Seafood - AbsoluteAstronomy.com

See also: Fish as food. For the UK band, see Seafood (band)
Seafood (band)
Seafood were a UK band formed in London around 1996.The line-up included chief songwriter David Line , Caroline Banks and Kevin Penney who joined the band following the departure of founder-member Charles MacLeod...

.

Seafood is any form of marine life regarded as food

Food

Food is any substance consumed to provide nutritional support for the body. It is usually of plant or animal origin, and contains essential nutrients, such as carbohydrates, fats, proteins, vitamins, or minerals...

by humans. Seafoods include fish

Fish

Fish are a paraphyletic group of organisms that consist of all gill-bearing aquatic vertebrate animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish, as well as various extinct related groups...

, molluscs (octopus

Octopus

The octopus is a cephalopod mollusc of the order Octopoda. Octopuses have two eyes and four pairs of arms, and like other cephalopods they are bilaterally symmetric. An octopus has a hard beak, with its mouth at the center point of the arms...

and shellfish

Shellfish

Shellfish is a culinary and fisheries term for exoskeleton-bearing aquatic invertebrates used as food, including various species of molluscs, crustaceans, and echinoderms. Although most kinds of shellfish are harvested from saltwater environments, some kinds are found only in freshwater...

), crustacean

Crustacean

Crustaceans form a very large group of arthropods, usually treated as a subphylum, which includes such familiar animals as crabs, lobsters, crayfish, shrimp, krill and barnacles. The 50,000 described species range in size from Stygotantulus stocki at , to the Japanese spider crab with a leg span...

s (shrimp

Shrimp

Shrimp are swimming, decapod crustaceans classified in the infraorder Caridea, found widely around the world in both fresh and salt water. Adult shrimp are filter feeding benthic animals living close to the bottom. They can live in schools and can swim rapidly backwards. Shrimp are an important...

and lobster

Lobster

Clawed lobsters comprise a family of large marine crustaceans. Highly prized as seafood, lobsters are economically important, and are often one of the most profitable commodities in coastal areas they populate.Though several groups of crustaceans are known as lobsters, the clawed lobsters are most...

), echinoderm

Echinoderm

Echinoderms are a phylum of marine animals. Echinoderms are found at every ocean depth, from the intertidal zone to the abyssal zone....

s (sea cucumber

Sea cucumber

Sea cucumbers are echinoderms from the class Holothuroidea.They are marine animals with a leathery skin and an elongated body containing a single, branched gonad. Sea cucumbers are found on the sea floor worldwide. There are a number of holothurian species and genera, many of which are targeted...

and sea urchin

Sea urchin

Sea urchins or urchins are small, spiny, globular animals which, with their close kin, such as sand dollars, constitute the class Echinoidea of the echinoderm phylum. They inhabit all oceans. Their shell, or "test", is round and spiny, typically from across. Common colors include black and dull...

s). Edible sea plants, such as some seaweed

Seaweed

Seaweed is a loose, colloquial term encompassing macroscopic, multicellular, benthic marine algae. The term includes some members of the red, brown and green algae...

s and microalgae, are also seafood, and are widely eaten around the world, especially in Asia (see the category of sea vegetables). In North America

North America

North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...

although not generally in the United Kingdom

United Kingdom

The United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages...

, the term seafood applies also to any fresh water

Fresh Water

Fresh Water is the debut album by Australian rock and blues singer Alison McCallum, released in 1972. Rare for an Australian artist at the time, it came in a gatefold sleeve...

life eaten by humans, so all edible aquatic life can be referred to as seafood.

The harvesting of wild seafood is known as fishing

Fishing

Fishing is the activity of trying to catch wild fish. Fish are normally caught in the wild. Techniques for catching fish include hand gathering, spearing, netting, angling and trapping....

and the cultivation and farming of seafood is known as aquaculture

Aquaculture

Aquaculture, also known as aquafarming, is the farming of aquatic organisms such as fish, crustaceans, molluscs and aquatic plants. Aquaculture involves cultivating freshwater and saltwater populations under controlled conditions, and can be contrasted with commercial fishing, which is the...

, mariculture

Mariculture

Mariculture is a specialized branch of aquaculture involving the cultivation of marine organisms for food and other products in the open ocean, an enclosed section of the ocean, or in tanks, ponds or raceways which are filled with seawater. An example of the latter is the farming of marine fish,...

