View source for Mariculture

{{short description|Marine System}}
[[File:Færøsk havbrug.1.jpg|thumb|Salmon pens off [[Vestmanna]] in the [[Faroe Islands]], an example of [[#Inshore|inshore mariculture]]]]

'''Mariculture''', sometimes called '''marine farming''' or '''marine aquaculture''',<ref>{{Cite web |last=Fisheries |first=NOAA |date=2022-12-29 |title=Understanding Marine Aquaculture {{!}} NOAA Fisheries |url=https://www.fisheries.noaa.gov/insight/understanding-marine-aquaculture |access-date=2024-01-16 |website=NOAA |language=en}}</ref> is a branch of [[aquaculture]] involving the cultivation of [[marine organism]]s for [[food]] and other [[animal product]]s, in [[seawater]].  Subsets of it include ([[offshore aquaculture|offshore mariculture]]), [[fish farm]]s built on [[littoral]] waters ([[#Inshore|inshore mariculture]]), or in [[fish tank|artificial tank]]s, [[fish pond|pond]]s or [[raceway (aquaculture)|raceways]] which are filled with [[seawater]] ([[#Onshore|onshore mariculture]]). An example of the latter is the farming of [[plankton]] and [[seaweed]], [[shellfish]] like [[shrimp]] or [[oysters]], and [[Marine life|marine]] [[finfish]], in saltwater ponds. Non-food products produced by mariculture include: [[fish meal]], [[agar|nutrient agar]], [[jewellery]] (e.g. [[cultured pearl]]s), and [[cosmetics]].

==Types==
===Onshore===
[[File:Microalgae cultivation facility along the Kona Coast of the Big Island of Hawai’i.jpg|thumb|An onshore [[algaculture|microalgae]] cultivation facility in Hawaii<ref name="10.5670/oceanog.2022.213">{{cite journal |last1=Greene |first1=Charles |last2=Scott-Buechler |first2=Celina |last3=Hausner |first3=Arjun |last4=Johnson |first4=Zackary |last5=Lei |first5=Xin Gen |last6=Huntley |first6=Mark |title=Transforming the Future of Marine Aquaculture: A Circular Economy Approach |journal=Oceanography |date=2022 |pages=26–34 |doi=10.5670/oceanog.2022.213 |issn=1042-8275|doi-access=free}}</ref>]]

Although it sounds like a paradox, mariculture is practiced onshore variously in [[fish tank|tank]]s, [[fish pond|pond]]s or [[raceway (aquaculture)|raceways]] which are supplied with [[seawater]].  The distinguishing traits of onshore mariculture are the use of seawater rather than fresh, and that food and nutrients are provided by the water column, not added artificially, a great savings in cost and preservation of the species' natural diet. Examples of onshore mariculture include the farming of [[algaculture|algae]] (including [[plankton]] and [[seaweed]]), [[Marine life|marine]] [[finfish]], and [[shellfish]] (like [[shrimp]] and [[oysters]]), in manmade saltwater ponds.

===Inshore===
[[Image:MH Lochailort.jpg|thumb|Fish cages containing [[salmon]] in [[Loch Ailort]], Scotland, an [[littoral zone|inshore water]]]]

Inshore mariculture is farming marine species such as algae, fish, and shellfish in waters affected by the tide, which include both [[littoral zone|littoral water]]s and their [[estuary|estuarine environments]], such as bays, brackish rivers, and naturally fed and flushing saltwater ponds.

Popular cultivation techniques for inshore mariculture include creating or utilizing artificial reefs,<ref name="abc.net.au-2014-08-15">{{cite web
 | url =http://www.abc.net.au/news/2014-08-15/nrn-abalone-wild-farm/5673010
 | title =First wild abalone farm in Australia built on artificial reef 
 | last =Fitzgerald
 | first =Bridget
 | date =28 August 2014
 | website =Australian Broadcasting Corporation Rural
 | publisher =Australian Broadcasting Corporation
 | access-date =23 April 2016
 }}</ref><ref name="abc.net.au-2016-04-23">{{cite web
 | url =http://www.abc.net.au/news/2016-04-23/world-first-abalone-sea-ranch-creating-opportunity/7345448
 | title =Abalone grown in world-first sea ranch in WA 'as good as wild catch'
 | last =Murphy
 | first =Sean
 | date =23 April 2016
 | website =Australian Broadcasting Corporation News.
 | publisher =Australian Broadcasting Corporation
 | access-date =23 April 2016}}</ref> pens, nets, and long-line arrays of floating cages moored to the bottom.<ref>{{cite web | url=https://www.brookstrapmill.com/product/6-bag-oyster-ranch-squared-bags/ | title=6-bag Oyster Ranch, Squared Bags }}</ref>

