Aquaculture

From Wikipedia, the free encyclopedia

Jump to: navigation, search
Aquaculture installations in southern Chile.

Aquaculture is the farming of freshwater and saltwater organisms including fish, molluscs, crustaceans and aquatic plants. Unlike fishing, aquaculture, also known as aquafarming, implies the cultivation of aquatic populations under controlled conditions.[1] Mariculture refers to aquaculture practiced in marine environments. Particular kinds of aquaculture include algaculture (the production of kelp/seaweed and other algae), fish farming, shrimp farming, oyster farming, and the growing of cultured pearls. Particular methods include aquaponics, which integrates fish farming and plant farming.

Contents

[edit] History

Workers harvest catfish from the Delta Pride Catfish farms in Mississippi

Aquaculture began in China circa 2500 BC[citation needed]. When the waters subsided after river floods, some fishes, mainly carp, were trapped in lakes. Nascent aquaculturists fed their brood using nymphs and silkworm feces, and ate the fish for their protein. A fortunate genetic mutation of carp led to the emergence of goldfish during the Tang Dynasty.

Hawaiians practiced aquaculture by constructing 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. The Japanese cultivated seaweed by providing bamboo poles and, later, nets and oyster shells to serve as anchoring surfaces for spores. The Romans bred fish in ponds.

In central Europe, early Christian monasteries adopted Roman aquacultural practices.[2] Aquaculture spread in Europe during the Middle Ages, since away from the seacoasts and the big rivers, fish were scarce/expensive. Improvements in transportation during the 19th century made fish easily available and inexpensive, even in inland areas, making aquaculture less popular.

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, NY. By 1866, with the involvement of Dr. W. W. Fletcher of Concord Mass, artificial fish hatching operations were under way in both Canada and the United States.[3] When the Dildo Island fish hatchery opened in Newfoundland Canada in 1889, it was the largest and most advanced in the world.

California residents harvested wild kelp and attempted to manage supply starting circa 1900, later labeling it a wartime resource.[4]

Tilapia, a commonly farmed fish due to its adaptability

About 430 (97%) of the aquatic species cultured as of 2007 were domesticated during the 20th century, of which an estimated 106 aquatic species 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. Domesticating an aquatic species typically involves about a decade of scientific research. [5] Aquatic species involve fewer risks than that of land animals, which took a large toll in human lives through diseases such as smallpox and bird and swine flu, that like most infectious diseases, are transferred to humans from animals. No human pathogens of comparable virulence have yet emerged from marine species.

The stagnation in the world's fisheries and overexploitation of the most popular marine fish species, combined with the world's rapidly growing demand for this high quality protein provide additional impetus to domesticate marine species.

[edit] World production

In 2004, the total world production of fisheries was 140.5 million tonnes of which aquaculture contributed 45.5 million tonnes or about 32% of the total world production.[6] The growth rate of worldwide aquaculture has been sustained and rapid, averaging about 8 percent per annum for over thirty years, while the take from wild fisheries has been essentially flat for the last decade.

[edit] Production by country

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 percent, jumping from 1.9 million to nearly 23 million tons. In 2005 China accounted for 70% of the world's aquaculture production.[7][8]

Approximately 90% of all U.S. shrimp consumption is farmed and imported.[9] In recent years salmon aquaculture has become a major export in southern Chile, especially in Puerto Montt and Quellón, Chile's fastest-growing city.

[edit] Environmental impact

As aquaculture has grown, so have concerns about its environmental impact. In fact, aquaculture can be more environmentally damaging than exploiting wild fisheries.[10] These concerns include waste handling, side-effects of antibiotics, competition between farmed and wild varieties, and providing feed for consumer-desired carnivorous fish. However considerable research and commercial feed improvements during the 1990s & 2000s has lessened many of these environmental impacts[11]

Fish waste is organic and composed of nutrients necessary in all components of aquatic food webs. The concentrated nature of aquaculture often leads to higher than normal levels of fish waste in the water. Waste from nearshore, high-intensity operations can adversely affect the environment by decreasing dissolved oxygen levels in the water column.

