Cod is the common name for the genus Gadus of demersal fishes, belonging to the family Gadidae. Cod is also used as part of the common name for a number of other fish species, and some species suggested to belong to genus Gadus are not called cod (the Alaska pollock).
The two most common species of cod are the Atlantic cod (Gadus morhua), which lives in the colder waters and deeper sea regions throughout the North Atlantic, and the Pacific cod (Gadus macrocephalus), found in both eastern and western regions of the northern Pacific. Gadus morhua was named by Linnaeus in 1758. (However, G. morhua callarias, a low-salinity, nonmigratory race restricted to parts of the Baltic, was originally described as Gadus callarias by Linnaeus.)
Cod is popular as a food with a mild flavour and a dense, flaky, white flesh. Cod livers are processed to make cod liver oil, an important source of vitamin A, vitamin D, vitamin E, and omega-3 fatty acids (EPA and DHA). Young Atlantic cod or haddock prepared in strips for cooking is called scrod. In the United Kingdom, Atlantic cod is one of the most common ingredients in fish and chips, along with haddock and plaice.
At various times in the past, taxonomists included many species in the genus Gadus. Most of these are now either classified in other genera, or have been recognized as simply forms of one of three species. All these species have a number of common names, most of them ending with the word “cod”, whereas other species, as closely related, have other common names (such as pollock and haddock). However, many other, unrelated species also have common names ending with cod. The usage often changes with different localities and at different times.
Some fish commonly known as cod are unrelated to Gadus. Part of this name confusion is market-driven. Severely shrunken Atlantic cod stocks have led to the marketing of cod replacements using culinary names of the form “x cod”, according to culinary rather than phyletic similarity. The common names for the following species have become well established; note that all inhabit the Southern Hemisphere.
Fish of the order Perciformes that are commonly called “cod” include:
*Blue cod Parapercis colias
*Eastern freshwater cod Maccullochella ikei
*Mary River cod Maccullochella peelii mariensis
*Murray cod Maccullochella peelii peelii
*Potato cod Epinephelus tukula
*Sleepy cod Oxyeleotris lineolatus
*Trout cod Maccullochella macquariensis
*The cod icefish family, Nototheniidae, including:
#Antarctic cod Dissostichus mawsoni
#Black cod Notothenia microlepidota
#Maori cod Paranotothenia magellanica
#Rock cod, reef cod, and coral cod
Almost all coral cod, reef cod or rock cod are also in order Perciformes. Most are better known as groupers, and belong to the family Serranidae. Others belong to the Nototheniidiae. Two exceptions are the Australasian red rock cod, which belongs to a different order (see below), and the fish known simply as the rock cod and as soft cod in New Zealand, Lotella rhacina, which as noted above actually is related to the true cod (it is a morid cod).
From the order Scorpaeniformes:
*Ling cod Ophiodon elongatus
*Red rock cod Scorpaena papillosa
*Rock cod Sebastes
The tadpole cod family, Ranicipitidae, and the Eucla cod family, Euclichthyidae, were formerly classified in the order Ophidiiformes, but are now grouped with the Gadiformes.
Marketed as cod:
Some fish that do not have “cod” in their names are sometimes sold as cod. Haddock and whiting belong to the same family, the Gadidae, as cod.
Cods of the genus Gadus have three rounded dorsal and two anal fins. The pelvic fins are small, with the first ray extended, and are set under the gill cover (i.e. the throat region), in front of the pectoral fins. The upper jaw extends over the lower jaw, which has a well-developed chin barbel. The eyes are medium-sized, approximately the same as the length of the chin barbel. Cod have a distinct white lateral line running from the gill slit above the pectoral fin, to the base of the caudal or tail fin. The back tends to be a greenish to sandy brown, and shows extensive mottling, especially towards the lighter sides and white belly. Dark brown colouration of the back and sides is not uncommon, especially for individuals that have resided in rocky inshore regions.
The Atlantic cod can change colour at certain water depths. It has two distinct colour phases: gray-green and reddish brown. Its average weight is 5–12 kilograms (11–26 lb), but specimens weighing up to 100 kilograms (220 lb) have been recorded. Pacific cod are smaller than Atlantic cod and are darker in colour.
Atlantic cod (Gadus morhua) live in the colder waters and deeper sea regions throughout the North Atlantic. Pacific cod (Gadus macrocephalus) is found in both eastern and western regions of the Pacific.
Atlantic cod divide into several stocks, including the Arcto-Norwegian, North Sea, Faroe, Iceland, East Greenland, West Greenland, Newfoundland, and Labrador stocks. There seems to be little interchange between the stocks, although migrations to their individual breeding grounds may involve distances of 200 miles (320 km) or more.
