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Aquaculture (less commonly spelled aquiculture), also known as aquafarming, is the farming of
fish Fish are , , -bearing animals that lack with . Included in this definition are the living , s, and and as well as various extinct related groups. Around 99% of living fish species are ray-finned fish, belonging to the class , with over 95 ...

fish
,
crustacean Crustaceans (Crustacea ) form a large, diverse arthropod An arthropod (, (gen. ποδός)) is an invertebrate Invertebrates are animals that neither possess nor develop a vertebral column (commonly known as a ''backbone'' or ''spine''), der ...
s,
mollusk Mollusca is the second-largest phylum In biology, a phylum (; plural The plural (sometimes list of glossing abbreviations, abbreviated ), in many languages, is one of the values of the grammatical number, grammatical category of number ...
s,
aquatic plant Aquatic plants are plant Plants are predominantly photosynthetic eukaryotes of the Kingdom (biology), kingdom Plantae. Historically, the plant kingdom encompassed all living things that were not animals, and included algae and fungi; howeve ...
s,
algae Algae (; singular alga ) is an informal term for a large and diverse group of s. It is a grouping that includes species from multiple distinct s. Included organisms range from , such as '','' and the s, to forms, such as the , a large whi ...

algae
, and other organisms. Aquaculture involves cultivating freshwater and saltwater populations under controlled conditions, and can be contrasted with
commercial fishing Commercial fishing is the activity of catching and other for , mostly from . It provides a large quantity of food to many countries around the earth, but those who practice it as an industry must often pursue fish far into the ocean under adver ...

commercial fishing
, which is the harvesting of
wild fish A fishery Fishery is the enterprise of raising or harvesting fish and other aquatic life. Commercial fisheries include wild fisheries and Fish farming, fish farms, both in fresh water (about 10% of all catch) and the oceans (about 90%). About 500 ...
.
Mariculture Fish cages containing salmon in Sound of Arisaig, Loch Ailort, Scotland. Mariculture is a specialized branch of aquaculture (which includes freshwater aquaculture) involving the cultivation of marine organisms for food and other products in the op ...
commonly known as marine farming refers to aquaculture practiced in marine environments and in underwater habitats, opposed to in freshwater. According to the Food and Agriculture Organization (FAO), aquaculture "is understood to mean the farming of aquatic organisms including fish, molluscs, crustaceans and aquatic plants. Farming implies some form of intervention in the rearing process to enhance production, such as regular stocking, feeding, protection from predators, etc. Farming also implies individual or corporate ownership of the stock being cultivated." The reported output from global aquaculture operations in 2014 supplied over one half of the fish and shellfish that is directly consumed by humans; however, there are issues about the reliability of the reported figures. Further, in current aquaculture practice, products from several pounds of wild fish are used to produce one pound of a
piscivorous (''Nerodia sipedon'') eating a fish A piscivore is a carnivore, carnivorous animal that eats primarily fish Fish are Aquatic animal, aquatic, craniate, gill-bearing animals that lack Limb (anatomy), limbs with Digit (anatomy), digits. Th ...
fish like
salmon Salmon is the common name for several species of ray-finned fish Actinopterygii ( New Latin ('having rays') + Greek ( 'wing, fins')), members of which are known as ray-finned fishes, is a clade A clade (; from grc, , ''klados'', " ...
. Particular kinds of aquaculture include
fish farming upright=1.3, Salmon farming in the sea (mariculture) at Loch Ainort, Isle of Skye">mariculture.html" ;"title="Salmon farming in the sea (mariculture">Salmon farming in the sea (mariculture) at Loch Ainort, Isle of Skye, Scotland Fish farming or ...

fish farming
,
shrimp farm Shrimp farming is an aquaculture Aquaculture (less commonly spelled aquiculture), also known as aquafarming, is the farming of fish, crustaceans, mollusks, aquatic plants, algae, and other organisms. Aquaculture involves cultivating freshwater ...
ing,
oyster farming Oyster farming is an aquaculture Aquaculture (less commonly spelled aquiculture), also known as aquafarming, is the farming of fish, crustaceans, mollusks, aquatic plants, algae, and other organisms. Aquaculture involves cultivating freshwater ...
,
mariculture Fish cages containing salmon in Sound of Arisaig, Loch Ailort, Scotland. Mariculture is a specialized branch of aquaculture (which includes freshwater aquaculture) involving the cultivation of marine organisms for food and other products in the op ...
,
algaculture Algaculture is a form of aquaculture Aquaculture (less commonly spelled aquiculture), also known as aquafarming, is the farming of fish Fish are Aquatic animal, aquatic, craniate, gill-bearing animals that lack Limb (anatomy), limbs wit ...
(such as
seaweed farming Seaweed farming or kelp farming is the practice of cultivating and harvesting seaweed. In its simplest form, it consists of the management of naturally found batches. In its most advanced form, it consists of fully controlling the life cycle of t ...
), and the cultivation of
ornamental fish Lists of aquarium life include lists of fish Fish are Aquatic animal, aquatic, craniate, gill-bearing animals that lack Limb (anatomy), limbs with Digit (anatomy), digits. They form a sister group to the tunicates, together forming the Chorda ...
. Particular methods include
aquaponics Aquaponics refers to a food production system that couples aquaculture Aquaculture (less commonly spelled aquiculture), also known as aquafarming, is the farming of fish, crustaceans, mollusks, aquatic plants, algae, and other organisms. Aqu ...

aquaponics
and
integrated multi-trophic aquaculture Integrated multi-trophic aquaculture (IMTA) provides the byproducts, including waste, from one aquatic species as inputs (fertilizer A fertilizer (American English American English (AmE, AE, AmEng, USEng, en-US), sometimes called Unit ...
, both of which integrate fish farming and aquatic plant farming. The
Food and Agriculture Organization The Food and Agriculture Organization of the United Nations (FAO)french: Organisation des Nations unies pour l'alimentation et l'agriculture; it, Organizzazione delle Nazioni Unite per l'Alimentazione e l'Agricoltura is a list of specialized ...
describes aquaculture as one of the industries most directly affected by climate change and its impacts. Some forms of aquaculture, such as seaweed farming, have the opportunity to be part of climate change mitigation, while other forms of aquaculture have negative impacts on the environment, such as through nutrient pollution or disease transfer to wild populations.


History

The
Gunditjmara The Gunditjmara or Gunditjamara, also known as Dhauwurd Wurrung, are an Aboriginal Australian Aboriginal Australians are the various Indigenous peoples Indigenous peoples, also referred to as First people, Aboriginal people, Native peop ...
, the local
Aboriginal Australian people Aboriginal Australians are the various Indigenous peoples of the Mainland Australia, Australian mainland and many of its islands, such as Tasmania, Fraser Island, Hinchinbrook Island, the Tiwi Islands, and Groote Eylandt, but excluding the Torr ...
in south-western
Victoria Victoria most commonly refers to: * Victoria (Australia), a state of the Commonwealth of Australia * Victoria, British Columbia, provincial capital of British Columbia, Canada * Victoria (mythology), Roman goddess of Victory * Victoria, Seychelles ...
, Australia, may have raised
short-finned eel The short-finned eel (''Anguilla australis''), also known as the shortfin eel, is one of the 15 species of eel in the family Anguillidae. It is native to the lakes, dams and coastal rivers of south-eastern Australia, New Zealand, and much of the ...
s as early as about 4,580
BCE Common Era (CE) is one of the year notations used for the Gregorian calendar The Gregorian calendar is the used in most of the world. It was introduced in October 1582 by as a modification of the , reducing the average year from 365.2 ...