Species such as salmon are grown in net-contained environments. Unused feed and waste products can contaminate the surrounding sea floor and fish can escape, where they can outcompete wild fish. Escapees can also dilute wild genetic stocks through interbreeding. [12]

Onshore recirculating aquaculture systems, facilities using polyculture techniques, and properly-sited facilities (e.g. offshore or areas with strong currents) are examples of ways to manage the negative environmental effects of fish waste.

Farming carnivorous fish like salmon actually increases the pressure on wild fish, as producing one kilo of farmed salmon requires up to six kilo of wild fish.[13]

Other forms of aquaculture such as the culture of seaweeds and filter feeding bivalve mollusks such as oysters, clams, mussels and scallops are relatively benign environmentally. Seaweeds act to extract nutrients such as inorganic nitrogen and phosphorus directly from the water,[14] and filter feeding molluscan shellfish can extract organic nutrients as they feed on particulates phytoplankton and detritus.[15]

Despite the environmental concerns, profitable aquaculture can funnel money into promoting sustainable practices.[16] New methods minimize the risk of biological and chemical pollution through minimizing stress to fish, fallowing netpens, and applying Integrated Pest Management. Vaccines are being used more and more to reduce antibiotic use for disease control in aquaculture.[17]

[edit] Types of aquaculture

[edit] Algaculture

Main article: Algaculture
An open pond Spirulina farm

Algaculture is a form of aquaculture involving the farming of species of algae. Microalgae, also referred to as phytoplankton, microphytes, or planktonic algae constitue 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.

[edit] Fish farming

Main article: Fish farming

Fish farming is the most common form of aquaculture. It involves raising fish commercially in tanks or 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. Fish species raised by fish farms include salmon, catfish, tilapia, cod, carp and trout.

[edit] Freshwater prawn farming

Main article: Freshwater prawn farm

Freshwater prawn farming shares many characteristics with, and many of the same problems as, marine shrimp farming. Unique problems are introduced by the developmental life cycle of the main species (the giant river prawn, Macrobrachium rosenbergii).[18]

The global annual production of freshwater prawns (excluding crayfish and crabs) in 2003 was about 280,000 tons, of which China produced 180,000 tons, followed by India and Thailand with 35,000 tons each. Additionally, China produced about 370,000 tons of Chinese river crab (Eriocheir sinensis).[19]

[edit] Integrated multi-trophic aquaculture

Main article: Integrated Multi-trophic Aquaculture

Integrated Multi-Trophic Aquaculture (IMTA) is a practice in which the by-products (wastes) from one species are recycled to become inputs (fertilizers, food) for another. Fed aquaculture (e.g. fish, shrimp) is combined with inorganic extractive (e.g. seaweed) and organic extractive (e.g. shellfish) aquaculture to create balanced systems for environmental sustainability (biomitigation), economic stability (product diversification and risk reduction) and social acceptability (better management practices).[14]

"Multi-Trophic" refers to the incorporation of species from different trophic or nutritional levels in the same system.[20] 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 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 niches, as extensive cultures (low intensity, low management) within the same pond. The "Integrated" in IMTA refers to the more intensive cultivation of the different species in proximity of each other, connected by nutrient and energy transfer through water.

Ideally, the biological and chemical processes in an IMTA system should balance. This is achieved through the appropriate selection and proportions of different species providing different ecosystem functions. The co-cultured species are typically more than just biofilters; they are harvestable crops of commercial value.[20] 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.[21]

Sometimes the term "Integrated Aquaculture" is used to describe the integration of monocultures through water transfer.[21] For all intents and purposes however, the terms "IMTA" and "integrated aquaculture" differ only in their degree of descriptiveness.Aquaponics, fractionated aquaculture, IAAS (integrated agriculture-aquaculture systems), IPUAS (integrated peri-urban-aquaculture systems), and IFAS (integrated fisheries-aquaculture systems) are other variations of the IMTA concept.

[edit] Mariculture

Main article: Mariculture

Mariculture is a specialized branch of aquaculture involving the cultivation of marine organisms 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, prawns, or oysters in saltwater ponds. Non-food products produced by mariculture include: fish meal, nutrient agar, jewelry (e.g. cultured pearls) and cosmetics.

