[Thornback ray articles]
Common name: Thornback ray
Latin name: Raja clavata
Record weight: One of the commoner ray species in many parts of the country, small thornbacks up to around ten pounds are very common. The current boat record stands at 31lb 7oz, whilst the shore best is 21lb 12oz.
Distribution: The thornback is generally very common around the British Isles, although it is often known by other names. Most of the skate sold in fish shops is in fact thornback ray, and in the Southeast the fish has the local name roker. Thornbacks are found in relatively shallow water close to the shore, preferring water of between 10m to 60m deep. Look for the best thornback sport in clean sandy water where the current is not pulling too strong.
Features: The thornback ray shares the typical shape of other members of its family, a design perfected for living on the sea bed. The upper body is covered with sharp spikes along the spine and fanning out along the wings. The males have four rows of spines, whilst the females have even more spines, even on the underside of the body. The upper surface is a mottled brown appearance with grey patches. The lower surface is unpigmented.
Diet: Small thornbacks feed primarily on crustaceans, such as brown shrimps and small crabs. As the fish grow they become more piscivorous, switching to a diet dominated by sand-eels and sprats. Thornback can be caught on a whole range of baits, with squid, mackerel and worm all taking good fish.
Spawning: Although they do not undergo a distinct migration, thornbacks appear to move inshore slightly to spawn. Females mature at about nine years of age, whilst males mature a little sooner at about seven years of age. Thornbacks have internal fertilisation, with the male passing a packet of sperm to the females using the pair of pelvic claspers laying either side of the tail. The female holds the developing egg capsules for several weeks before the mermaids purses are released. The purses of the thornback ray are around 60mm long with pointed corners, rather than the sticky threads found in dogfish. The eggs take about 20 weeks to hatch and the now free-swimming ray is still reliant upon its yolk sac for a few more weeks before it begins to feed upon shrimps.