Mackerel is a handsome but underrated fish, probably because it doesn’t have the mild-whitefish profile American consumers are most comfortable with. The mackerel looks a lot like its cousin, the tuna, but smaller — usually 1 1/2 to 2 1/2 pounds. Shaped for swift swimming, the Atlantic mackerel moves quickly when danger threatens — up to 70 mph. Mackerel travel in large schools on both sides of the Atlantic Ocean. In the Northwest Atlantic, mackerel range from northern Carolina to southern Labrador. In the eastern Atlantic, they are found off Iceland and northern Norway. Europeans harvest them by freezer trawlers. The purse seine is the harvest method of choice for North American fishermen. Immature mackerel, called tinkers, are available in spring and weigh less than a pound. They are a traditional seasonal treat in New England and sell for a considerably lower price than mature fish, which reach their prime in the summer months.