, or in the case of fish, fish farming

Fish farming

Fish farming is the principal form of aquaculture, while other methods may fall under mariculture. Fish farming involves raising fish commercially in tanks or enclosures, usually for food. A facility that releases young fish into the wild for recreational fishing or to supplement a species'...

. Seafood is often distinguished from meat

Meat

Meat is animal flesh that is used as food. Most often, this means the skeletal muscle and associated fat and other tissues, but it may also describe other edible tissues such as organs and offal...

, although it is still animal and is excluded in a strict vegetarian diet. Seafood is an important source of protein

Protein

Proteins are biochemical compounds consisting of one or more polypeptides typically folded into a globular or fibrous form, facilitating a biological function. A polypeptide is a single linear polymer chain of amino acids bonded together by peptide bonds between the carboxyl and amino groups of...

in many diet

Diet (nutrition)

In nutrition, diet is the sum of food consumed by a person or other organism. Dietary habits are the habitual decisions an individual or culture makes when choosing what foods to eat. With the word diet, it is often implied the use of specific intake of nutrition for health or weight-management...

s around the world, especially in coastal areas.

Types of seafood

There are over 32,000 species

Species

In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...

of fish

Fish

, making them the most diverse group of vertebrates. However, only a small number of species are commonly eaten as food fish.

The principal food fish species groups are:

Anchovy
Anchovy
Anchovies are a family of small, common salt-water forage fish. There are 144 species in 17 genera, found in the Atlantic, Indian, and Pacific Oceans. Anchovies are usually classified as an oily fish.-Description:...
Carp
Carp
Carp are various species of oily freshwater fish of the family Cyprinidae, a very large group of fish native to Europe and Asia. The cypriniformes are traditionally grouped with the Characiformes, Siluriformes and Gymnotiformes to create the superorder Ostariophysi, since these groups have certain...
Catfish
Catfish
Catfishes are a diverse group of ray-finned fish. Named for their prominent barbels, which resemble a cat's whiskers, catfish range in size and behavior from the heaviest and longest, the Mekong giant catfish from Southeast Asia and the second longest, the wels catfish of Eurasia, to detritivores...
Cod
Cod
Cod is the common name for genus Gadus, belonging to the family Gadidae, and is also used in the common name for various other fishes. Cod is a popular food with a mild flavor, low fat content and a dense, flaky white flesh. Cod livers are processed to make cod liver oil, an important source of...
Eel
Eel
Eels are an order of fish, which consists of four suborders, 20 families, 111 genera and approximately 800 species. Most eels are predators...
Haddock
Haddock
The haddock , also known as the offshore hake, is a marine fish distributed on both sides of the North Atlantic. Haddock is a popular food fish and is widely fished commercially....
Halibut
Halibut
Halibut is a flatfish, genus Hippoglossus, from the family of the right-eye flounders . Other flatfish are also called halibut. The name is derived from haly and butt , for its popularity on Catholic holy days...
Herring
Herring
Herring is an oily fish of the genus Clupea, found in the shallow, temperate waters of the North Pacific and the North Atlantic oceans, including the Baltic Sea. Three species of Clupea are recognized. The main taxa, the Atlantic herring and the Pacific herring may each be divided into subspecies...
Mackerel
Mackerel
Mackerel is a common name applied to a number of different species of fish, mostly, but not exclusively, from the family Scombridae. They may be found in all tropical and temperate seas. Most live offshore in the oceanic environment but a few, like the Spanish mackerel , enter bays and can be...
Salmon
Salmon
Salmon is the common name for several species of fish in the family Salmonidae. Several other fish in the same family are called trout; the difference is often said to be that salmon migrate and trout are resident, but this distinction does not strictly hold true...
Sardine
Sardine
Sardines, or pilchards, are several types of small, oily fish related to herrings, family Clupeidae. Sardines are named after the Mediterranean island of Sardinia, around which they were once abundant....
Scad
Carangidae
Carangidae is a family of fish which includes the jacks, pompanos, jack mackerels, and scads.They are marine fish found in the Atlantic, Indian and Pacific Oceans...
Snapper
Lutjanidae
Snappers are a family of perciform fish, mainly marine but with some members inhabiting estuaries, feeding in freshwater. Some are important food fish. One of the best known is the red snapper....
Tilapia
Tilapia
Tilapia , is the common name for nearly a hundred species of cichlid fish from the tilapiine cichlid tribe. Tilapia inhabit a variety of fresh water habitats, including shallow streams, ponds, rivers and lakes. Historically, they have been of major importance in artisan fishing in Africa and the...
Trout
Trout
Trout is the name for a number of species of freshwater and saltwater fish belonging to the Salmoninae subfamily of the family Salmonidae. Salmon belong to the same family as trout. Most salmon species spend almost all their lives in salt water...
Tuna
Tuna
Tuna is a salt water fish from the family Scombridae, mostly in the genus Thunnus. Tuna are fast swimmers, and some species are capable of speeds of . Unlike most fish, which have white flesh, the muscle tissue of tuna ranges from pink to dark red. The red coloration derives from myoglobin, an...

