Aquaculture
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Aquaculture is the cultivation of aquatic organisms, such as fish, shellfish, algae and other aquatic plants. Mariculture is specifically marine aquaculture, and thus is a subset of aquaculture. Some examples of aquaculture include raising catfish and tilapia in freshwater ponds, growing cultured pearls, and farming salmon in net-pens set out in a bay. Fish farming is a common kind of aquaculture.
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Benefits
Aquaculture has been one of the fastest growing segments of global food production in recent decades, and has been hailed as an answer to declining wild fish stocks caused largely by overfishing.
Tuna farming in Australia, as well as of other species, has had immense success.
Salmon farming in the Tenth Region of Chile has, for the first time, brought a stable industry to many depressed backwater towns and started a cash flow; previously, the only employment options had been leaving home, relying on the government, or subsistence farming.
In an unusual arrangement in Hawaii in the United States, aquaculture is carried out with various combinations of Deep Ocean Water (DOW), and Surface Ocean Water (SOW) which is drawn to the surface by the Natural Energy Laboratory of Hawaii as part of research into OTEC renewable energy. This allows fish which require clean cold water to be raised on shore in water drawn from the ocean depths.
Challenges
In countries like the U.K., Canada, Norway, and Chile, salmon and trout farming are one of the fastest-growing forms of agriculture. Salmon farming, like other food producing operations such as beef, wheat or tomatoes can impact the environment. In particular organic wastes from fish cages can have a significant effect on water quality and the population structure of organisms, increasing the occurrence of toxic algal blooms, as has been the case in Scotland, but even a month of fallow time can return the area to pristine condition.
Like other agriculture production, it must stand up to a rigorous evaluation of any environmental impact. Salmon aquaculture has come under increasing scrutiny from environmental nongovernmental organizations (ENGO's). In Canada, salmon farming sites occupy a small portion of the coastal zone areas where they are located. The total area occupied by Canadian salmon farms in British Columbia and the Bay of Fundy in New Brunswick is about 8,900 acres (36 km²) which is less than 0.01% of the coastal area where these sites are located.
Wild Pacific and Atlantic salmon stocks have seen significant declines over the last several decades, before salmon farming operations started. These declines were caused by a combination of factors including climate change, overfishing and freshwater habitat destruction. Canadian salmon farmers have significantly reduced the escape of their salmon. The evidence shows that the escape of farmed salmon on Canada's west coast poses low risk to Pacific salmon, however concerns have been raised on the East coast that wild Atlantic salmon may interbreed with salmon that escape from farms.
Many farmed fish species are carnivorous, meaning that other wild fish species must be harvested to maintain the fish farm, but these are species which are not used for human consumption. A large portion of the fish meal used in fish feeds comes from the trimmings and discards of commercial species. More and more feeds are made using poultry and vegetable oils as substitutes for fish oil.
Other problems with aquaculture include the potential for increasing the spread of unwanted invasive species, as farmed species are often not native to the area in which they are farmed. When these species escape, they can compete with native species and damage ecosystems. Another problem is the spread of introduced parasites, pests, and diseases.
See also: fishery
References
- Hepburn, J. 2002. Taking Aquaculture Seriously. Organic Farming, Winter 2002 © Soil Association.
- Naylor, R.L., S.L. Williams, and D.R. Strong. 2001. Aquaculture – A Gateway For Exotic Species. Science, 294: 1655-6.
- The Scottish Association for Marine Science and Napier University. 2002. Review and synthesis of the environmental impacts of aquaculture (http://www.scotland.gov.uk/cru/kd01/green/reia-01.asp)
External links
- Organic Aquaculture: (http://www.certifiedorganic.bc.ca/rcbtoa/services/aquaculture.html) Articles and references on the merits and otherwise of farming fish organically.
- Aquaculture Knowledge Environment: (http://govdocs.aquake.org) A searchable online library of government and United Nations documents covering nearly every aspect of aquaculture from pond construction to international codes of conduct.
- World Aquaculture Society: (http://www.was.org/main/Default.asp) Founded in 1970, the primary focus of WAS is to improve communication and information exchange within the diverse global aquaculture community.
- Natural Energy Laboratory of Hawaii Authority (http://www.nelha.org/) Learn how NELHA and its tenants are using sunshine, seawater and ingenuity to bring economic development and diversity.
- Friends of NELHA (http://www.keaholepoint.org/)Friends of NELHA [FON] is a nonprofit corporation formed for education and outreach tours related to research, commercial and pre-commercial activities at Keahole Point, north of Kailua Kona, Hawaii.
- Watershed Watch Society (http://www.watershed-watch.org/ww/Sealicefacts/sealicefacts_main.htm) Salmon farming and sea licecs:Akvakultura