Ray

Ray

  Ray, fish with cartilaginous skeleton, closely related to sharks and belonging to order Rajiformes, subclass Elasmobranchii. The order includes sawfishes, guitarfishes, sting rays, electric rays, mantas and skates. Rays occur widely in world oceans, with some also inhabiting tropical or subtropical estuaries. Skates of genus Raja are the most common batoid fishes in temperate and cool seas of higher latitudes. There are about 400 species of batoids, some 100 of which are skates of genus Raja. In Canada, there are 29 species of batoid fishes. Skates of genus Raja are the most common. Electric and sting rays also occur occasionally off both coasts.

Description
Rays are flattened dorsoventrally, the body appearing disclike. The pectoral fins are attached to the side of the head. The mouth, nostrils and 5 pairs of gill slits are located on the white lower surface. A pair of spiracles occurs on the upper surface behind the eyes. The skin may be smooth or variously covered with short spines. The tail is usually elongate and whiplike. Species vary greatly in size, from a disc width of about 30 cm in small forms up to 6 m and 1300 kg for the mantas. Rays swim by an undulating motion of the pectoral fins or by a winglike flapping of the whole fin. Most rays feed primarily on bottom organisms, which they crush with their specialized grinding teeth.

Reproduction
Skates are oviparous, depositing each large egg in a horny capsule, but most other rays bear living young.

Significance of Fishery
Rays are of little commercial importance. Skates are processed and marketed for food in Europe but in Canada they are a by-catch used mainly for fish meal and only occasionally eaten.