Perishability

Fish is a highly perishable

Decomposition

Decomposition is the process by which organic material is broken down into simpler forms of matter. The process is essential for recycling the finite matter that occupies physical space in the biome. Bodies of living organisms begin to decompose shortly after death...

product. The fishy smell of dead fish is due to the breakdown of amino acids into biogenic amines

Polyamine

A polyamine is an organic compound having two or more primary amino groups .This class of compounds includes several synthetic substances that are important feedstocks for the chemical industry, such as ethylene diamine , 1,3-diaminopropane , and hexamethylenediamine...

and ammonia

Ammonia

Ammonia is a compound of nitrogen and hydrogen with the formula . It is a colourless gas with a characteristic pungent odour. Ammonia contributes significantly to the nutritional needs of terrestrial organisms by serving as a precursor to food and fertilizers. Ammonia, either directly or...

.

Live food fish are often transported in tanks at high expense for an international market

Live food fish trade

The live fish trade can refer to the live food fish trade or to the ornamental fish trade . The fish can come from many places, but most comes from Southeast Asia....

that prefers its seafood killed immediately before it is cooked. This process originally was started by Lindeye. Delivery of live fish without water is also being explored. While some seafood restaurant

Restaurant

A restaurant is an establishment which prepares and serves food and drink to customers in return for money. Meals are generally served and eaten on premises, but many restaurants also offer take-out and food delivery services...

s keep live fish in aquaria

Aquarium

An aquarium is a vivarium consisting of at least one transparent side in which water-dwelling plants or animals are kept. Fishkeepers use aquaria to keep fish, invertebrates, amphibians, marine mammals, turtles, and aquatic plants...

for display purposes or for cultural beliefs, the majority of live fish are kept for dining customers. The live food fish trade in Hong Kong

Hong Kong

Hong Kong is one of two Special Administrative Regions of the People's Republic of China , the other being Macau. A city-state situated on China's south coast and enclosed by the Pearl River Delta and South China Sea, it is renowned for its expansive skyline and deep natural harbour...

, for example, is estimated to have driven imports of live food fish to more than 15,000 tonne

Tonne

The tonne, known as the metric ton in the US , often put pleonastically as "metric tonne" to avoid confusion with ton, is a metric system unit of mass equal to 1000 kilograms. The tonne is not an International System of Units unit, but is accepted for use with the SI...

s in 2000. Worldwide sales that year were estimated at US$400 million, according to the World Resources Institute.

If the cool chain has not been adhered to correctly, food products generally decay and become harmful before the validity date

Shelf life

Shelf life is the length of time that food, drink, medicine, chemicals, and many other perishable items are given before they are considered unsuitable for sale, use, or consumption...

printed on the package. As the potential harm for a consumer when eating rotten fish is much larger than for example with dairy products, the U.S. Food and Drug Administration (FDA) has introduced regulation in the USA requiring the use of a time temperature indicator

Time temperature indicator

A time temperature indicator is a device or smart label that shows the accumulated time-temperature history of a product. Time temperature indicators are commonly used on food, pharmaceutical, and medical products to indicate exposure to excessive temperature .-Technology:There are a large number...

on certain fresh chilled seafood products.