BCE
(6,530 years BP). See also attached documents: National Heritage List ''Location and Boundary Map'', and ''Government Gazette'', 20 July 2004. Evidence indicates they developed about of volcanic
floodplain File:Flood plain 7991.JPG, Riparian vegetation on the floodplain of the Lynches River, close to Johnsonville, South Carolina. These tupelo and Taxodium, cypress trees show the ordinary high water mark, high-water mark of flooding. A floodpl ...
s in the vicinity of
Lake Condah Lake Condah, also known by its Gunditjmara language, Gunditjmara name Tae Rak, is in the Australian state of Victoria, Australia, Victoria, about west of Melbourne and north-east of Heywood, Victoria, Heywood by road. It is in the form of a sha ...
into a complex of channels and dams, and used woven traps to capture
eel Eels are ray-finned fish Actinopterygii ( New Latin ('having rays') + Greek ( 'wing, fins')), members of which are known as ray-finned fishes, is a clade A clade (; from grc, , ''klados'', "branch"), also known as a monophyletic gro ...
s, and preserve them to eat all year round. The Budj Bim Cultural Landscape, a
World Heritage Site A World Heritage Site is a landmark or area with legal protection by an international convention administered by the United Nations Educational, Scientific and Cultural Organization (UNESCO). World Heritage Sites are designated by UNESCO for h ...
, is thought to be one of the oldest aquaculture sites in the world.
Oral tradition Oral tradition, or oral lore, is a form of human communication Human communication, or anthroposemiotics, is the field dedicated to understanding how human Humans (''Homo sapiens'') are the most populous and widespread species of prima ...
in China tells of the culture of the common carp, ''
Cyprinus carpio The common carp or European carp (''Cyprinus carpio'') is a widespread freshwater fish Fish are Aquatic animal, aquatic, craniate, gill-bearing animals that lack Limb (anatomy), limbs with Digit (anatomy), digits. They form a sister group t ...

Cyprinus carpio
'', as long ago as 2000–2100
BCE Common Era (CE) is one of the year notations used for the Gregorian calendar The Gregorian calendar is the used in most of the world. It was introduced in October 1582 by as a modification of the , reducing the average year from 365.2 ...

BCE
(around 4,000 years BP), but the earliest significant evidence lies in the literature, in the earliest monograph on fish culture called ''The Classic of Fish Culture'', by
Fan Li Fan Li () from the Spring and Autumn period#REDIRECT Spring and Autumn period The Spring and Autumn period was a period in Chinese history The earliest known written records of the history of China date from as early as 1250 BC, from th ...
, written around 475
BCE Common Era (CE) is one of the year notations used for the Gregorian calendar The Gregorian calendar is the used in most of the world. It was introduced in October 1582 by as a modification of the , reducing the average year from 365.2 ...

BCE
(c.2475 BP). Another ancient Chinese guide to aquaculture was by Yang Yu Jing, written around 460
BCE Common Era (CE) is one of the year notations used for the Gregorian calendar The Gregorian calendar is the used in most of the world. It was introduced in October 1582 by as a modification of the , reducing the average year from 365.2 ...

BCE
, showing that carp farming was becoming more sophisticated. The
Jiahu Jiahu () was the site of a Neolithic settlement based in the central plain of ancient China, near the Yellow River. It is located between the floodplains of the Ni River (China), Ni River to the north, and the Sha River to the south, north of ...

Jiahu
site in China has circumstantial archeological evidence as possibly the oldest aquaculture locations, dating from 6200
BCE Common Era (CE) is one of the year notations used for the Gregorian calendar The Gregorian calendar is the used in most of the world. It was introduced in October 1582 by as a modification of the , reducing the average year from 365.2 ...

BCE
(about 8,200 years BP), but this is speculative. When the waters subsided after river floods, some fish, mainly
carp Carp are various species of from the family , a very large group of native to and . While carp is consumed in many parts of the world, they are generally considered an in parts of Africa, Australia and most of the United States. Biology The ...

carp
, were trapped in lakes. Early aquaculturists fed their brood using
nymphs A nymph ( grc, νύμφη, nýmphē, el, script=Latn, nímfi, label=Modern Greek Modern Greek (, , or , ''Kiní Neoellinikí Glóssa''), generally referred to by speakers simply as Greek (, ), refers collectively to the dialects of the Gree ...
and
silkworm ''Bombyx mori'', the domestic silk moth, is an insect from the moth Moths are a paraphyletic In taxonomy, a group is paraphyletic if it consists of the group's last common ancestor and all descendants of that ancestor excluding a ...

silkworm
faeces, and ate them.
Ancient Egyptians Ancient Egypt was a civilization  A civilization (or civilisation) is a complex society A complex society is a concept that is shared by a range of disciplines including anthropology, archaeology, history and sociology to descri ...
might have farmed fish (especially
Gilt-head bream The gilt-head (sea) bream (''Sparus aurata''), called Orata in antiquity and still today in Italy (while in Spain is "Dorada"), is a fish of the bream family Sparidae found in the Mediterranean Sea The Mediterranean Sea is a sea connected t ...

Gilt-head bream
) from Lake Bardawil about 1,500
BCE Common Era (CE) is one of the year notations used for the Gregorian calendar The Gregorian calendar is the used in most of the world. It was introduced in October 1582 by as a modification of the , reducing the average year from 365.2 ...

BCE
(3,520 years BP), and they traded them with
Canaan A 1692 map of Canaan, by Philip Lea Canaan (; Northwest Semitic Northwest Semitic, known as Syro-Palestinian in dialect geography, is a division of the Semitic languages comprising the indigenous languages of the Levant. It would have ...

Canaan
. '' Gim'' cultivation is the oldest aquaculture in
Korea Korea is a region In geography, regions are areas that are broadly divided by physical characteristics (physical geography), human impact characteristics (human geography), and the interaction of humanity and the environment (environmental ...

Korea
. Early cultivation methods used
bamboo Bamboos are a diverse group of evergreen In botany Botany, also called , plant biology or phytology, is the science of plant life and a branch of biology. A botanist, plant scientist or phytologist is a scientist who specialises in th ...

bamboo
or
oak An oak is a tree In botany, a tree is a perennial plant with an elongated Plant stem, stem, or trunk (botany), trunk, supporting branches and leaves in most species. In some usages, the definition of a tree may be narrower, including on ...

oak
sticks, which were replaced by newer methods that utilized nets in the 19th century. Floating rafts have been used for mass production since the 1920s. Japanese cultivated
seaweed Seaweed, or macroalgae, refers to thousands of species of , , . The term includes some types of ' (red), ' (brown) and ' (green) macroalgae. Seaweed species such as s provide essential nursery habitat for fisheries and other marine species an ...

seaweed
by providing
bamboo Bamboos are a diverse group of evergreen In botany Botany, also called , plant biology or phytology, is the science of plant life and a branch of biology. A botanist, plant scientist or phytologist is a scientist who specialises in th ...

bamboo
poles and, later, nets and
oyster Oyster is the common name Common may refer to: Places * Common, a townland in County Tyrone, Northern Ireland * Boston Common Boston Common (also known as the Common) is a central public park in downtown Boston, Massachusetts. It is someti ...

oyster
shells to serve as anchoring surfaces for
spore )'', growing on a thinning, thinned hybrid black poplar ''(populus, Populus x canadensis)''. The last stage of the moss#Life cycle, moss lifecycle is shown, where the sporophytes are visible before dispersion of their spores: the calyptra (1) is ...
s.
Romans Roman or Romans usually refers to: *Rome , established_title = Founded , established_date = 753 BC , founder = King Romulus , image_map = Map of comune of Rome (metropolitan city of Capital Rome, region Lazio, ...
bred fish in ponds and farmed oysters in coastal lagoons before 100 CE. In central Europe, early Christian
monasteries A monastery is a building or complex of buildings comprising the domestic quarters and workplaces of monastics, monk A monk (, from el, μοναχός, ''monachos'', "single, solitary" via Latin Latin (, or , ) is a classical langua ...

monasteries
adopted Roman aquacultural practices. Aquaculture spread in Europe during the
Middle Ages In the history of Europe The history of Europe concerns itself with the discovery and collection, the study, organization and presentation and the interpretation of past events and affairs of the people of Europe since the beginning of ...
since away from the seacoasts and the big rivers, fish had to be salted so they did not rot. Improvements in transportation during the 19th century made fresh fish easily available and inexpensive, even in inland areas, making aquaculture less popular. The 15th-century fishponds of the Trebon Basin in the
Czech Republic The Czech Republic, also known by its short-form name Czechia and formerly known as Bohemia, is a landlocked country in Central Europe. It is bordered by Austria to the south, Germany to the west, Poland to the northeast, and Slovakia to ...
are maintained as a
UNESCO World Heritage Site A World Heritage Site is a landmark or area with legal protection by an international convention administered by the UNESCO, United Nations Educational, Scientific and Cultural Organization (UNESCO). World Heritage Sites are designated by UNES ...
.
Hawaii Hawaii ( ; haw, Hawaii or ) is a state State may refer to: Arts, entertainment, and media Literature * ''State Magazine'', a monthly magazine published by the U.S. Department of State * The State (newspaper), ''The State'' (newspape ...

