Brown Stingray: Bathytoshia lata

Family: Dasyatidae
Common name(s)

Brown Stingray, Black Stingray.

Identification

A very large, thick bodied stingray with a kite-shaped disc that is slightly wider than long; disc width approximately 1.2-1.3 x length. Snout short and obtuse with a small, triangular, protruding tip. Anterior margins of disc mildly undulate. Pectoral fin apexes narrowly rounded or angular. Pelvic fins relatively small with narrowly rounded or angular apexes.
Eyes relatively small. Snout length 2.1-2.5 x combined eye and spiracle length.
Mouth contains 3-5 oral papillae. Weak labial furrows around mouth. Lower jaw weakly convex. Extremely broad, skirt shaped nasal curtain with a fringed margin. Nostrils oval shaped. Dorsal surface of juveniles lacks dermal denticles except for a row of stellate thorns and tubercles on midline. Adults have more pronounced thorns on midline, and generally more granulate skin including small thorns on snout, . Sharp thornlets cover tail beyond caudal spine. Tail wide and depressed at base; tapering gently to tail spine. Tail beyond spines thin and covered in small thorns. Tail length (when intact) 2x disc width. Dorsal finfold indistinct. Ventral finfold long and low; basal length equal to distance between snout and cloaca.

Colour

Dorsum uniformly grey-brown or almost black. No visible rows of white pores pectoral fins. Ventrum white; usually with a dusky disc margin. Tail fades to black beyond tail spine.

Size

Maximum disc width possibly 260cm. Disc width at birth approximately 35cm.

Habitat

Temperate and tropical seas. On soft substrates, sometimes adjacent to reefs. From shallow bays to 800m on the continental slope.

Distribution

Wide ranging but absent from the Americas. The brown stingray is found throughout the Mediterranean southward to southwest Africa. It has a patchy distribution in the Indian Ocean and southeast Asia, but is quite common in southern Australia. Also in the west and central Pacific to Hawaii.

Conservation Status

LEAST CONCERN (AWAITING REVIEW)

In the Mediterranean the brown stingray is taken as bycatch of the artisanal fisheries, bottom set longline, gillnet and handline (Fischer et al. 1987). Benthic trawl effort has increased both effort and efficiency in the shelf and slope areas of the Mediterranean Sea over the last 50 years. The continental shelf and upper slope of the Mediterranean Sea are highly exploited, with intensive commercial trawling occurring at depths ranging from 50 to 700-800 m (Colloca et al. 2003, Massuti and Moranta 2003). As a result there has been increasing concern about changes in the abundance and diversity of elasmobranchs in this region, and decreases in the abundance and biomass of some species throughout the last decade have been reported in highly exploited areas such as the Gulf of Lions (Aldebert 1997, Massuti and Moranta 2003). Although no species specific data are available, the very large size of D. centroura makes it intrinsically vulnerable to population depletion. Given that this species is rarely captured in the Mediterranean, high exploitation of the continental shelf, its intrinsic vulnerability and evidence for declines where data are available in other elasmobranch species within this region, it is suspected to have declined.

Citation

Ebert, D.A., Vidthayanon, D.A. & Samiengo, B. 2016. Bathytoshia lata. The IUCN Red List of Threatened Species 2016: e.T161386A104066775. http://dx.doi.org/10.2305/IUCN.UK.2016-3.RLTS.T161386A104066775.en. Downloaded on 23 October 2017.

Reproduction

Matrotrophic aplacental viviparity. Litter size unknown.

Diet

Diet consists of crabs, prawns, 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 closely.

Diving logistics

Brown stingrays are regularly encountered at numerous sites in the Mediterranean and around southern Australia. In Australia, they are often referred to as black stingrays or sometimes bull rays.

CANARY ISLANDS
Los Gigantes on Tenerife 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 usually including this one.

AUSTRALIA & NEW ZEALAND
Sightings in Australia and NZ occur mostly during November and February. This species appears to be more migratory than the sympatric short-tail stingray.
Good spots appear to along the coast of New South Wales, and at dive sights in the far north of New Zealand. However, this could be simply because these areas are well populated and dived more regularly.

Similar species

Short-tail Stingray Distinguished by white spots on pectoral fins and shorter tail.