Editing Fish farming (section)

=== Cage system ===
[[File:Giant.gourami.arp.jpg|thumb|right|[[Giant gourami]] is often raised in cages in central Thailand.]]

Fish cages are placed in lakes, bayous, ponds, rivers, or oceans to contain and protect fish until they can be harvested.<ref name="scielo.br"/> The method is also called "off-shore cultivation"<ref>{{cite web|url=http://www.sourcewatch.org/index.php?title=Offshore_fish_farming_legislation|title=Offshore fish farming legislation|access-date=30 January 2016|url-status=dead|archive-url=https://web.archive.org/web/20160204173237/http://www.sourcewatch.org/index.php?title=Offshore_fish_farming_legislation|archive-date=4 February 2016}}</ref> when the cages are placed in the sea. They can be constructed of a wide variety of components. Fish are stocked in cages, artificially fed, and harvested when they reach market size. A few advantages of fish farming with cages are that many types of waters can be used (rivers, lakes, filled quarries, etc.), many types of fish can be raised, and fish farming can co-exist with sport fishing and other water uses.<ref name="scielo.br"/>

[[File:Sustainable fish farming 010.jpg|thumb|left|Fish cages in [[Lake Victoria]], [[Uganda]]]]
Cage farming of fishes in open seas is also gaining in popularity. Given concerns of disease, poaching, poor water quality, etc., generally pond systems are considered simpler to start and easier to manage. Also, the past occurrences of cage-failures leading to escapes, have raised concern regarding the culture of non-native fish species in dam or open-water cages. On August 22, 2017, there was a massive failure of such cages at a commercial fishery in Washington state in [[Puget Sound]], leading to release of nearly 300,000 Atlantic salmon in non-native waters. This is believed to risk endangering the native Pacific salmon species.<ref>{{Cite web |date=2017-08-22 |title=Please go fishing, Washington state says after farmed Atlantic salmon escape broken net |url=https://www.seattletimes.com/seattle-news/environment/oops-after-accidental-release-of-atlantic-salmon-fisherman-being-told-catch-as-many-as-you-want/ |access-date=2022-08-02 |website=The Seattle Times |language=en-US}}</ref>

Marine Scotland has kept records of caged fish escapes since 1999. They have recorded 357 fish escape incidents with 3,795,206 fish escaping into fresh and salt water. One company, Dawnfresh Farming Limited, has been responsible for 40 incidents and the escape of 152,790 rainbow trout into freshwater lochs.<ref>{{Cite web |title=Scotland's Aquaculture {{!}} Fish Escapes |url=http://aquaculture.scotland.gov.uk/data/fish_escapes.aspx |access-date=2021-12-21 |website=aquaculture.scotland.gov.uk}}</ref>

[[File:2019-03-16 01 Aquaculture in Chile.jpg|thumb|Fish cages in [[Castro, Chile]]]]
Though the cage-industry has made numerous technological advances in cage construction in recent years, the risk of damage and escape due to storms is always a concern.<ref name="scielo.br">{{cite journal|title=Growing, losing or introducing? Cage aquaculture as a vector for the introduction of non-native fish in Furnas Reservoir, Minas Gerais, Brazil|first1=Valter Monteiro de|last1=Azevedo-Santos|first2=Odila|last2=Rigolin-Sá|first3=Fernando Mayer|last3=Pelicice|volume=9|issue=4|pages=915–919|doi=10.1590/S1679-62252011000400024|journal=Neotropical Ichthyology|year=2011|doi-access=free}}</ref>

[[Semi-submersible]] marine technology is beginning to impact fish farming. In 2018, 1.5 million [[salmon]] are in the middle of a year-long trial at Ocean Farm 1 off the coast of [[Norway]]. The semi-submersible {{USD|300 million}} project is the world's first deep-sea aquaculture project, and includes {{convert|200|ft|m|adj=on|order=flip|sp=us}}-high by {{convert|300|ft|m|adj=on|order=flip|sp=us}}-diameter pen made from a series of mesh-wire frames and nets. It is designed to disperse wastes better than more conventional farms in sheltered coastal waters, therefore supporting higher fish packing density.<ref>{{Cite news |date=2018-07-30 |title=The $300 Million Plan to Farm Salmon in the Middle of the Ocean |language=en |work=Bloomberg.com |url=https://www.bloomberg.com/news/articles/2018-07-30/this-300-million-deepwater-platform-houses-1-5-million-salmon |access-date=31 July 2018}}</ref>

In [[Maritime Southeast Asia]], traditional fish cages built around an offshore wooden platform are generally called [[kelong]]. They are usually used to temporarily keep caught fish until sold or cooked, but some are used for fish farming.<ref>{{Cite web |date=2014-12-18 |title=Death of the (Fish) Salesmen: The Last Kelongs in Southeast Asia |url=https://modernfarmer.com/2014/12/death-fish-salesmen-last-kelongs-southeast-asia/ |access-date=2022-07-11 |website=Modern Farmer |language=en-US}}</ref> 

====Copper-alloy nets====
{{Main|Copper alloys in aquaculture}}

Recently, [[copper alloys]] have become important netting materials in [[aquaculture]]. Copper alloys are [[antimicrobial]], that is, they destroy [[bacteria]], [[viruses]], [[fungi]], [[algae]], and other [[microbes]]. In the [[marine environment]], the antimicrobial/algaecidal properties of copper alloys prevent [[biofouling]], which can briefly be described as the undesirable accumulation, adhesion, and growth of microorganisms, plants, [[algae]], [[Tube worm (body plan)|tube worms]], [[barnacles]], [[mollusks]], and other organisms.<ref>{{Cite web|url=https://www.manoramaonline.com/karshakasree/farm-management/2017/04/26/fish-cage-farming-by-manoj.html|title=ഓരുവെള്ളത്തിലെ രുചിയേറും വരുമാനം|website=ManoramaOnline|language=ml}}</ref>

The resistance of organism growth on copper alloy nets also provides a cleaner and healthier environment for farmed fish to grow and thrive. Traditional netting involves regular and labor-intensive cleaning. In addition to its antifouling benefits, copper netting has strong structural and corrosion-resistant properties in marine environments.<ref>{{Cite journal |last1=dos Santos |first1=Ana Paula |last2=Hage Seta |first2=Jéssica Helena |last3=Kuhnen |first3=Vanessa Villanova |last4=Sanches |first4=Eduardo Gomes |date=2020-11-01 |title=Antifouling alternatives for aquaculture in tropical waters of the Atlantic Ocean |journal=Aquaculture Reports |language=en |volume=18 |pages=100477 |doi=10.1016/j.aqrep.2020.100477 |s2cid=224842700 |issn=2352-5134|doi-access=free |bibcode=2020AqRep..1800477D }}</ref>

Copper-zinc brass alloys are deployed in commercial-scale aquaculture operations in Asia, South America, and USA (Hawaii). Extensive research, including demonstrations and trials, are being implemented on two other copper alloys: copper-nickel and copper-silicon. Each of these alloy types has an inherent ability to reduce biofouling, cage waste, disease, and the need for antibiotics, while simultaneously maintaining water circulation and oxygen requirements. Other types of copper alloys are also being considered for research and development in aquaculture operations.<ref>{{Cite web |title=Aquaculture – Copper Development Association Africa |url=https://www.copper.co.za/projects/aquaculture/ |access-date=2022-07-11 |language=en-US}}</ref>