Hawaii
ans constructed oceanic fish ponds. A remarkable example is the "Menehune" fishpond dating from at least 1,000 years ago, at Alekoko. Legend says that it was constructed by the mythical
Menehune Menehune are a mythological race of dwarf Dwarf or dwarves may refer to: Common uses *Dwarf (folklore), a being from Germanic mythology and folklore * Dwarf, a person or animal with dwarfism * Dwarf to describe a small person Arts, enterta ...
dwarf people. In the first half of the 18th century, German Stephan Ludwig Jacobi experimented with
external fertilization External fertilization is a mode of reproduction Reproduction (or procreation or breeding) is the biological process Biological processes are those processes that are vital for an organism In biology, an organism (from Ancient Greek ...
of
brown trout The brown trout (''Salmo trutta'') is a European species of salmonid fish that has been widely introduced into suitable environments globally. It includes purely freshwater populations, referred to as the riverine ecotype, ''Salmo trutta'' Morph ...

brown trout
s and
salmon Salmon is the common name for several species of ray-finned fish Actinopterygii ( New Latin ('having rays') + Greek ( 'wing, fins')), members of which are known as ray-finned fishes, is a clade A clade (; from grc, , ''klados'', ...

salmon
. He wrote an article ''"Von der künstlichen Erzeugung der Forellen und Lachse"'' (''On the Artificial Production of Trout and Salmon'') summarizing his findings, and is regarded as the founder of artificial fish rearing in Europe. By the latter decades of the 18th century, oyster farming had begun in estuaries along the Atlantic Coast of North America. The word aquaculture appeared in an 1855 newspaper article in reference to the harvesting of ice. It also appeared in descriptions of the terrestrial agricultural practise of sub-irrigation in the late 19th century before becoming associated primarily with the cultivation of aquatic plant and animal species. In 1859, Stephen Ainsworth of
West Bloomfield, New York West Bloomfield is a town A town is a human settlement. Towns are generally larger than villages and smaller than city, cities, though the criteria to distinguish between them vary considerably in different parts of the world. Origin ...
, began experiments with
brook trout The brook trout (''Salvelinus fontinalis'') is a species In biology, a species is the basic unit of biological classification, classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined ...

brook trout
. By 1864, Seth Green had established a commercial fish-hatching operation at Caledonia Springs, near
Rochester, New York Rochester () is a city A city is a large human settlement.Goodall, B. (1987) ''The Penguin Dictionary of Human Geography''. London: Penguin.Kuper, A. and Kuper, J., eds (1996) ''The Social Science Encyclopedia''. 2nd edition. London: Routle ...

Rochester, New York
. By 1866, with the involvement of Dr. W. W. Fletcher of
Concord, Massachusetts Concord () is a town in Middlesex County, Massachusetts Middlesex County is located in the Commonwealth of Massachusetts Massachusetts (, ), officially the Commonwealth of Massachusetts, is the most populous U.S. state, state in the New E ...
, artificial fish hatcheries were underway in both Canada and the United States. When the
Dildo Island Dildo Island is an island in the Canadian province of Newfoundland and Labrador. It is the largest of three islands located at the entrance to Dildo Tip in the bottom of Trinity Bay (Newfoundland), Trinity Bay, off the coast of the neighbouring t ...
fish hatchery opened in Newfoundland in 1889, it was the largest and most advanced in the world. The word aquaculture was used in descriptions of the hatcheries experiments with cod and lobster in 1890. By the 1920s, the American Fish Culture Company of
Carolina, Rhode Island Carolina is a village that straddles the border of the towns of Charlestown and Richmond on the Pawcatuck River in Washington County, Rhode Island, Washington County, Rhode Island. Rhode Island Route 112 passes through the village. Carolina is id ...
, founded in the 1870s was one of the leading producers of trout. During the 1940s, they had perfected the method of manipulating the day and night cycle of fish so that they could be artificially spawned year around. Californians harvested wild
kelp Kelps are large brown algae The brown algae (singular: alga), comprising the class (biology), class Phaeophyceae, are a large group of multicellular algae, including many seaweeds located in colder waters within the Northern Hemisphere. Most b ...

kelp
and attempted to manage supply around 1900, later labeling it a wartime resource.


21st-century practice

Harvest stagnation in
wild fisheries A wild fishery is a natural Nature, in the broadest sense, is the natural, physical, material world or universe The universe ( la, universus) is all of space and time and their contents, including planets, stars, galaxies, and al ...
and
overexploitation Overexploitation, also called overharvesting, refers to harvesting a renewable resource File:Global Vegetation.jpg, Global vegetation A renewable resource, also known as a flow resource, is a natural resource which will replenish to replace th ...

overexploitation
of popular marine species, combined with a growing demand for high-quality protein, encouraged aquaculturists to domesticate other marine species.The Case for Fish and Oyster Farming
," Carl Marziali, University of Southern California Trojan Family Magazine, May 17, 2009.
At the outset of modern aquaculture, many were optimistic that a "Blue Revolution" could take place in aquaculture, just as the
Green Revolution The Green Revolution, or the Third Agricultural Revolution (after the Neolithic Revolution The Neolithic Revolution, or the (First) Agricultural Revolution, was the wide-scale transition of many human culture Culture () is an umbrel ...

Green Revolution
of the 20th century had revolutionized agriculture. Although land animals had long been domesticated, most seafood species were still caught from the wild. Concerned about the impact of growing demand for seafood on the world's oceans, prominent ocean explorer
Jacques Cousteau Jacques-Yves Cousteau, (, also , ; 11 June 191025 June 1997) was a French naval officer, explorer, Conservation movement, conservationist, filmmaker, scientist, photographer, author and researcher who studied the sea and all forms of life in w ...
wrote in 1973: "With earth's burgeoning human populations to feed, we must turn to the sea with new understanding and new technology." About 430 (97%) of the species cultured were domesticated during the 20th and 21st centuries, of which an estimated 106 came in the decade to 2007. Given the long-term importance of agriculture, to date, only 0.08% of known land plant species and 0.0002% of known land animal species have been domesticated, compared with 0.17% of known marine plant species and 0.13% of known marine animal species. Domestication typically involves about a decade of scientific research. Domesticating aquatic species involves fewer risks to humans than do land animals, which took a large toll in human lives. Most major human diseases originated in domesticated animals, including diseases such as
smallpox Smallpox was an infectious disease An infection is the invasion of an organism's body Tissue (biology), tissues by Pathogen, disease-causing agents, their multiplication, and the reaction of host (biology), host tissues to the infectious ...

smallpox
and
diphtheria Diphtheria is an infection caused by the bacteria, bacterium ''Corynebacterium diphtheriae''. Most infections are asymptomatic or have a mild Course (medicine), clinical course, but in some outbreaks more than 10% of those diagnosed with the di ...

diphtheria
, that like most infectious diseases, move to humans from animals. No human
pathogen In biology, a pathogen ( el, πάθος, "suffering", "passion" and , "producer of") in the oldest and broadest sense, is any organism that can produce disease. A pathogen may also be referred to as an infectious agent, or simply a Germ theory ...
s of comparable virulence have yet emerged from marine species. Biological control methods to manage parasites are already being used, such as cleaner fish (e.g. lumpsuckers and wrasse) to control sea lice populations in salmon farming. Models are being used to help with spatial planning and siting of fish farms in order to minimize impact. The decline in wild fish stocks has increased the demand for farmed fish. However, finding alternative sources of protein and oil for fish feed is necessary so the aquaculture industry can grow sustainably; otherwise, it represents a great risk for the over-exploitation of forage fish. Another recent issue following the banning in 2008 of organotins by the International Maritime Organization is the need to find environmentally friendly, but still effective, compounds with antifouling effects. Many new natural compounds are discovered every year, but producing them on a large enough scale for commercial purposes is almost impossible. It is highly probable that future developments in this field will rely on microorganisms, but greater funding and further research is needed to overcome the lack of knowledge in this field.


