Aquaculture
Aquaculture (sometimes misspelled "aquiculture") 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.
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.
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 occurance 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 rigourous 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 acreas 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
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.
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