[edit] Shrimp farming

Main article: Shrimp farm

A shrimp farm is an aquaculture business for the cultivation of marine shrimp for human consumption. Commercial shrimp farming began in the 1970s, and production grew steeply thereafter. Global production reached more than 1.6 million tonnes in 2003, representing a value of nearly 9,000 million 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 Penaeus vannamei (Pacific white shrimp) and the Penaeus monodon (giant tiger prawn) account for roughly 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 regulation by governments. In 1999, governments, industry representatives, and environmental organizations initiated a program aimed at developing and promoting more sustainable farming practices.

[edit] Types of fish in aquaculture

Mirgala, Rohita, Lates calcrifer (sea bass), Murrels

[edit] See also

[edit] Notes

  1. ^ American Heritage Definition of Aquaculture
  2. ^ Jhingran, V.G., Introduction to aquaculture. 1987, United Nations Development Programme, Food and Agriculture Organization of the United Nations, Nigerian Institute for Oceanography and Marine Research.
  3. ^ Milner, James W. (1874). "The Progress of Fish-culture in the United States". United States Commission of Fish and Fisheries Report of the Commissioner for 1872 and 1873. 535 – 544 (http://penbay.org/cof/cof_1872_1873.html)
  4. ^ Peter Neushul, Seaweed for War: California's World War I kelp industry, Technology and Culture 30 (July 1989), 561-583.
  5. ^ http://www.sciencemag.org/cgi/content/full/sci;316/5823/382
  6. ^ a b c d e FAO (2006) The State of World Fisheries and Aquaculture (SOPHIA)
  7. ^ Wired 12.05: The Bluewater Revolution
  8. ^ washingtonpost.com: Fish Farming's Bounty Isn't Without Barbs
  9. ^ The State of World Fisheries and Aquaculture (SOFIA) 2004
  10. ^ Diamond, Jared. Collapse: How societies choose to fail or succeed. Viking Press, 2005. pgs. 479-485
  11. ^ Costa-Pierce, B.A., Author/Editor. 2002. Ecological Aquaculture. Blackwell Science, Oxford, UK.
  12. ^ David Suzuki Foundation: Open-net-cage fish farming
  13. ^ Swiss WWF Factsheet, Page 7, Heading "Fische und Meeresfrüchte aus Zuchten"
  14. ^ a b Chopin T, Buschmann AH, Halling C, Troell M, Kautsky N, Neori A, Kraemer GP, Zertuche-Gonzalez JA, Yarish C and Neefus C. 2001. Integrating seaweeds into marine aquaculture systems: a key toward sustainability. Journal of Phycology 37: 975-986.
  15. ^ "Rice, M.A. 2008. Environmental impacts of shellfish aquaculture". http://www.nrac.umd.edu/files/Factsheets/105-Environmental%20effects.pdf. 
  16. ^ "Aquaculture: Issues and Opportunities for Sustainable Production and Trade, published by ITCSD in July 2006"
  17. ^ "Pew Oceans Commission report on Aquaculture"
  18. ^ New, M. B.: Farming Freshwater Prawns; FAO Fisheries Technical Paper 428, 2002. ISSN 0429-9345.
  19. ^ Data extracted from the FAO Fisheries Global Aquaculture Production Database for freshwater crustaceans. The most recent data sets are for 2003 and sometimes contain estimates. Accessed June 28, 2005.
  20. ^ a b 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.
  21. ^ a b Neori A, Chopin T, Troell M, Buschmann AH, Kraemer GP, Halling C, Shpigel M and Yarish C. 2004. Integrated aquaculture: rationale, evolution and state of the art emphasizing seaweed biofiltration in modern mariculture. Aquaculture 231: 361-391.

[edit] References

[edit] Further reading

[edit] External links

 This article's external links may not follow Wikipedia's content policies or guidelines. Please improve this article by removing excessive or inappropriate external links. (June 2009)
Search Wiktionary Look up aquaculture in Wiktionary, the free dictionary.
Search Wikimedia Commons Wikimedia Commons has media related to: Aquaculture
Global
Regional
Topic Specific
Web Resources
v • d • e
Aquaculture and fish farming articles
Aquaculture
Fish farming
Diseases etc
v • d • e
Fisheries and fishing topic areas
Fisheries
Fishing
Industry
Recreational
Techniques
Tackle
Locations
List of articles by topic areas · Alphabetical list of articles · Fisheries glossary
Retrieved from "http://en.wikipedia.org/wiki/Aquaculture"
Personal tools