As a result of simultaneous global development and evolution over time, the term "ranch" being associated typically with inshore mariculture techniques has proved problematical.  It is applied without any standardized basis to everything from marine species being raised in floating pens, nested within artificial reefs, tended in cages (by the hundreds and even thousands) in long-lined groups, and even [[operant conditioning]] migratory species to return to the waters where they were born for harvesting (also known as "enhanced stocking").{{efn|As is done in Japan where fishermen raise hatchlings in a closely knitted net in a harbor, sounding an underwater horn before each feeding. When the fish are old enough they are freed from the net to mature in the open sea. During spawning season, about 80% of these fish return to their birthplace. The fishermen sound the horn and then net those fish that respond.<ref>Arnason, Ragnar (2001) [http://www.fao.org/docrep/005/y1805e/y1805e07.htm#bm07.1 Ocean Ranching in Japan] In: ''The Economics of Ocean Ranching: Experiences, Outlook and Theory'', FAO, Rome. {{ISBN|92-5-104631-X}}.</ref><ref>{{cite journal|author=Masuda R |author2=Tsukamoto K |year=1998|url=http://www.ingentaconnect.com/content/umrsmas/bullmar/1998/00000062/00000002/art00005 |title=Stock Enhancement in Japan: Review and perspective|journal=Bulletin of Marine Science|volume=62|issue=2|pages=337–358}}</ref><ref>{{cite journal|author=Lindell, Scott |author2=Miner S|author3= Goudey C|author4= Kite-Powell H |author5=Page S |year=2012|url=https://www.fra.affrc.go.jp/bulletin/bull/bull35/35-12.pdf|title=Acoustic Conditioning and Ranching of Black Sea Bass ''Centropristis striata'' in Massachusetts USA|journal=Bull. Fish. Res. Agen.|volume=35|pages=103–110}}</ref>}}

===Open ocean===
Raising marine organisms under controlled offshore in "open ocean" in exposed, high-energy marine environments beyond {{clarification needed span|text=significant coastal influence|reason=This ambiguous wording (which stands as WP:WEASEL WOODS at present) needs both immediate clarification and reliable citation.|date=July 2024}}, is a relatively new{{When|date=September 2022}} approach to mariculture.  Open ocean aquaculture (OOA) uses cages, nets, or long-line arrays that are moored or towed.{{how|reason=How are they towed, by what?  Continuously?  Explanation and reliable citation, please.|date=July 2024}}  Open ocean mariculture has the potential to be combined with offshore energy installation systems, such as [[offshore wind power|wind-farms]], to enable a more effective use of ocean space.<ref>{{Cite book|title=Aquaculture perspective of multi-use sites in the open ocean : the untapped potential for marine resources in the Anthropocene|others=Buck, Bela Hieronymus, Langan, Richard, 1950-|date=6 April 2017|isbn=978-3-319-51159-7|location=Cham, Switzerland|oclc=982656470}}</ref>

Research and commercial open ocean aquaculture facilities are in operation or under development in Panama, Australia, Chile, China, France, Ireland, Italy, Japan, Mexico, and Norway. {{As of|2004}}, two commercial open ocean facilities were operating in U.S. waters, raising [[threadfin]] near [[Hawaii]] and [[cobia]] near [[Puerto Rico]]. An operation targeting [[bigeye tuna]] recently received final approval. All U.S. commercial facilities are currently sited in waters under state or territorial jurisdiction. The largest deep water open ocean farm in the world is raising cobia 12&nbsp;km off the northern coast of Panama in highly exposed sites.<ref name=crs>{{
cite web
 |url=http://ncseonline.org/nle/crsreports/04dec/RL32694.pdf 
 |publisher=[[Congressional Research Service]] 
 |first1=Rachel 
 |last1=Borgatti 
 |first2=Eugene H. 
 |last2=Buck 
 |title=Open Ocean Aquaculture 
 |date=December 13, 2004 
 |access-date=April 10, 2010 
 |url-status=dead 
 |archive-url=https://web.archive.org/web/20090823144656/http://ncseonline.org/nle/crsreports/04dec/RL32694.pdf 
 |archive-date=August 23, 2009 
}}</ref><ref>{{
cite web
|first=Audrey |last=McAvoy
|url=https://abcnews.go.com/Business/wireStory?id=8905220
|title=Hawaii regulators approve first US tuna farm
|work=[[The Associated Press]]
|date=October 24, 2009
|access-date=April 9, 2010
}}</ref>