Preservation

Fresh fish is a highly perishable food product, so it must be eaten promptly or discarded; it can be kept for only a short time. In many countries, fresh fish are filleted

Fillet (cut)

A fillet is a cut or slice of boneless meat or fish.- Meat :In the case of beef, in the USA, the term most often refers to beef tenderloin, especially filet mignon.- Chicken :...

and displayed for sale on a bed of crushed ice or refrigerated

Refrigeration

Refrigeration is a process in which work is done to move heat from one location to another. This work is traditionally done by mechanical work, but can also be done by magnetism, laser or other means...

. Fresh fish is most commonly found near bodies of water, but the advent of refrigerated train

Refrigerator car

A refrigerator car is a refrigerated boxcar , a piece of railroad rolling stock designed to carry perishable freight at specific temperatures. Refrigerator cars differ from simple insulated boxcars and ventilated boxcars , neither of which are fitted with cooling apparatus...

and truck

Refrigerator truck

A refrigerator truck is a van or truck designed to carry perishable freight at specific temperatures. Like refrigerator cars, refrigerated trucks differ from simple insulated and ventilated vans , neither of which are fitted with cooling apparatus...

transportation has made fresh fish more widely available inland.

Long term preservation

Food preservation

Food preservation is the process of treating and handling food to stop or slow down spoilage and thus allow for longer storage....

of fish is accomplished in a variety of ways. The oldest and still most widely used techniques are drying

Stockfish

Stockfish is unsalted fish, especially cod, dried by cold air and wind on wooden racks on the foreshore, called "hjell". The drying of food is the world's oldest known preservation method, and dried fish has a storage life of several years...

and salting

Salting (food)

Salting is the preservation of food with dry edible salt. It is related to pickling . It is one of the oldest methods of preserving food, and two historically significant salt-cured foods are dried and salted cod and salt-cured meat.Salting is used because most bacteria, fungi and other potentially...

. Desiccation

Desiccation

Desiccation is the state of extreme dryness, or the process of extreme drying. A desiccant is a hygroscopic substance that induces or sustains such a state in its local vicinity in a moderately sealed container.-Science:...

(complete drying) is commonly used to preserve fish such as cod

Cod

Cod is the common name for genus Gadus, belonging to the family Gadidae, and is also used in the common name for various other fishes. Cod is a popular food with a mild flavor, low fat content and a dense, flaky white flesh. Cod livers are processed to make cod liver oil, an important source of...

. Partial drying and salting is popular for the preservation of fish like herring

Herring

Herring is an oily fish of the genus Clupea, found in the shallow, temperate waters of the North Pacific and the North Atlantic oceans, including the Baltic Sea. Three species of Clupea are recognized. The main taxa, the Atlantic herring and the Pacific herring may each be divided into subspecies...

and mackerel

Mackerel

Mackerel is a common name applied to a number of different species of fish, mostly, but not exclusively, from the family Scombridae. They may be found in all tropical and temperate seas. Most live offshore in the oceanic environment but a few, like the Spanish mackerel , enter bays and can be...

. Fish such as salmon

Salmon

Salmon is the common name for several species of fish in the family Salmonidae. Several other fish in the same family are called trout; the difference is often said to be that salmon migrate and trout are resident, but this distinction does not strictly hold true...

, tuna

Tuna

Tuna is a salt water fish from the family Scombridae, mostly in the genus Thunnus. Tuna are fast swimmers, and some species are capable of speeds of . Unlike most fish, which have white flesh, the muscle tissue of tuna ranges from pink to dark red. The red coloration derives from myoglobin, an...

, and herring

Herring

are cooked and canned

Canning

Canning is a method of preserving food in which the food contents are processed and sealed in an airtight container. Canning provides a typical shelf life ranging from one to five years, although under specific circumstances a freeze-dried canned product, such as canned, dried lentils, can last as...

. Most fish are filleted prior to canning, but some small fish (e.g. sardines) are only decapitated

Decapitation

Decapitation is the separation of the head from the body. Beheading typically refers to the act of intentional decapitation, e.g., as a means of murder or execution; it may be accomplished, for example, with an axe, sword, knife, wire, or by other more sophisticated means such as a guillotine...

and gutted prior to canning.

Consumption

Seafood is consumed all over the world; it provides the world's prime source of high-quality protein

Protein

: 14–16% of the animal protein consumed world-wide; over one billion people rely on seafood as their primary source of animal protein. Fish is among the most common food allergens

Food allergy

A food allergy is an adverse immune response to a food protein. They are distinct from other adverse responses to food, such as food intolerance, pharmacological reactions, and toxin-mediated reactions....

