Common name: Cod
Latin name: Gadus morhua
Record weight: As a result of over-fishing the boat caught cod record is likely to remain safe for many years to come. Although some good fish are still taken every year, a fish to equal the 58lb 6oz record is extremely unlikely. The shore record of 44lb 8oz is also relatively safe, although in the past, before fishing pressure removed the largest fish, cod could approach almost 200lb in weight!
Distribution: Cod are found throughout the Northern Hemisphere from the North Sea to the Arctic Ocean. Cod can be found in water down to 600m, although in the Spring they move into shallower water of less than 100m deep to spawn.
Features: Like other members of it's family, the cod has a large single barbule extending from the centre of the lower jaw. Cod have three dorsal fins and two ventral fins for increased manoeuvrability. The dark mottled brown back, fading to a cream underbelly is also very conspicuous on cod of all sizes and sets them apart from the mainly battleship grey pelagic fish. Occasionally a pink form is also found which has a striking red-gold colouration.
Diet: Cod have a large mouth sporting a ring of fine teeth around the lips. This, coupled with their large eye, suggests that cod are active predators. In fact their diet consists of large quantities of small fish, particularly juvenile herring and sprat. Sandeel and crustaceans can also be important food resources, particularly for the younger cod that are found in shallower water.
Spawning: Cod move into water of less than a 100m deep between February and April to spawn depending upon the latitude. The cod form large shoals close to the sea bed where the eggs and milt are released. The fertilised eggs are slightly buoyant and rise towards the surface where they drift for around 12 days before hatching. The young cod are only 4mm in length, but begin to feed upon microscopic plankton immediately and reach a length of around 50mm after three months.
Growth: Cod are a relatively fast growing species reaching a weight of several pounds in their first few years. Unfortunately, as a result of severe over-fishing we do not see the huge fish of two centuries ago. Fishing acts as an evolutionary pressure upon the fish, as those which mature at a smaller size and spawn whilst young have a better chance of passing their genes on to the next generation. Any fish that puts its energy into growth rather than producing eggs will find that it is caught before it has the chance to spawn. For this reason there has been a distinct shift in the population dynamics of the cod and even if fishing were to stop completely the fortunes of the cod are far from certain.