Species groups


Aquatic plants

Microalgae Microalgae or microphytes are microscopic The microscopic scale (from , ''mikrós'', "small" and σκοπέω, ''skopéō'' "look") is the scale of objects and events smaller than those that can easily be seen by the naked eye Naked eye, ...
, also referred to as
phytoplankton Phytoplankton () are the autotrophic An autotroph or primary producer is an organism that produces complex organic compound , CH4; is among the simplest organic compounds. In chemistry, organic compounds are generally any chemical compoun ...

phytoplankton
, microphytes, or planktonic algae, constitute the majority of cultivated
algae Algae (; singular alga ) is an informal term for a large and diverse group of s. It is a grouping that includes species from multiple distinct s. Included organisms range from , such as '','' and the s, to forms, such as the , a large whi ...

algae
. Macroalgae commonly known as
seaweed Seaweed, or macroalgae, refers to thousands of species of , , . The term includes some types of ' (red), ' (brown) and ' (green) macroalgae. Seaweed species such as s provide essential nursery habitat for fisheries and other marine species an ...

seaweed
also have many commercial and industrial uses, but due to their size and specific requirements, they are not easily cultivated on a large scale and are most often taken in the wild. In 2016, aquaculture was the source of 96.5 percent by volume of the total 31.2 million tonnes of wild-collected and cultivated aquatic plants combined. Global production of farmed aquatic plants, overwhelmingly dominated by seaweeds, grew in output volume from 13.5 million tonnes in 1995 to just over 30 million tonnes in 2016.


Seaweed farming


Fish

The farming of fish is the most common form of aquaculture. It involves raising fish commercially in tanks,
fish pond A fish pond, or fishpond, is a controlled pond A pond is an area filled with water, either natural or artificial, that is smaller than a lake A lake is an area filled with water, localized in a basin, surrounded by land, apart from an ...

fish pond
s, or ocean enclosures, usually for food. A facility that releases juvenile fish into the wild for recreational fishing or to supplement a species' natural numbers is generally referred to as a fish
hatchery Salmon Hatchery, near Inchnadamph in the Scottish Highlands. A hatchery is a facility where Egg (biology), eggs are hatched under artificial conditions, especially those of fish, poultry or even turtles. It may be used for ex-situ conservation ...

hatchery
. Worldwide, the most important fish species used in fish farming are, in order,
carp Carp are various species of from the family , a very large group of native to and . While carp is consumed in many parts of the world, they are generally considered an in parts of Africa, Australia and most of the United States. Biology The ...

carp
,
salmon Salmon is the common name for several species of ray-finned fish Actinopterygii ( New Latin ('having rays') + Greek ( 'wing, fins')), members of which are known as ray-finned fishes, is a clade A clade (; from grc, , ''klados'', ...

salmon
,
tilapia Tilapia ( ) is the common name Common may refer to: Places * Common, a townland in County Tyrone, Northern Ireland * Boston Common Boston Common (also known as the Common) is a central public park in downtown Boston, Massachusetts. It is s ...

tilapia
, and
catfish Catfish (or catfishes; order Order or ORDER or Orders may refer to: * Orderliness Orderliness is associated with other qualities such as cleanliness Cleanliness is both the abstract state of being clean and free from germs, dirt, trash, o ...

catfish
. In the Mediterranean, young
bluefin tuna Bluefin tuna is a common name used to refer to several species of tuna A tuna is a saltwater fish Fish are Aquatic animal, aquatic, craniate, gill-bearing animals that lack Limb (anatomy), limbs with Digit (anatomy), digits. They form ...
are netted at sea and towed slowly towards the shore. They are then interned in offshore pens (sometimes made from floating HDPE pipe) where they are further grown for the market. In 2009, researchers in Australia managed for the first time to coax
southern bluefin tuna The southern bluefin tuna (''Thunnus maccoyii'') is a tuna of the family (biology), family Scombridae found in open southern Hemisphere waters of all the world's oceans mainly between 30th parallel south, 30°S and 50th parallel south, 50°S, to ...
to breed in landlocked tanks. Southern bluefin tuna are also caught in the wild and fattened in grow-out sea cages in southern
Spencer Gulf The Spencer Gulf is the westernmost and larger of two large inlets (the other being Gulf St Vincent) on the southern coast of Australia, in the state of South Australia, facing the Great Australian Bight. It spans from the Cape Catastrophe and ...

Spencer Gulf
,
South Australia South Australia (abbreviated as SA) is a States and territories of Australia, state in the southern central part of Australia. It covers some of the most arid parts of the country. With a total land area of , it is the fourth-largest of Austral ...

South Australia
. A similar process is used in the salmon-farming section of this industry; juveniles are taken from hatcheries and a variety of methods are used to aid them in their maturation. For example, as stated above, some of the most important fish species in the industry, salmon, can be grown using a cage system. This is done by having netted cages, preferably in open water that has a strong flow, and feeding the salmon a special food mixture that aids their growth. This process allows for year-round growth of the fish, thus a higher harvest during the correct seasons. An additional method, known sometimes as sea ranching, has also been used within the industry. Sea ranching involves raising fish in a
hatchery Salmon Hatchery, near Inchnadamph in the Scottish Highlands. A hatchery is a facility where Egg (biology), eggs are hatched under artificial conditions, especially those of fish, poultry or even turtles. It may be used for ex-situ conservation ...

hatchery
for a brief time and then releasing them into marine waters for further development, whereupon the fish are recaptured when they have matured.


Crustaceans

Commercial
shrimp Shrimp are Decapoda, decapod crustaceans with elongated bodies and a primarily swimming mode of locomotion – most commonly Caridea and Dendrobranchiata. More narrow definitions may be restricted to Caridea, to smaller species of either group ...

shrimp
farming began in the 1970s, and production grew steeply thereafter. Global production reached more than 1.6 million tonnes in 2003, worth about US$9 billion. About 75% of farmed shrimp is produced in Asia, in particular in China and Thailand. The other 25% is produced mainly in Latin America, where Brazil is the largest producer. Thailand is the largest exporter. Shrimp farming has changed from its traditional, small-scale form in Southeast Asia into a global industry. Technological advances have led to ever higher densities per unit area, and
broodstockBroodstock, or broodfish, are a group of mature individuals used in aquaculture Aquaculture (less commonly spelled aquiculture), also known as aquafarming, is the farming of fish, crustaceans, mollusks, aquatic plants, algae, and other organisms ...
is shipped worldwide. Virtually all farmed shrimp are penaeids (i.e., shrimp of the
family In human society A society is a Social group, group of individuals involved in persistent Social relation, social interaction, or a large social group sharing the same spatial or social territory, typically subject to the same Politic ...
Penaeidae Penaeidae is a family of marine crustaceans in the suborder Dendrobranchiata, which are often referred to as penaeid shrimp or penaeid prawns. The Penaeidae contain many species of economic importance, such as the tiger prawn, whiteleg shrimp, At ...
), and just two species of shrimp, the Pacific white shrimp and the
giant tiger prawn ''Penaeus monodon'', commonly known as the giant tiger prawn,Asian tiger shrimp, black tiger shrimp, and other names, is a marine crustacean Crustaceans (Crustacea ) form a large, diverse arthropod An arthropod (, (gen. ποδός)) is an inv ...
, account for about 80% of all farmed shrimp. These industrial monocultures are very susceptible to disease, which has decimated shrimp populations across entire regions. Increasing ecology, ecological problems, repeated disease outbreaks, and pressure and criticism from both nongovernmental organizations and consumer countries led to changes in the industry in the late 1990s and generally stronger regulations. In 1999, governments, industry representatives, and environmental organizations initiated a program aimed at developing and promoting more sustainable agriculture, sustainable farming practices through the Seafood Watch program. Freshwater prawn farming shares many characteristics with, including many problems with, marine shrimp farming. Unique problems are introduced by the developmental lifecycle of the main species, the giant river prawn.New, M. B.:
Farming Freshwater Prawns
'; FAO Fisheries Technical Paper 428, 2002. .
The global annual production of freshwater prawns (excluding crayfish and crabs) in 2007 was about 460,000 tonnes, exceeding 1.86 billion dollars. Additionally, China produced about 370,000 tonnes of Chinese river crab.Data extracted from th
FAO Fisheries Global Aquaculture Production Database
for freshwater crustaceans. The most recent data are from 2003 and sometimes contain estimates. Retrieved June 28, 2005.
In addition astaciculture is the freshwater farming of crayfish (mostly in the US, Australia, and Europe).