.

Iceland

Iceland

Iceland , described as the Republic of Iceland, is a Nordic and European island country in the North Atlantic Ocean, on the Mid-Atlantic Ridge. Iceland also refers to the main island of the country, which contains almost all the population and almost all the land area. The country has a population...

, Japan

Japan

Japan is an island nation in East Asia. Located in the Pacific Ocean, it lies to the east of the Sea of Japan, China, North Korea, South Korea and Russia, stretching from the Sea of Okhotsk in the north to the East China Sea and Taiwan in the south...

, and Portugal

Portugal

Portugal , officially the Portuguese Republic is a country situated in southwestern Europe on the Iberian Peninsula. Portugal is the westernmost country of Europe, and is bordered by the Atlantic Ocean to the West and South and by Spain to the North and East. The Atlantic archipelagos of the...

are the greatest consumers of seafood per capita in the world.

The UK Food Standards Agency

Food Standards Agency

The Food Standards Agency is a non-ministerial government department of the Government of the United Kingdom. It is responsible for protecting public health in relation to food throughout the United Kingdom and is led by a board appointed to act in the public interest...

recommends that at least two portions of seafood should be consumed each week, one of which should be oil-rich. There are over 100 different types of seafood available around the coast of the UK.

Oil-rich fish such as mackerel

Mackerel

or herring

Herring

are rich in long chain Omega-3 oils. These oils are found in every cell of the human body, and are required for human biological functions such as brain functionality.

Whitefish such as haddock and cod are very low in fat and calories which, combined with oily fish rich in Omega-3 such as mackerel

Mackerel

, sardines, fresh tuna

Tuna

, salmon

Salmon

and trout

Trout

Trout is the name for a number of species of freshwater and saltwater fish belonging to the Salmoninae subfamily of the family Salmonidae. Salmon belong to the same family as trout. Most salmon species spend almost all their lives in salt water...

, can help to protect against coronary heart disease

Coronary heart disease

Coronary artery disease is the end result of the accumulation of atheromatous plaques within the walls of the coronary arteries that supply the myocardium with oxygen and nutrients. It is sometimes also called coronary heart disease...

, as well as helping to develop strong bones and teeth.

Shellfish

Shellfish

are particularly rich in zinc

Zinc

Zinc , or spelter , is a metallic chemical element; it has the symbol Zn and atomic number 30. It is the first element in group 12 of the periodic table. Zinc is, in some respects, chemically similar to magnesium, because its ion is of similar size and its only common oxidation state is +2...

, which is essential for healthy skin and muscles as well as fertility. Casanova reputedly ate 50 oysters a day.

Health benefits

Research over the past few decades has shown that the nutrients and minerals in seafood can make improvements in brain development and reproduction and has highlighted the role for seafood in the functionality of the human body.

Heart

Doctors have known of strong links between fish and healthy hearts ever since they noticed that fish-eating Inuit populations in the Arctic had low levels of heart disease

Heart disease

Heart disease, cardiac disease or cardiopathy is an umbrella term for a variety of diseases affecting the heart. , it is the leading cause of death in the United States, England, Canada and Wales, accounting for 25.4% of the total deaths in the United States.-Types:-Coronary heart disease:Coronary...

. One study has suggested that adding one portion of fish a week to your diet can cut your chances of suffering a heart attack by half.

Fish is thought to protect the heart because eating less saturated fat

Saturated fat

Saturated fat is fat that consists of triglycerides containing only saturated fatty acids. Saturated fatty acids have no double bonds between the individual carbon atoms of the fatty acid chain. That is, the chain of carbon atoms is fully "saturated" with hydrogen atoms...

and more Omega-3 can help to lower the amount of cholesterol and triglycerides in the blood – two fats that, in excess, increase the risk of heart disease. Omega-3 fats also have natural built-in anti-oxidants, which are thought to stop the thickening and damaging of artery walls.

Regularly eating fish oils is also thought to reduce the risk of arrhythmia – irregular electrical activity in the heart which increases the risk of sudden heart attacks.

