Phylum: Chordata - Class: Elasmobranchii - Order: Rajiformes - Family: Rajidae
This is the commonest of the rays found around the coast of Britain, and much of the so-called 'skate' sold in fish shops is in fact thornback. In 1981 a 31lb 7oz (nearly 15kg) Thornback Ray was caught by Mr J Wright fishing from a boat off the North Wales coast, and this specimen holds the British rod-caught record.
The upper body is covered in prickles and, once the fish is mature, a number of large spines - hence its common name.
Found usually over sand and mud in water of 10 to 60m depth, Thornback Rays will move into the shallows in spring when they are ready to spawn. They lay their eggs between March and August, and it takes about five months for the eggs to hatch.
Young Thornback Rays feed on crustaceans and other bottom-dwelling creatures, switching more to eating crabs and small fishes as they develop. They reach maturity in about eight years.
To avoid taking in silt when resting on the bottom, Thornbacks draw water into their gill chamber through a hole just behind the eye - this aperture is called a spiracle.