Mackerel are members of the Scombridae family, which includes tuna (see) and numbers some 50 species in 15 genera.
Mackerel and tuna are both mainly schooling fish of the open sea. They provide sport virtually wherever they are found, and they contribute significantly to commercial fisheries, because they are good to eat. And all are good fighters as well; larger mackerel can rip line from a reel with tremendous speed, and some even take to the air on occasion.
Like tuna, mackerel are especially streamlined. The body is literally a spindle, with a pointed head and a much-tapered tail. The large caudal fin is lunate (crescent-shaped). Mackerel are much smaller than tuna overall, but they are just as speedy, displaying swift attacking speeds. Some of these fish have slots into which their spinous dorsal fins fit; this adaptation further reduces friction and enhances their speed. The spiny and soft-rayed dorsal fins are separate, and the soft-rayed dorsal fin is matched in size and shape by the **** fin directly beneath it. Following each fin is a series of finlets, the number varying with the species. In all species, the scales are extremely small or lacking. Most tuna and mackerel are ocean blue or greenish on the back, grading to a silvery shade on the sides and the belly. Some notable exceptions do occur, however.
Angling techniques for mackerel vary to some extent with locations and species. Trolling rigged baits and lures, and fishing baits from a drifting or anchored boat, are predominant methods. Casting plays a minor role, and then typically when chumming attracts the fish close to a boat. Surf and shore fishing are seldom productive, except for a few smaller coastal species.