Sepia Stingray: Urolophus aurantiacus

Family: Urolophidae
Common name(s)

Sepia Stingray, Oriental Stingaree.

Identification

A small stingaree with a sub-circular or rounded kite-shaped disc that is slightly wider than long. Snout obtusely angular, sometimes with a small acutely pointed tip. Anterior margins of disc mildly convex, apices broadly rounded. Disc completely smooth.
Eyes large; orbit length 0.28-0.36 x snout length. Spiracle origin below mid-eye. Mouth small. 7 oral papillae on mouth floor; 5 centrally and 2 laterally. Nasal curtain skirt shaped, extended posteriorly into a distinct lobe, posterior margin weakly fringed. No fleshy lobe on each nostril.
Tail long and relatively broad-based, length 0.72-0.84 x disc length. Dorsal fin absent. Caudal fin relatively short and deep.

Colour

Dorsum light to dark greyish brown with no distinct markings except for a dark stripe along midline and tail. Area around eyes and dorsal disc margin sometimes dusky. Ventrum white with a broad, dark margin.

Size

Total length at least 40cm. Length at birth approximately 8cm.

Habitat

Tropical to temperate seas. Found on sandy and muddy substrates at deeper depth, and rockier substrates or sandy areas adjacent to rocky reefs at shallower depths. The sepia stingray was previously considered to be a deepwater species occurring at 155-205m but there are numerous reports of sightings in 10-30m by divers in Japan.

Distribution

Northwestern Pacific. Taiwan, mainland China, South Korea, and southern Japan where it is quite common.

Conservation Status

VULNERABLE

The oriental stingaree is a bycatch of trawl and gillnet fisheries and is retained for fish meal. Landings data of all skates combined from the Taiwan Exclusive Economic Zone (EEZ) and reconstructed catches of all sharks, skates, and rays from the Japan, China, and South Korea EEZs indicate declines of 48–95% over the past three generation lengths (38 years). Historic and current fishing pressure is high across the species’ range. It may have some refuge from fishing pressure in inshore rocky habitats, and in parts of southern Japan where trawl pressure is decreasing. Inshore and seasonal trawl bans in China and Taiwan may also afford the species some refuge. It is inferred that the Oriental Stingaree has undergone a population reduction of 30–49% over the past three generation lengths (38 years) due to levels of exploitation, and it is assessed as Vulnerable A2d.

Citation

Rigby, C.L., Chen, X., Ebert, D.A., Herman, K., Ho, H., Hsu, H. & Zhang, J. 2020. Urolophus aurantiacusThe IUCN Red List of Threatened Species 2020: e.T60087A124438082. https://dx.doi.org/10.2305/IUCN.UK.2020-3.RLTS.T60087A124438082.en. Downloaded on 23 March 2021.

Reproduction

Viviparous, probably with trophodermic nutrition. 1-2 pups per litter. Gestation approximately 12 months.

Diet

Diet unrecorded.

Behavior

Poorly known.

Reaction to divers

Skittish but approachable with non-threatening movements. Will bolt if approached too closely but does not travel far before resettling.

Diving logistics

The sepia stingaree is relatively common on shallow reefs in southern Honshu, Japan. We (big Fish Expeditions) regularly see this species during our Japan Shark Safaris at dive sites in Chiba. It is probably quite common along the entire south coast of Honshu.

Similar species

The sepia stingray is the only stingaree that occurs in the northern hemisphere.