Atlantic cod occupy varied habitat, favouring rough ground, especially inshore, and are demersal in depths between 20 and 200 feet (6.1 and 61.0 m), 80 metres (260 ft) on average, although not uncommonly to depths of 600 metres (2,000 ft). Off the Norwegian and New England coasts and on the Grand Banks of Newfoundland, cod congregate at certain seasons in water of 30–70 metres (98–230 ft) depth. Cod are gregarious and form schools, although shoaling tends to be a feature of the spawning season.
Spawning of northeastern Atlantic cod occurs between January and April (March and April are the peak months), at a depth of 200 metres (660 ft) in specific spawning grounds at water temperatures between 4 and 6 °C (39 and 43 °F). Around the UK, the major spawning grounds are in the middle to southern North Sea, the start of the Bristol Channel (north of Newquay), the Irish Channel (both east and west of the Isle of Man), around Stornoway, and east of Helmsdale.
Prespawning courtship involves fin displays and male grunting, which leads to pairing. The male inverts himself beneath the female, and the pair swim in circles while spawning. The eggs are planktonic and hatch between eight and 23 days, with larva reaching 4 millimetres (0.16 in) in length. This planktonic phase lasts some ten weeks, enabling the young cod to increase its body weight by 40-fold, and growing to about 2 centimetres (0.79 in). The young cod then move to the seabed and change their diet to small benthic crustaceans, such as isopods and small crabs. They increase in size to 8 centimetres (3.1 in) in the first six months, 14–18 centimetres (5.5–7.1 in) by the end of their first year, and to 25–35 centimetres (9.8–13.8 in) by the end of the second. Growth tends to be less at higher latitudes. Cod reach maturity at about 50 centimetres (20 in) at about 3 to 4 years of age.
Cod is popular as a food with a mild flavor and a dense, flaky white flesh. Cod livers are processed to make cod liver oil, an important source of vitamin A, vitamin D, vitamin E and omega-3 fatty acids (EPA and DHA).
Young Atlantic cod or haddock prepared in strips for cooking is called scrod. In the United Kingdom, Atlantic cod is one of the most common ingredients in fish and chips, along with haddock and plaice. Cod’s soft liver can be tinned (canned) and eaten. Cod is mainly consumed in Portugal, Spain, Italy and Brazil.
Health Benefits Of Eating Cod Fish:
*The most known health benefit of cod is that it is an excellent source of protein, while being low on calories at the same time. It also contains a variety of other essential nutrients.
*Studies have proved cod to be very useful for people suffering from atherosclerosis and diabetic heart disease. People, who eat cod fish regularly, are at a much lower risk of suffering from heart diseases and heart attack. More specifically, cod fosters cardiovascular health, as the omega-3 fatty acids contained in it are a good source of blood thinning.
*Cod is also a rich source of Vitamin B12 and B6. Both the vitamins are beneficial in keeping the homocysteine levels low in the body. Homocysteine is a molecule which is capable of damaging the walls of blood vessels in the body. High levels of homocysteine increases the risk of heart attacks and strokes.
*Cod is known to bring down the cholesterol levels, because it contains Niacin, which is another B vitamin. This vitamin plays a significant role in controlling the cholesterol levels in the body.
*The risk of arrhythmia and/or sudden death is significantly reduced by consuming the Omega 3 fatty acids, EPA and DHA, both of which are present in cod liver oil.
*Studies have also put forward strong claims to establish that the omega 3 fatty acids present in cod can effectively treat depression. Continued consumption of cod liver oil can greatly help in mood swings associated with bipolar disorder. Sufferers of bipolar disorder, who struggle to control their moods, are suggested to consume cod liver oil.
*A regular dose of cod liver oil helps fight rickets in children, which is a bone softening condition. It also prevents ear infections in children. It has been witnessed that babies of mothers who regularly consume cod liver oil are less prone to type-1 diabetes.
*Omega 3 fatty acids contained in cod can interfere with the ability of blood to clot, which increases the risk of hemorrhagic strokes.
*While cod makes for a low cal food, cod liver oil is high on calories and therefore, its consumption needs to be moderate and well regulated. Large amount of cod consumption can prove dangerous for other reasons as well. As it is very rich in many vitamins, over-consumption can be risky.
Some Cooking Tips:
*Cod is best cooked in moist heat, because of its lean meat. The ways to cook cod may include boiling, frying, baking, sauté and steaming.
*Cod fish can be made very succulent by poaching or steaming it. Slow cooking works best on cod to heighten its delicious flavor.
*Cod also cooks early due to its lean meat.
Disclaimer : The information presented herein is intended for educational purposes only. Individual results may vary, and before using any supplement, it is always advisable to consult with your own health care provider.