Cod is a type of ocean dwelling fish that prefers cold, deep waters such as those found in the Arctic. It has formed a staple part of the European diet for centuries, and is still popular in England and Portugal in fresh and salted forms, respectively. Like many other fish, its survival is uncertain due to overfishing, threats to the environment, and high levels of mercury bioaccumulation.
Many cod have barbels or whiskers on their faces which resemble large drooping mustaches. They also have a thrusting jaw and blunt head which cause them to look somewhat like a bulldog. Many species are bottom dwelling, and eat small crustaceans and other fish. They can live to be 15 years old and can weigh up to 66 pounds (30 kilograms) in extreme cases. Most reach maturity and begin to breed at about six years old, putting out large clouds of eggs.
This fish was considered a major food source for centuries, and was the building block of several nations including the United States, which turned a very large profit on preserved cod when it was a British colony. It has dense white flesh with minimal oil, which makes it ideal for preservation in salt, because it can be split, salted, and dried without the risk of going rancid or rotting. Salted cod, sometimes also known as clipfish, is extremely hard, and could be stacked into wagons for shipping all over Europe.
Clipfish is still popular in Portugal, where it is called bacalhau and used in many traditional dishes. It's typically soaked before use to soften it and remove some of the salt. This food is also common in the Caribbean, where it was introduced as a primary source of protein for slave populations. Many cultures built an economy off of it, notably the Basque people, who traded cod for more salt with which to salt the next catch. It was also popular in Scandinavian cuisines.
In modern times, this fish is commonly used for the English dish of fish and chips, though this is becoming increasingly rare due to its conservation status. Atlantic cod is considered to be a threatened species by marine biologists, who encourage careful stewarding fisheries and a severe reduction on commercial fishing. This has generally affected smaller fishing communities more than large corporations.
In the northern Pacific, ling cod is still commonly commercially fished, and is famous for growing very large. Like Atlantic cod, the once plentiful species is at risk due to overfishing, with stocks growing small every year. More careful stewardship of fisheries in the Pacific has been recommended by marine conservation organizations to prevent the disappearance of this fish.