Aquaculture From Wikipedia, the free encyclopedia Aquaculture Aquaculture installations in southern Chile Global harvest of aquatic organisms in million tonnes, 1950–2010, as reported by the FAO [1] Aquaculture, also known as aquafarming, is the farming of aquatic organisms such as fish, crustaceans, molluscs and aquatic plants.[2][3] Aquaculture involves cultivating freshwater and saltwater populations under controlled conditions, and can be contrasted with commercial fishing, which is the harvesting of wild fish.[4] Broadly speaking, finfish and shellfish fisheries can be conceptualized as akin to hunting and gathering while aquaculture is akin to agriculture.[5] Mariculture refers to aquaculture practiced in marine environments and in underwater habitats. According to the 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.[6] The reported output from global aquaculture operations would supply one half of the fish and shellfish that is directly consumed by humans;[7] however, there are issues about the reliability of the reported figures.[8] Further, in current aquaculture practice, products from several pounds of wild fish are used to produce one pound of a piscivorous fish like salmon.[9] Particular kinds of aquaculture include fish farming, shrimp farming, oyster farming, mariculture, algaculture (such as seaweed farming), and the cultivation of ornamental fish. Particular methods include aquaponics and integrated multi-trophic aquaculture, both of which integrate fish farming and plant farming. Contents 1 History 2 21st-century practice 3 Species groups 3.1 Aquatic plants 3.2 Fish 3.3 Crustaceans 3.4 Molluscs 3.5 Other groups 4 Around the world 5 Over reporting 6 Methods 6.1 Mariculture 6.2 Integrated 7 Netting materials 8 Issues 8.1 Fish oils 8.2 Impacts on wild fish 8.3 Coastal ecosystems 8.4 Genetic modification 9 Animal welfare 9.1 Common welfare concerns 9.2 Improving welfare 10 Prospects 11 See also 12 Notes 13 References 14 Further reading 15 External links History Photo of dripping, cup-shaped net, approximately 6 feet (1.8 m) in diameter and equally tall, half full of fish, suspended from crane boom, with 4 workers on and around larger, ring-shaped structure in water Workers harvest catfish from the Delta Pride Catfish farms in Mississippi The indigenous Gunditjmara people in Victoria, Australia may have raised eels as early as 6000 BC. There is evidence that they developed about 100 square kilometres (39 sq mi) of volcanic floodplains in the vicinity of Lake Condah into a complex of channels and dams, that they used woven traps to capture eels, and preserve eels to eat all year round.[10][11] Aquaculture was operating in China circa 2500 BC.[12] When the waters subsided after river floods, some fishes, mainly carp, were trapped in lakes. Early aquaculturists fed their brood using nymphs and silkworm feces, and ate them. A fortunate genetic mutation of carp led to the emergence of goldfish during the Tang Dynasty. Japanese cultivated seaweed by providing bamboo poles and, later, nets and oyster shells to serve as anchoring surfaces for spores. Romans bred fish in ponds.[13] In central Europe, early Christian monasteries adopted Roman aquacultural practices.[14] Aquaculture spread in Europe during the Middle Ages since away from the seacoasts and the big rivers fish had to be salted in order to not perish.[15] Improvements in transportation during the 19th century made fresh fish easily available and inexpensive, even in inland areas, making aquaculture less popular. Hawaiians constructed oceanic fish ponds (see Hawaiian aquaculture). A remarkable example is a fish pond dating from at least 1,000 years ago, at Alekoko. Legend says that it was constructed by the mythical Menehune dwarf people. In 1859 Stephen Ainsworth of West Bloomfield, New York, began experiments with brook trout. By 1864 Seth Green had established a commercial fish hatching operation at Caledonia Springs, near Rochester, New York. By 1866, with the involvement of Dr. W. W. Fletcher of Concord, Massachusetts, artificial fish hatcheries were under way in both Canada and the United States.[16] When the Dildo Island fish hatchery opened in Newfoundland in 1889, it was the largest and most advanced in the world. Californians harvested wild kelp and attempted to manage supply circa 1900, later labeling it a wartime resource.[17] 21st-century practice About 430 (97%) of the species cultured as of 2007 were domesticated during the 20th century, of which an estimated 106 came in the decade to 2007. Given the long-term importance of agriculture, it is interesting to note that 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.[18] 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,[19] through diseases such as smallpox and diphtheria, that like most infectious diseases, move to humans from animals. No human pathogens of comparable virulence have yet emerged from marine species. Harvest stagnation in wild fisheries and overexploitation of popular marine species, combined with a growing demand for high quality protein, encourage aquaculturists to domesticate other marine species.[20][21] Species groups Global aquaculture production in million tonnes, 1950–2010, as reported by the FAO [1] Main species groups Minor species groups Aquatic plants See also: Algaculture and Seaweed farming Microalgae, also referred to as phytoplankton, microphytes, or planktonic algae constitute the majority of cultivated algae. Macroalgae, commonly known as 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. Fish Main article: Fish farming The farming of fish is the most common form of aquaculture. It involves raising fish commercially in tanks, ponds, 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. Worldwide, the most important fish species used in fish farming are, in order, carp, salmon, tilapia and catfish.[1] In the Mediterranean, young bluefin tuna are netted at sea and towed slowly towards the shore. They are then interned in offshore pens where they are further grown for the market.[22] In 2009, researchers in Australia managed for the first time to coax tuna (Southern bluefin) to breed in landlocked tanks. Crustaceans See also: Shrimp farm and Freshwater prawn farm Commercial shrimp farming began in the 1970s, and production grew steeply thereafter. Global production reached more than 1.6 million tonnes in 2003, worth about 9 billion U.S. dollars. 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 broodstock is shipped worldwide. Virtually all farmed shrimp are penaeids (i.e., shrimp of the family Penaeidae), and just two species of shrimp, the Pacific white shrimp and the giant tiger prawn, 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 ecological problems, repeated disease outbreaks, and pressure and criticism from both NGOs 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 farming practices through the Seafood Watch program.[23] Freshwater prawn farming shares many characteristics with, including many problems with, marine shrimp farming. Unique problems are introduced by the developmental life cycle of the main species, the giant river prawn.[24] The global annual production of freshwater prawns (excluding crayfish and crabs) in 2003 was about 280,000 tonnes of which China produced 180,000 tonnes followed by India and Thailand with 35,000 tonnes each. Additionally, China produced about 370,000 tonnes of Chinese river crab.[25] Molluscs Abalone farm See also: Oyster farming and Geoduck aquaculture Aquacultured shellfish include various 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.[26] 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. Abalone farming began in the late 1950s and early 1960s in Japan and China.[27] Since the mid-1990s, this industry has become increasingly successful.[28] Over-fishing 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 (ASC) with the Dutch Sustainable Trade Initiative (IDH) to manage the global standards and certification programs.[29] 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 1,000 acres (400 ha).[30]
Posted on: Mon, 17 Nov 2014 12:13:43 +0000
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