Brain

10-12% of the human brain is composed of lipid

Lipid

Lipids constitute a broad group of naturally occurring molecules that include fats, waxes, sterols, fat-soluble vitamins , monoglycerides, diglycerides, triglycerides, phospholipids, and others...

s, including the Omega-3 fat DHA

Docosahexaenoic acid

Docosahexaenoic acid is an omega-3 fatty acid that is a primary structural component of the human brain and retina. In chemical structure, DHA is a carboxylic acid with a 22-carbon chain and six cis double bonds; the first double bond is located at the third carbon from the omega end...

. Recent studies suggest that older people can boost their brain power by eating more oily fish, what with regular consumers being able to remember better and think faster than those who don't consume at all. Other research has also suggested that adding more DHA to the diet of children with attention-deficit hyperactivity disorder

Attention-deficit hyperactivity disorder

Attention deficit hyperactivity disorder is a developmental disorder. It is primarily characterized by "the co-existence of attentional problems and hyperactivity, with each behavior occurring infrequently alone" and symptoms starting before seven years of age.ADHD is the most commonly studied and...

can reduce their behavioural problems and improve their reading skills, while there have also been links suggested between DHA and better concentration. Separate studies have suggested that older people who eat fish at least once a week could also have a lower chance of developing dementia and Alzheimer's disease.

Joints

Including fish as a regular part of a balanced diet has been shown to help the symptoms of rheumatoid arthritis

Rheumatoid arthritis

Rheumatoid arthritis is a chronic, systemic inflammatory disorder that may affect many tissues and organs, but principally attacks synovial joints. The process produces an inflammatory response of the synovium secondary to hyperplasia of synovial cells, excess synovial fluid, and the development...

– a painful condition that causes joints to swell up, reducing strength and mobility. Studies also show that sufferers feel less stiff and sore in the morning if they keep their fish oil intake topped up.

Recent research has also found a link between Omega-3 fats and a slowing down in the wearing of cartilage that leads to osteoarthritis, opening the door for more research into whether eating more fish could help prevent the disease.

Minerals

Fish is high in minerals such as zinc

Zinc

, iodine

Iodine

Iodine is a chemical element with the symbol I and atomic number 53. The name is pronounced , , or . The name is from the , meaning violet or purple, due to the color of elemental iodine vapor....

and selenium

Selenium

Selenium is a chemical element with atomic number 34, chemical symbol Se, and an atomic mass of 78.96. It is a nonmetal, whose properties are intermediate between those of adjacent chalcogen elements sulfur and tellurium...

, which keep the body running smoothly. Iodine is essential for the thyroid gland, which controls growth and metabolism, while selenium is used to make enzymes that protect cell walls from cancer-causing free radicals, and helps prevent DNA damage caused by radiation and some chemicals.

Vitamins

Fish is also a source of vitamin A

Vitamin A

Vitamin A is a vitamin that is needed by the retina of the eye in the form of a specific metabolite, the light-absorbing molecule retinal, that is necessary for both low-light and color vision...

, which is needed for healthy skin and eyes, and vitamin D, which is needed to help the body absorb calcium to strengthen teeth and bones.

Mercury content

Fish

and shellfish

Shellfish

have a natural tendency to concentrate mercury

Mercury (element)

Mercury is a chemical element with the symbol Hg and atomic number 80. It is also known as quicksilver or hydrargyrum...

in their bodies, often in the form of methylmercury

Methylmercury

Methylmercury is an organometallic cation with the formula . It is a bioaccumulative environmental toxicant.-Structure:...

, a highly toxic organic compound of mercury. Species of fish that are high on the food chain

Food chain

A food web depicts feeding connections in an ecological community. Ecologists can broadly lump all life forms into one of two categories called trophic levels: 1) the autotrophs, and 2) the heterotrophs...

, such as shark

Shark

Sharks are a type of fish with a full cartilaginous skeleton and a highly streamlined body. The earliest known sharks date from more than 420 million years ago....

, swordfish

Swordfish

Swordfish , also known as broadbill in some countries, are large, highly migratory, predatory fish characterized by a long, flat bill. They are a popular sport fish of the billfish category, though elusive. Swordfish are elongated, round-bodied, and lose all teeth and scales by adulthood...

, king mackerel

King mackerel

The king mackerel is a migratory species of mackerel of the western Atlantic Ocean and Gulf of Mexico. It is an important species to both the commercial and recreational fishing industries.-Description:...

