The scales are small and smooth. The mouth is large with a projecting upper jaw and the gill openings are wide. The lateral line of the cod is pale, and the tail is slightly concave, almost square. G enerally cod average 2 to 3 kg in weight and about 60 to 70 cm in length. They usually do not exceed 30 kg, but there is one record of a cod that weighed about 96 kg and was more than 180 cm long.
Atlantic cod grow at different rates in different areas.
There are annual differences in growth rate in the same area depending upon population sizes, temperature, and food. Generally, growth is slower off Labrador and eastern Newfoundland than on the southern Grand Banks and is slower in the Gulf of St. Lawrence than on the Scotian Banks and Georges Bank. Most of the cod caught by fishermen in Atlantic Canada are from four to eight years old. Juveniles feed mainly on shrimp, amphipods, euphausiids, and fish and shellfish larvae. Adult cod feed mainly on capelin, herring, sand launce, flounders, young Greenland turbot, crabs, shrimp, brittle stars, combjellies, and a host of other species of fish and shellfish.