Molluscs

Aquacultured shellfish include various
oyster Oyster is the common name Common may refer to: Places * Common, a townland in County Tyrone, Northern Ireland * Boston Common Boston Common (also known as the Common) is a central public park in downtown Boston, Massachusetts. It is someti ...

oyster
, mussel, and clam species. These bivalves are filter and/or deposit feeders, which rely on ambient primary production rather than inputs of fish or other feed. As such, shellfish aquaculture is generally perceived as benign or even beneficial. Depending on the species and local conditions, bivalve molluscs are either grown on the beach, on longlines, or suspended from rafts and harvested by hand or by dredging. In May 2017 a Belgian consortium installed the first of two trial mussel farms on a wind farm in the North Sea. Abalone farming began in the late 1950s and early 1960s in Japan and China. Since the mid-1990s, this industry has become increasingly successful. Overfishing and poaching have reduced wild populations to the extent that farmed abalone now supplies most abalone meat. Sustainably farmed molluscs can be certified by Seafood Watch and other organizations, including the World Wildlife Fund (WWF). WWF initiated the "Aquaculture Dialogues" in 2004 to develop measurable and performance-based standards for responsibly farmed seafood. In 2009, WWF co-founded the Aquaculture Stewardship Council with the Dutch Sustainable Trade Initiative to manage the global standards and certification programs. After trials in 2012, a commercial "sea ranch" was set up in Flinders Bay, Western Australia, to raise abalone. The ranch is based on an artificial reef made up of 5000 () separate concrete units called ''abitats'' (abalone habitats). The 900 kg abitats can host 400 abalone each. The reef is seeded with young abalone from an onshore hatchery. The abalone feed on seaweed that has grown naturally on the habitats, with the ecosystem enrichment of the bay also resulting in growing numbers of dhufish, pink snapper, wrasse, and Samson fish, among other species. Brad Adams, from the company, has emphasised the similarity to wild abalone and the difference from shore-based aquaculture. "We're not aquaculture, we're ranching, because once they're in the water they look after themselves."


Other groups

Other groups include aquatic reptiles, amphibians, and miscellaneous invertebrates, such as echinoderms and jellyfish. They are separately graphed at the top right of this section, since they do not contribute enough volume to show clearly on the main graph. Commercially harvested echinoderms include sea cucumbers and sea urchins. In China, sea cucumbers are farmed in artificial ponds as large as .


Around the world

Global fish production peaked at about 171 million tonnes in 2016, with aquaculture representing 47 percent of the total and 53 percent if non-food uses (including reduction to fishmeal and fish oil) are excluded. With capture fishery production relatively static since the late 1980s, aquaculture has been responsible for the continuing growth in the supply of fish for human consumption. Global aquaculture production (including aquatic plants) in 2016 was 110.2 million tonnes, with the first-sale value estimated at US$243.5 billion. The contribution of aquaculture to the global production of capture fisheries and aquaculture combined has risen continuously, reaching 46.8 percent in 2016, up from 25.7 percent in 2000. With 5.8 percent annual growth rate during the period 2001–2016, aquaculture continues to grow faster than other major food production sectors, but it no longer has the high annual growth rates experienced in the 1980s and 1990s. In 2012, the total world production of fisheries was 158 million tonnes, of which aquaculture contributed 66.6 million tonnes, about 42%. FAO (2014
The State of World Fisheries and Aquaculture 2014 (SOFIA)
/ref> The growth rate of worldwide aquaculture has been sustained and rapid, averaging about 8% per year for over 30 years, while the take from wild fisheries has been essentially flat for the last decade. The aquaculture market reached $86 billion in 2009. Aquaculture is an especially important economic activity in China. Between 1980 and 1997, the Chinese Bureau of Fisheries reports, aquaculture harvests grew at an annual rate of 16.7%, jumping from 1.9 million tonnes to nearly 23 million tonnes. In 2005, China accounted for 70% of world production. Aquaculture is also currently one of the fastest-growing areas of food production in the U.S. About 90% of all U.S. shrimp consumption is farmed and imported. In recent years, salmon aquaculture has become a major export in southern Chile, especially in Puerto Montt, Chile's fastest-growing city. A Food and Agriculture Organization, United Nations report titled ''The State of the World Fisheries and Aquaculture'' released in May 2014 maintained fisheries and aquaculture support the livelihoods of some 60 million people in Asia and Africa. FAO estimates that in 2016, overall, women accounted for nearly 14 percent of all people directly engaged in the fisheries and aquaculture primary sector.


National laws, regulations, and management

Laws governing aquaculture practices vary greatly by country and are often not closely regulated or easily traceable. In the United States, land-based and nearshore aquaculture is regulated at the National Aquaculture Act of 1980, federal and state levels; however, no national laws govern offshore aquaculture in U.S. exclusive economic zone waters. In June 2011, the Department of Commerce and National Oceanic and Atmospheric Administration released national aquaculture policies to address this issue and "to meet the growing demand for healthy seafood, to create jobs in coastal communities, and restore vital ecosystems." In 2011, Congresswoman Lois Capps introduced the ''National Sustainable Offshore Aquaculture Act of 2011'' "to establish a regulatory system and research program for sustainable offshore aquaculture in the United States exclusive economic zone"; however, the bill was not enacted into law.


Over-reporting

China overwhelmingly dominates the world in reported aquaculture output, reporting a total output which is double that of the rest of the world put together. However, there are some historical issues with the accuracy of China's returns. In 2001, the fisheries scientists Reg Watson and Daniel Pauly expressed concerns in a letter to ''Nature'', that China was over reporting its catch from wild fisheries in the 1990s. They said that made it appear that the global catch since 1988 was increasing annually by 300,000 tonnes, whereas it was really shrinking annually by 350,000 tonnes. Watson and Pauly suggested this may be have been related to Chinese policies where state entities that monitored the economy were also tasked with increasing output. Also, until more recently, the promotion of Chinese officials was based on production increases from their own areas. China disputed this claim. The official Xinhua News Agency quoted Yang Jian, director general of the Agriculture Ministry's Bureau of Fisheries, as saying that China's figures were "basically correct". However, the FAO accepted there were issues with the reliability of China's statistical returns, and for a period treated data from China, including the aquaculture data, apart from the rest of the world.


Aquacultural methods


Mariculture

Mariculture Fish cages containing salmon in Sound of Arisaig, Loch Ailort, Scotland. Mariculture is a specialized branch of aquaculture (which includes freshwater aquaculture) involving the cultivation of marine organisms for food and other products in the op ...
refers to the cultivation of marine organisms in seawater, usually in sheltered coastal or offshore waters. The farming of marine fish is an example of mariculture, and so also is the farming of marine crustaceans (such as
shrimp Shrimp are Decapoda, decapod crustaceans with elongated bodies and a primarily swimming mode of locomotion – most commonly Caridea and Dendrobranchiata. More narrow definitions may be restricted to Caridea, to smaller species of either group ...

shrimp
), mollusks (such as
oyster Oyster is the common name Common may refer to: Places * Common, a townland in County Tyrone, Northern Ireland * Boston Common Boston Common (also known as the Common) is a central public park in downtown Boston, Massachusetts. It is someti ...

oyster
s), and seaweed. Channel catfish (''Ictalurus punctatus''), hard clams (''Mercenaria mercenaria'') and Atlantic salmon (''Salmo salar'') are prominent in the U.S. mariculture. Mariculture may consist of raising the organisms on or in artificial enclosures such as in floating netted enclosures for salmon and on racks for oysters. In the case of enclosed salmon, they are fed by the operators; oysters on racks filter feed on naturally available food. Abalone have been farmed on an artificial reef consuming seaweed which grows naturally on the reef units.


