Skates and rays are flattened fishes related to sharks, with more than 100 species belonging to one family, the Rajidae, and the names are more or less interchangeable. The origional name 'skate' dates from the 12th century and referred to one species Raia batis, usually spoken of as the common skate. One of the largest is the big skate of the American Pacific Raia binoculata which grows to 8 ft.
Skates and rays are found in most temperature and tropical waters except for much of the South Pacific and an area off the northeast coast of America. They live mainly in shallow waters, sometimes down to 600 ft but the deep skate, Raia abyssicola, off the Pacific coast of North America, lives down to 7200 ft.

Although the skate is mainly a bottom living fish, it can swim well by means of undulations of its large pectoral fins. MMmmmmm, fish.