelvic fin apexes rounded.
Eyes medium sized and slightly protruding. Snout length 1.6-1.9 x combined eye and spiracle length.
Mouth usually contains 3 filamentous oral papillae. Deep labial furrows around mouth. Lower jaw sinuous; mostly convex but concave at symphysis. Small, skirt shaped nasal curtain with a heavily fringed margin. Nostrils oval shaped.
Disc lacks dermal denticles in young. Larger adults have some denticles and thorns on disc and midline thorns on tail anterior to sting. Tail broad and depressed at base, tapering gently to tail sting, then filamentous to tip. Tail length relatively short; 1.2-1.4 x disc width. Long, deep dorsal and ventral finfolds. One very long tail sting is usually present.

Colour

Dorsum golden brown. Disc margin and around eyes often dusky. Midline dusky; darkeing towards dorsal surface of tail. Side of tail pale. Ventrum white with a dusky disc margin. Tail beyond sting and fin folds dark.

Size

Maximum disc width 84cm. Disc width at birth 15-16cm.

Habitat

Sub-tropical seas. On soft substrates, sometimes adjacent to reefs. From shallow estuaries to at least 100m.

Distribution

Eastern Atlantic Ocean and western Mediterranean Sea. Found from southern France to Mauritania, and eastward to  Greece and Libya.

Conservation Status

NOT EVALUATED

Tortonese’s stingray is a recently resurrected species that is still grouped with the common stingray D. pastinaca by the IUCN. The following information related to both species but D. tortonesei does not occur north of southern France:

This species is taken as bycatch and is sometimes targeted in semi-industrial, small-scale and commercial bottom trawl, gillnet, beach seine, bottom longline and trammelnet fisheries. Commercial fishermen often cut off the tails of stingrays following capture and prior to discarding, although it is unclear as to how this affects discard survival (Notarbartolo and Bianchi 1998). Little data are available on catches as a result of discarding at sea. The species’ preference for shallow waters (<50 m) makes it more vulnerable to small-scale inshore fisheries than to offshore trawling. For example, D. pastinaca made up more than 40% of the elasmobranch biomass captured in the trammel net fishery off the Balearic Islands (Morey et al. in review.). Small scale fisheries operating within this species’ shallow water range in the Mediterranean Sea and Atlantic make up an important component of the European fishing fleet (Stergiou et al. 2006). This species was not recorded in recent (1999-2000) experimental fishing trials with trammel nets conducted within several parts of this species’ known range in the Mediterranean and northeast Atlantic (Stergiou et al. 2006). There is a ban on trawling within 3 nm of the coast for EU countries, however there are some exceptions to this, and both legal and illegal trawling continues to occur in shallow waters in parts of the northern Mediterranean Sea.

Important grounds for reproduction (mating, parturition, nursery areas) seem to be associated with shallow sandy bottoms, which human disturbance (e.g. tourism activities on beaches) or fishing pressure (trammel and gillnets targeting cuttlefish, mullets, bass and flatfishes, and trawling) impact.

Citation

Serena, F., Mancusi, C., Morey, G. & Ellis, J.R. 2009. Dasyatis pastinacaThe IUCN Red List of Threatened Species 2009: e.T161453A5427586. https://dx.doi.org/10.2305/IUCN.UK.2009-2.RLTS.T161453A5427586.en. Downloaded on 09 February 2021.

Reproduction

Matrotrophic aplacental viviparity. 3-9 pups per litter.

Diet

Diet consists of benthic crustaceans, molluscs and small fishes.

Behavior

Spends much of the day resting on the substrate.

Reaction to divers

Shy but approachable with non-aggressive movements. Generally bolts if approached too closely.

Diving logistics

Tortonese’s stingrays are regularly encountered at numerous sites in the Mediterranean and Atlantic North Africa by Los Gigantes on Tenerife in the Canary Islands is the place to encounter this species close to Europe. Los Gigantes Dive Centre runs feeds twice weekly that attract up to six species of rays but this species is by far the most abundant.

Similar species

Common Stingray A very similar, sympatric ray that can be distinguished by it larger size, olive brown dorsal coloration, and less acutely pointed snout with a larger protruding tip.