Integrated

Integrated multi-trophic aquaculture (IMTA) is a practice in which the byproducts (wastes) from one species are recycled to become inputs (fertilizers, food) for another. Fed aquaculture (for example,
fish Fish are , , -bearing animals that lack with . Included in this definition are the living , s, and and as well as various extinct related groups. Around 99% of living fish species are ray-finned fish, belonging to the class , with over 95 ...

fish
,
shrimp Shrimp are Decapoda, decapod crustaceans with elongated bodies and a primarily swimming mode of locomotion – most commonly Caridea and Dendrobranchiata. More narrow definitions may be restricted to Caridea, to smaller species of either group ...

shrimp
) is combined with inorganic extractive and organic extractive (for example, shellfish) aquaculture to create balanced systems for environmental sustainability (biomitigation), economic stability (product diversification and risk reduction) and social acceptability (better management practices). "Multi-trophic" refers to the incorporation of species from different trophic level, trophic or nutritional levels in the same system.Chopin T. 2006. Integrated multi-trophic aquaculture. What it is, and why you should care ... and don't confuse it with polyculture. Northern Aquaculture, Vol. 12, No. 4, July/August 2006, pg. 4. This is one potential distinction from the age-old practice of aquatic polyculture, which could simply be the co-culture of different fish species from the same trophic level. In this case, these organisms may all share the same biological and chemical processes, with few synergy, synergistic benefits, which could potentially lead to significant shifts in the ecosystem. Some traditional polyculture systems may, in fact, incorporate a greater diversity of species, occupying several Ecological niche, niches, as extensive cultures (low intensity, low management) within the same 2006"/> A working IMTA system can result in greater total production based on mutual benefits to the co-cultured species and improved ecosystem health, even if the production of individual species is lower than in a monoculture over a short-term period. Sometimes the term "integrated aquaculture" is used to describe the integration of monocultures through water transfer. For all intents and purposes, however, the terms "IMTA" and "integrated aquaculture" differ only in their degree of descriptiveness. Aquaponics, fractionated aquaculture, integrated agriculture-aquaculture systems, integrated peri-urban-aquaculture systems, and integrated fisheries-aquaculture systems are other variations of the IMTA concept.


Netting materials

Various materials, including nylon, polyester, polypropylene, polyethylene, plastic-coated welded wire, rubber, patented rope products (Spectra, Thorn-D, Dyneema), galvanized steel and copper are used for netting in aquaculture fish enclosures around the world. All of these materials are selected for a variety of reasons, including design feasibility, material strength, cost, and corrosion resistance. Recently, copper alloys have become important netting materials in aquaculture because they are antimicrobial (i.e., they destroy bacteria, viruses, fungi,
algae Algae (; singular alga ) is an informal term for a large and diverse group of s. It is a grouping that includes species from multiple distinct s. Included organisms range from , such as '','' and the s, to forms, such as the , a large whi ...

algae
, and other microbes) and they therefore prevent biofouling (i.e., the undesirable accumulation, adhesion, and growth of microorganisms, plants, algae, tubeworms, barnacles, mollusks, and other organisms). By inhibiting microbial growth, copper alloy aquaculture cages avoid costly net changes that are necessary with other materials. The resistance of organism growth on copper alloy nets also provides a cleaner and healthier environment for farmed fish to grow and thrive.


Issues

If performed without consideration for potential local environmental impacts, aquaculture in inland waters can result in more environmental damage than wild fisheries of the world, wild fisheries, though with less waste produced per kg on a global scale. Local concerns with aquaculture in inland waters may include waste handling, side-effects of antibiotics, competition between farmed and wild animals, and the potential introduction of invasive species, invasive plant and animal species, or foreign pathogens, particularly if unprocessed fish are used to feed more marketable Carnivore, carnivorous fish. If non-local live feeds are used, aquaculture may introduce exotic plants or animals with disastrous effects. Improvements in methods resulting from advances in research and the availability of commercial feeds has reduced some of these concerns since their greater prevalence in the 1990s and 2000s . Fish waste is organic and composed of nutrients necessary in all components of aquatic food webs. In-ocean aquaculture often produces much higher than normal fish waste concentrations. The waste collects on the ocean bottom, damaging or eliminating bottom-dwelling life. Waste can also decrease dissolved oxygen levels in the water column, putting further pressure on wild animals. An alternative model to food being added to the ecosystem, is the installation of artificial reef structures to increase the habitat niches available, without the need to add any more than ambient feed and nutrient. This has been used in the "ranching" of abalone in Western Australia.


Impacts on wild fish

Some carnivorous and omnivorous farmed fish species are fed wild forage fish. Although carnivorous farmed fish represented only 13 percent of aquaculture production by weight in 2000, they represented 34 percent of aquaculture production by value. Farming of carnivorous species like salmon and shrimp leads to a high demand for forage fish to match the nutrition they get in the wild. Fish do not actually produce omega-3 fatty acids, but instead accumulate them from either consuming microalgae that produce these fatty acids, as is the case with forage fish like herring and sardines, or, as is the case with fatty predatory fish, like salmon, by eating prey fish that have accumulated omega-3 fatty acids from microalgae. To satisfy this requirement, more than 50 percent of the world fish oil production is fed to farmed salmon. Farmed salmon consume more
wild fish A fishery Fishery is the enterprise of raising or harvesting fish and other aquatic life. Commercial fisheries include wild fisheries and Fish farming, fish farms, both in fresh water (about 10% of all catch) and the oceans (about 90%). About 500 ...
than they generate as a final product, although the efficiency of production is improving. To produce one pound of farmed salmon, products from several pounds of wild fish are fed to them - this can be described as the "fish-in-fish-out" (FIFO) ratio. In 1995, salmon had a FIFO ratio of 7.5 (meaning 7.5 pounds of wild fish feed were required to produce 1 pound of salmon); by 2006 the ratio had fallen to 4.9. Additionally, a growing share of fish oil and fishmeal come from residues (byproducts of fish processing), rather than dedicated whole fish. In 2012, 34 percent of fish oil and 28 percent of fishmeal came from residues. However, fishmeal and oil from residues instead of whole fish have a different composition with more ash and less protein, which may limit its potential use for aquaculture. As the salmon farming industry expands, it requires more wild forage fish for feed, at a time when seventy-five percent of the world's monitored fisheries are already near to or have exceeded their maximum sustainable yield.Seafood Choices Alliance (2005
It's all about salmon
The industrial-scale extraction of wild forage fish for salmon farming then impacts the survivability of the wild predator fish who rely on them for food. An important step in reducing the impact of aquaculture on wild fish is shifting carnivorous species to plant-based feeds. Salmon feeds, for example, have gone from containing only fishmeal and oil to containing 40 percent plant protein. The USDA has also experimented with using grain-based feeds for farmed trout. When properly formulated (and often mixed with fishmeal or oil), plant-based feeds can provide proper nutrition and similar growth rates in carnivorous farmed fish. Another impact aquaculture production can have on wild fish is the risk of fish escaping from coastal pens, where they can interbreed with their wild counterparts, diluting wild genetic stocks. Escaped fish can become invasive species, invasive, out-competing native species.


Coastal ecosystems

Aquaculture is becoming a significant threat to Aquatic ecosystem, coastal ecosystems. About 20 percent of mangrove forests have been destroyed since 1980, partly due to
shrimp farm Shrimp farming is an aquaculture Aquaculture (less commonly spelled aquiculture), also known as aquafarming, is the farming of fish, crustaceans, mollusks, aquatic plants, algae, and other organisms. Aquaculture involves cultivating freshwater ...
ing. An extended cost–benefit analysis of the Total Economic Value, total economic value of shrimp aquaculture built on mangrove ecosystems found that the Externality, external costs were much higher than the external benefits. Over four decades, of Indonesian mangroves have been converted to shrimp farms. Most of these farms are abandoned within a decade because of the toxin build-up and nutrient loss.


