horse mackerel

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun Any of various edible carangid fishes of the genus Trachurus, especially T. trachurus of eastern Atlantic waters.
• noun Any of several tunas or related fishes.

from The Century Dictionary.

• noun One of several fishes more or less nearly related to the mackerel.
• noun In Sydney, Australia, Auxis ramsayi, of the family Scombridæ; in New Zealand, Trachurus trachurus, which is the same fish as the horse-mackerel of England.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun A large fish; variously the Australian bonito (Sarda australis), the pilot fish (Naucrates ductor), or the jack mackerel (genus Trachurus).

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun a California food fish
• noun largest tuna; to 1500 pounds; of mostly temperate seas: feed in polar regions but breed in tropics
• noun large elongated compressed food fish of the Atlantic waters of Europe