Patrice Murphy, age 11, of St. Augustine, Fla., for her question:

HOW LARGE WILL A MACKEREL BECOME?

Mackerel is the common name for a marine spiny finned food fish that is found on both sides of the Atlantic Ocean and also in the Mediterranean Sea. The fish, which is blue on the top and silver below, grows to about 20 inches and weighs about three pounds.

The mackerel has a pointed head, with a large mouth, and a thick, narrow body that tapers just before the bilobed tail. It has small finlets behind the dorsal and anal fins.

The mackerel's head is scaleless but the body is covered with many small scales.

Mackerels swim in large schools near the surface of the water, feeding on small fish and crustaceans. They remain at sea during late spring and early summer to spawn. The eggs are laid primarily at night and float on the surface.

Mackerel fishing is a major industry in the United States, southeastern Canada, Ireland, Great Britain and Norway.