An icon of the North Atlantic, cod has been fished for more than 500 years, ever since the discovery of the New World. The fish lives in colder waters on both sides of the Atlantic and has been a traditional staple for Europeans and North Americans.
The colour of cod varies depending on its habitat, ranging from reddish brown to pay grey-green. It can be identified by a small barbell that extends from the chin of the fish to its whiskers. It has three dorsal fins, an almost square, broom-shaped tail and a disproportionately large heard on a streamlined body that allows it to swim at moderate speeds. On average, code weigh 11 to 26 pounds (5 to 12 kg). It has large, tender flakes that make for an incredibly juicy, delicious fish – perhaps the reason it has long been one of the most famous fish species.
Atlantic Cod, which can live as long as 25 years, usually reproduce for the first time at around five or six years old. The number of eggs produced in a given year, however, increases with both the size and the age of females. A one-metre female may lay about three million eggs, for example, while a 1.3-metre female may produce up to nine million eggs in one spawning season. Spawning, which usually happens in the coldest months between January and April, takes place at depths of one to 110 metres. While the females are releasing the eggs, the males swim around competing to fertilize them. Larvae measuring 5mm (0.2 inches) then hatch anywhere between 10 and 40 days after spawning, depending upon the water temperature. Larvae remain free-floating for around 10 weeks, enabling the young Cod to increase their body weight 40-fold. The young cod then move to the seabed and increase in size to 14-18cm (5.5-7.1 in) by the end of their first year. The mortality rate is, however, tremendous. Of the several million eggs each female spawns, only about one egg of each million succeeds in completing the cycle to become a mature cod.
Fish harvesters use bottom longlines to catch Atlantic Cod. Baited hooks are attached to lines that are anchored to the ocean floor.
Bottom Longline with Hooks
This fishery uses a bottom longline that is baited with hooks and anchored to the ocean floor. A longline can be from 1 to 3 miles (1.6 to 5 km) long and have up to 2,000 hooks.
This fishery uses a large cone-shaped net that is dragged along the seafloor to catch fish. As the net is towed at low speed, hydrodynamic forces push two "otter boards" outwards opening the mouth of the net and capturing fish in its path.