Pollution from sea cage aquaculture

Aquaculture of salmon, Salmon farms are typically sited in pristine coastal ecosystems which they then pollute. A farm with 200,000 salmon discharges more fecal waste than a city of 60,000 people. This waste is discharged directly into the surrounding aquatic environment, untreated, often containing antibiotics and pesticides." There is also an accumulation of heavy metals on the benthos (seafloor) near the salmon farms, particularly copper and zinc. FAO: Cultured Aquatic Species Information Programme
''Oncorhynchus kisutch'' (Walbaum, 1792)
Rome. Retrieved 8 May 2009.
In 2016, mass fish kill events impacted salmon farmers along Chile's coast and the wider ecology. Increases in aquaculture production and its associated effluent were considered to be possible contributing factors to fish and molluscan mortality. Sea cage aquaculture is responsible for nutrient enrichment of the waters in which they are established. This results from fish wastes and uneaten feed inputs. Elements of most concern are nitrogen and phosphorus which can promote algal growth, including harmful algal blooms which can be toxic to fish. Flushing times, current speeds, distance from the shore and water depth are important considerations when locating sea cages in order to minimize the impacts of nutrient enrichment on coastal ecosystems. The extent of the effects of pollution from sea-cage aquaculture varies depending on where the cages are located, which species are kept, how densely cages are stocked and what the fish are fed. Important species-specific variables include the species' food conversion ratio (FCR) and nitrogen retention.


Freshwater ecosystems

Whole-lake experiments carried out at the Experimental Lakes Area in Ontario, Canada have displayed the potential for cage aquaculture to source numerous changes in freshwater ecosystems. Following the initiation of an experimental rainbow trout cage farm in a small Boreal ecosystem, boreal lake, dramatic reductions in mysis concentrations associated with a decrease in dissolved oxygen were observed. Significant increases in ammonium and total phosphorus, a driver for eutrophication in freshwater systems, were measured in the hypolimnion of the lake. Annual phosphorus inputs from aquaculture waste exceeded that of natural inputs from atmospheric deposition and inflows, and phytoplankton biomass has had a four fold annual increase following the initiation of the experimental farm.


Genetic modification

A type of salmon called the AquAdvantage salmon has been Genetically modified organism, genetically modified for faster growth, although it has not been approved for commercial use, due to controversy. The altered salmon incorporates a growth hormone from a Chinook salmon that allows it to reach full size in 16–28 months, instead of the normal 36 months for Atlantic salmon, and while consuming 25 percent less feed. The U.S. Food and Drug Administration reviewed the AquAdvantage salmon in a draft environmental assessment and determined that it "would not have a significant impact (FONSI) on the U.S. environment."


Fish diseases and parasites

A major difficulty for aquaculture is the tendency towards monoculture and the associated risk of widespread Fish diseases and parasites, disease. Aquaculture is also associated with environmental risks; for instance, Shrimp farm, shrimp farming has caused the destruction of important Mangrove forest, mangrove forests throughout southeast Asia. In the 1990s, disease wiped out China's farmed Farrer's scallop and Chinese white shrimp, white shrimp and required their replacement by other species.


Salinization/acidification of soils

Aquaculture farms are sometimes abandoned after multiple problems (operative, economic, sanitary etc.) develop. The sediment from those former farms can remain hypersaline, Acid, acidic and eroded. Such sediments cannot be used further for aquaculture purposes and can remain unusable for long periods. In addition, the application of Lime (material), lime and other chemicals used in aquaculture to treat the sediment can modify its physicochemical characteristics in undesirable ways, aggravating the problem.


Ecological benefits

While some forms of aquaculture can be devastating to ecosystems, such as shrimp farming in mangroves, other forms can be very beneficial. Shellfish aquaculture adds substantial filter feeding capacity to an environment which can significantly improve water quality. A single oyster can filter 15 gallons of water a day, removing microscopic algal cells. By removing these cells, shellfish are removing nitrogen and other nutrients from the system and either retaining it or releasing it as waste which sinks to the bottom. By harvesting these shellfish the nitrogen they retained is completely removed from the system. Raising and harvesting kelp and other macroalgae directly remove nutrients such as nitrogen and phosphorus. Repackaging these nutrients can relieve eutrophic, or nutrient-rich, conditions known for their low dissolved oxygen which can decimate species diversity and abundance of marine life. Removing algal cells from the water also increases light penetration, allowing plants such as eelgrass to reestablish themselves and further increase oxygen levels.( Aquaculture in an area can provide for crucial ecological functions for the inhabitants. Shellfish beds or cages can provide habitat structure. This structure can be used as shelter by invertebrates, small fish or crustaceans to potentially increase their abundance and maintain biodiversity. Increased shelter raises stocks of prey fish and small crustaceans by increasing recruitment opportunities in turn providing more prey for higher trophic levels. One study estimated that 10 square meters of oyster reef could enhance an ecosystem's biomass by 2.57 kg The shellfish acting as herbivores will also be preyed on. This moves energy directly from primary producers to higher trophic levels potentially skipping out on multiple energetically-costly trophic jumps which would increase biomass in the ecosystem. Seaweed farming is a carbon dioxide removal, carbon negative crop, with a high potential for climate change mitigation . The IPCC Special Report on the Ocean and Cryosphere in a Changing Climate recommends "further research attention" as a mitigation tactic.


Animal welfare

As with the farming of terrestrial animals, social attitudes influence the need for humane practices and regulations in farmed marine animals. Under the guidelines advised by the Farm Animal Welfare Council good animal welfare means both fitness and a sense of well being in the animal's physical and mental state. This can be defined by the Five Freedoms: * Freedom from hunger & thirst * Freedom from discomfort * Freedom from pain, disease, or injury * Freedom to express normal behaviour * Freedom from fear and distress However, the controversial issue in aquaculture is whether fish and farmed marine invertebrates are actually Sentience, sentient, or have the perception and awareness to experience suffering. Although no evidence of this has been found in marine invertebrates, recent studies conclude that fish do have the necessary receptors (nociceptors) to sense noxious stimuli and so are likely to experience states of pain, fear and stress. Consequently, welfare in aquaculture is directed at vertebrates; finfish in particular.


Common welfare concerns

Welfare in aquaculture can be impacted by a number of issues such as stocking densities, behavioural interactions, fish diseases and parasites#Disease, disease and fish diseases and parasites#Parasites, parasitism. A major problem in determining the cause of impaired welfare is that these issues are often all interrelated and influence each other at different times. Optimal stocking density is often defined by the carrying capacity of the stocked environment and the amount of individual space needed by the fish, which is very species specific. Although behavioural interactions such as shoaling and schooling, shoaling may mean that high stocking densities are beneficial to some species, in many cultured species high stocking densities may be of concern. Crowding can constrain normal swimming behaviour, as well as increase aggressive and competitive behaviours such as cannibalism, feed competition, territoriality and dominance/subordination hierarchies. This potentially increases the risk of tissue damage due to abrasion from fish-to-fish contact or fish-to-cage contact. Fish can suffer reductions in food intake and feed conversion ratio, food conversion efficiency. In addition, high stocking densities can result in water flow being insufficient, creating inadequate oxygen supply and waste product removal. Dissolved oxygen is essential for fish respiration and concentrations below critical levels can induce stress and even lead to asphyxiation. Ammonia, a nitrogen excretion product, is highly toxic to fish at accumulated levels, particularly when oxygen concentrations are low. Many of these interactions and effects cause stress in the fish, which can be a major factor in facilitating fish disease. For many parasites, infestation depends on the host's degree of mobility, the density of the host population and vulnerability of the host's defence system. Sea lice are the primary parasitic problem for finfish in aquaculture, high numbers causing widespread skin erosion and haemorrhaging, gill congestion, and increased mucus production. There are also a number of prominent viral and bacterial
pathogen In biology, a pathogen ( el, πάθος, "suffering", "passion" and , "producer of") in the oldest and broadest sense, is any organism that can produce disease. A pathogen may also be referred to as an infectious agent, or simply a Germ theory ...
s that can have severe effects on internal organs and nervous systems.