, albacore tuna, and tilefish

Tilefish

Tilefishes, also known as blanquillo, are mostly small perciform marine fish comprising the family Malacanthidae.They are usually found in sandy areas, especially near coral reefs....

contain higher concentrations of mercury than others. This is because mercury is stored in the muscle tissues of fish, and when a predatory fish eats another fish, it assumes the entire body burden of mercury in the consumed fish. Since fish are less efficient at depurating than accumulating methylmercury, fish-tissue concentrations increase over time. Thus species that are high on the food chain

Food chain

amass body burdens of mercury that can be ten times higher than the species they consume. This process is called biomagnification

Biomagnification

Biomagnification, also known as bioamplification or biological magnification, is the increase in concentration of a substance that occurs in a food chain as a consequence of:* Persistence...

. The first occurrence of widespread mercury poisoning

Mercury poisoning

Mercury poisoning is a disease caused by exposure to mercury or its compounds. Mercury is a heavy metal occurring in several forms, all of which can produce toxic effects in high enough doses...

in humans occurred this way in Minamata

Minamata, Kumamoto

is a city located in Kumamoto prefecture, Japan. It is on the west coast of Kyūshū. The city was founded on April 1, 1949.As of 2008, the city has an estimated population of 27,856 and the density of 171 persons per km²...

, Japan

Japan

, now called Minamata disease

Minamata disease

', sometimes referred to as , is a neurological syndrome caused by severe mercury poisoning. Symptoms include ataxia, numbness in the hands and feet, general muscle weakness, narrowing of the field of vision and damage to hearing and speech. In extreme cases, insanity, paralysis, coma, and death...

Overfishing

Research into population trends of various species of seafood is pointing to a global collapse of seafood species by 2048. Such a collapse would occur due to pollution and overfishing, threatening oceanic ecosystems, according to some researchers.

A major international scientific study released in November 2006 in the journal Science
Science
Science is a systematic enterprise that builds and organizes knowledge in the form of testable explanations and predictions about the universe...

found that about one-third of all fishing stocks worldwide have collapsed (with a collapse being defined as a decline to less than 10% of their maximum observed abundance), and that if current trends continue all fish stocks worldwide will collapse within fifty years. In July 2009, Boris Worm

Boris Worm

Dr. Boris Worm is a Marine Research Ecologist and Associate Professor at Dalhousie University, Canada. He has made leading scientific contributions to the fields of marine ecology and fisheries conservation. Worm was a postdoctoral fellow under the late Ransom Myers and now leads his own lab at...

of Dalhousie University

Dalhousie University

Dalhousie University is a public research university located in Halifax, Nova Scotia, Canada. The university comprises eleven faculties including Schulich School of Law and Dalhousie University Faculty of Medicine. It also includes the faculties of architecture, planning and engineering located at...

, the author of the November 2006 study in Science
Science
Science is a systematic enterprise that builds and organizes knowledge in the form of testable explanations and predictions about the universe...

, co-authored an update on the state of the world's fisheries with one of the original study's critics, Ray Hilborn

Ray Hilborn

Ray Hilborn is a marine biologist and fisheries scientist, known for his work on conservation and natural resource management in the context of fisheries.He is currently professor of aquatic and fishery science at the University of Washington...

of the University of Washington

University of Washington

University of Washington is a public research university, founded in 1861 in Seattle, Washington, United States. The UW is the largest university in the Northwest and the oldest public university on the West Coast. The university has three campuses, with its largest campus in the University...

at Seattle. The new study found that through good fisheries management techniques even depleted fish stocks can be revived and made commercially viable again.

The FAO

Fão

Fão is a town in Esposende Municipality in Portugal....

State of World Fisheries and Aquaculture 2004 report estimates that in 2003, of the main fish stocks or groups of resources for which assessment information is available, "approximately one-quarter were overexploited, depleted or recovering from depletion (16%, 7% and 1% respectively) and needed rebuilding."

The National Fisheries Institute

National Fisheries Institute

The National Fisheries Institute is the United States industry trade group representing the seafood industry. It is a member of the International Coalition of Fisheries Associations . Its member companies consist of all levels of business involved in seafood, from fishing vessel operators to...

, a trade advocacy group representing the United States seafood industry, disagree. They claim that currently observed declines in fish population are due to natural fluctuations and that enhanced technologies will eventually alleviate whatever impact humanity is having on oceanic life.

External links

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