The
thornback ray (Raja clavata) or thornback skate is a species of fish in the
Rajidae family. It is found in coastal waters of Europe and the Atlantic coast
of Africa, possibly as far south as Namibia
and even South Africa .
Its natural habitats are open seas and shallow seas. It is sometimes seen
trapped in large estuarine pools at low tide.
The
thornback ray is probably one of the most common rays encountered by divers.
Like all rays, it has a flattened body with broad, wing-like pectoral fins. The
body is kite-shaped with a long, thorny tail. The back is covered in numerous
thorny spines, as is the underside in older females. Adult fish can grow to 1 m
(3.3 ft) in length, although most are less than 85 cm (33.67 in). This ray can
weigh from 4.5 to 8.75 lb (2 to 4 kg).
In
sexually mature fish, some of the spines are thickened with button-like bases
(known as bucklers). These are particularly well developed on the tails and
backs of sexually mature females. Their colours vary from light brown to grey
with darker blotches and numerous small darker spots and yellow patches.
Sometimes the yellow patches are surrounded by small dark spots. The underside
is creamy-white with a greyish margin.When threatened they can appear black.
The
thornback ray is usually found on sedimentary seabeds such as mud, sand or
gravel at depths between 10 and 60 m. Juvenile fish feed on small crustaceans,
particularly amphipods and bottom-living shrimps; adults feed on crabs, shrimps
and small fish.
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