Improving welfare

The key to improving welfare of marine cultured organisms is to reduce stress to a minimum, as prolonged or repeated stress can cause a range of adverse effects. Attempts to minimise stress can occur throughout the culture process. During grow-out it is important to keep stocking densities at appropriate levels specific to each species, as well as separating size classes and grading to reduce aggressive behavioural interactions. Keeping nets and cages clean can assist positive water flow to reduce the risk of water degradation. Not surprisingly disease and parasitism can have a major effect on fish welfare and it is important for farmers not only to manage infected stock but also to apply disease prevention measures. However, prevention methods, such as vaccination, can also induce stress because of the extra handling and injection. Other methods include adding antibiotics to feed, adding chemicals into water for treatment baths and biological control, such as using cleaner fish, cleaner wrasse to remove lice from farmed salmon. Many steps are involved in transport, including capture, food deprivation to reduce faecal contamination of transport water, transfer to transport vehicle via nets or pumps, plus transport and transfer to the delivery location. During transport water needs to be maintained to a high quality, with regulated temperature, sufficient oxygen and minimal waste products. In some cases anaesthetics may be used in small doses to calm fish before transport. Aquaculture is sometimes part of an environmental rehabilitation program or as an aid in conserving endangered species.


Prospects

Global
wild fisheries A wild fishery is a natural Nature, in the broadest sense, is the natural, physical, material world or universe The universe ( la, universus) is all of space and time and their contents, including planets, stars, galaxies, and al ...
are in decline, with valuable habitat such as estuary, estuaries in critical condition. The aquaculture or fish farm, farming of
piscivorous (''Nerodia sipedon'') eating a fish A piscivore is a carnivore, carnivorous animal that eats primarily fish Fish are Aquatic animal, aquatic, craniate, gill-bearing animals that lack Limb (anatomy), limbs with Digit (anatomy), digits. Th ...
fish, like
salmon Salmon is the common name for several species of ray-finned fish Actinopterygii ( New Latin ('having rays') + Greek ( 'wing, fins')), members of which are known as ray-finned fishes, is a clade A clade (; from grc, , ''klados'', ...

salmon
, does not help the problem because they need to eat products from other fish, such as fish meal and fish oil. Studies have shown that Aquaculture of salmon, salmon farming has major Salmon farming issues, negative impacts on wild salmon, as well as the forage fish that need to be caught to feed them. Knapp G, Roheim CA and Anderson JL (2007
''The Great Salmon Run: Competition Between Wild And Farmed Salmon''
World Wildlife Fund.
Fish that are higher on the trophic level, food chain are less efficient sources of food energy. Apart from fish and shrimp, some aquaculture undertakings, such as seaweed and filter-feeding bivalve mollusks like
oyster Oyster is the common name Common may refer to: Places * Common, a townland in County Tyrone, Northern Ireland * Boston Common Boston Common (also known as the Common) is a central public park in downtown Boston, Massachusetts. It is someti ...

oyster
s, clams, mussels and scallops, are relatively benign and even environmentally restorative. Filter-feeders filter pollutants as well as nutrients from the water, improving water quality. Seaweeds extract nutrients such as inorganic nitrogen and phosphorus directly from the water, and filter-feeding
mollusk Mollusca is the second-largest phylum In biology, a phylum (; plural The plural (sometimes list of glossing abbreviations, abbreviated ), in many languages, is one of the values of the grammatical number, grammatical category of number ...
s can extract nutrients as they feed on particulates, such as
phytoplankton Phytoplankton () are the autotrophic An autotroph or primary producer is an organism that produces complex organic compound , CH4; is among the simplest organic compounds. In chemistry, organic compounds are generally any chemical compoun ...

phytoplankton
and detritus. Some profitable aquaculture cooperatives promote sustainable practices. New methods lessen the risk of biological and chemical pollution through minimizing fish stress, fallowing netpens, and applying Integrated Pest Management. Vaccines are being used more and more to reduce antibiotic use for disease control. Onshore recirculating aquaculture systems, facilities using polyculture techniques, and properly sited facilities (for example, offshore areas with strong currents) are examples of ways to manage negative environmental effects. Recirculating aquaculture systems (RAS) recycle water by circulating it through filters to remove fish waste and food and then recirculating it back into the tanks. This saves water and the waste gathered can be used in compost or, in some cases, could even be treated and used on land. While RAS was developed with freshwater fish in mind, scientists associated with the Agricultural Research Service have found a way to rear saltwater fish using RAS in low-salinity waters. Although saltwater fish are raised in off-shore cages or caught with nets in water that typically has a salinity of 35 parts per thousand (ppt), scientists were able to produce healthy pompano, a saltwater fish, in tanks with a salinity of only 5 ppt. Commercializing low-salinity RAS are predicted to have positive environmental and economical effects. Unwanted nutrients from the fish food would not be added to the ocean and the risk of transmitting diseases between wild and farm-raised fish would greatly be reduced. The price of expensive saltwater fish, such as the pompano and combia used in the experiments, would be reduced. However, before any of this can be done researchers must study every aspect of the fish's lifecycle, including the amount of ammonia and nitrate the fish will tolerate in the water, what to feed the fish during each stage of its lifecycle, the stocking rate that will produce the healthiest fish, etc. Some 16 countries now use geothermal energy for aquaculture, including China, Israel, and the United States."Stabilizing Climate"
in Lester R. Brown, ''Plan B 2.0 Rescuing a Planet Under Stress and a Civilization in Trouble'' (NY: W.W. Norton & Co., 2006), p. 199.
In California, for example, 15 fish farms produce tilapia, bass, and catfish with warm water from underground. This warmer water enables fish to grow all year round and mature more quickly. Collectively these California farms produce 4.5 million kilograms of fish each year.


See also

* Agroecology * Alligator farm * Aquaponics * Blue revolution * Copper alloys in aquaculture * Maggot farming, Maggots used as food for fish * Fish hatchery * Fisheries science * Industrial agriculture (animals)#Aquaculture, Industrial aquaculture * List of commercially important fish species * Recirculating aquaculture system * Resource decoupling Aquaculture by Country: * Aquaculture in Australia * Aquaculture in Canada * Aquaculture in Chile * Aquaculture in China * Aquaculture in East Timor * Aquaculture in the Federated States of Micronesia * Aquaculture in Fiji * Aquaculture in Indonesia * Aquaculture in Kiribati * Aquaculture in Madagascar * Aquaculture in the Marshall Islands * Aquaculture in Nauru * Aquaculture in New Zealand * Aquaculture in Palau * Aquaculture in Papua New Guinea * Aquaculture in Samoa * Aquaculture in the Solomon Islands * Aquaculture in South Africa * Aquaculture in South Korea * Aquaculture in Tonga * Aquaculture in Tuvalu * Aquaculture in Vanuatu


Sources


Notes


References

* *
podcast
* * GESAMP (2008

FAO Reports and Studies No 76. * Hepburn, J. 2002. ''Taking Aquaculture Seriously''. Organic Farming, Winter 2002 © Soil Association. * *
The Scottish Association for Marine Science and Napier University. 2002. Review and synthesis of the environmental impacts of aquaculture
* Higginbotham James ''Piscinae: Artificial Fishponds in Roman Italy'' University of North Carolina Press (June 1997) * Wyban, Carol Araki (1992) ''Tide and Current: Fishponds of Hawai'I'' University of Hawaii Press:: * Timmons, M.B., Ebeling, J.M., Wheaton, F.W., Summerfelt, S.T., Vinci, B.J., 2002. Recirculating Aquaculture Systems: 2nd edition. Cayuga Aqua Ventures. * *


Further reading

* * ''AquaLingua''
''Rice–Fish Culture in China''
(1995), , * * * * *


External links


Aquaculture topic page from Woods Hole Oceanographic Institution
* * *
The Coastal Resources Center

NOAA aquaculture

The University of Hawaii's AquacultureHub

TED-Ed lesson on aquaculture
{{Authority control Aquaculture, Domesticated animals Buildings and structures used to confine animals Sustainable food system