==Species==
===Algae===
{{Main|Algaculture}}

Algaculture involves the farming of species of [[algae]],<ref name=":1">{{Cite journal |last1=Huesemann |first1=M. |last2=Williams |first2=P. |last3=Edmundson |first3=Scott J. |last4=Chen |first4=P. |last5=Kruk |first5=R. |last6=Cullinan |first6=V. |last7=Crowe |first7=B. |last8=Lundquist |first8=T. |date=September 2017 |title=The laboratory environmental algae pond simulator (LEAPS) photobioreactor: Validation using outdoor pond cultures of Chlorella sorokiniana and Nannochloropsis salina |journal=Algal Research |volume=26 |pages=39–46 |doi=10.1016/j.algal.2017.06.017 |osti=1581797 |issn=2211-9264|doi-access=free |bibcode=2017AlgRe..26...39H }}</ref> including [[microalgae]] (such as [[phytoplankton]]) and [[macroalgae]] (such as [[seaweed]]).

Uses of commercial and industrial algae cultivation include production of [[nutraceutical]]s such as [[omega-3 fatty acids]] (as algal oil)<ref>{{cite journal |last1=Lane |first1=Katie |last2=Derbyshire |first2=Emma |last3=Li |first3=Weili |last4=Brennan |first4=Charles |title=Bioavailability and Potential Uses of Vegetarian Sources of Omega-3 Fatty Acids: A Review of the Literature |journal=Critical Reviews in Food Science and Nutrition |date=January 2014 |volume=54 |issue=5 |pages=572–579 |doi=10.1080/10408398.2011.596292|pmid=24261532 |s2cid=30307483 }}</ref><ref>{{cite book |last1=Winwood |first1=R.J. |chapter=Algal oil as a source of omega-3 fatty acids |title=Food Enrichment with Omega-3 Fatty Acids |date=2013 |series=Woodhead Publishing Series in Food Science, Technology and Nutrition |pages=389–404 |doi=10.1533/9780857098863.4.389|isbn=978-0-85709-428-5 }}</ref><ref>{{cite journal |last1=Lenihan-Geels |first1=Georgia |last2=Bishop |first2=Karen |last3=Ferguson |first3=Lynnette |title=Alternative Sources of Omega-3 Fats: Can We Find a Sustainable Substitute for Fish? |journal=Nutrients |date=18 April 2013 |volume=5 |issue=4 |pages=1301–1315 |doi=10.3390/nu5041301|pmid=23598439 |pmc=3705349 |doi-access=free }}</ref> or natural food [[colorants]] and [[dyes]], [[food]], [[fertilizer]]s, [[bioplastics]], chemical feedstock (raw material), protein-rich animal/[[Commercial fish feed|aquaculture]] feed, [[pharmaceuticals]], and [[algal fuel]],<ref name="10.1007/s43615-021-00084-3">{{cite journal |last1=Venkatesh |first1=G. |title=Circular Bio-economy—Paradigm for the Future: Systematic Review of Scientific Journal Publications from 2015 to 2021 |journal=Circular Economy and Sustainability |date=1 March 2022 |volume=2 |issue=1 |pages=231–279 |doi=10.1007/s43615-021-00084-3 |s2cid=238768104 |language=en |issn=2730-5988|doi-access=free |bibcode=2022CirES...2..231V }}</ref> and can also be used as a means of [[pollution control]] and [[Nature-based solutions|natural]] [[Carbon sequestration#Seaweed farming and algae|carbon sequestration]].<ref name="10.3389/fnut.2022.1029841">{{cite journal |last1=Diaz |first1=Crisandra J. |last2=Douglas |first2=Kai J. |last3=Kang |first3=Kalisa |last4=Kolarik |first4=Ashlynn L. |last5=Malinovski |first5=Rodeon |last6=Torres-Tiji |first6=Yasin |last7=Molino |first7=João V. |last8=Badary |first8=Amr |last9=Mayfield |first9=Stephen P. |title=Developing algae as a sustainable food source |journal=Frontiers in Nutrition |date=2023 |volume=9 |doi=10.3389/fnut.2022.1029841 |pmid=36742010 |pmc=9892066 |issn=2296-861X|doi-access=free}}</ref>

Mariculture of seaweeds can be conducted in the open ocean to regenerate decimated fish populations by providing both habitat and the basis of a [[trophic pyramid]] for marine life.<ref>{{Cite book |last=Flannery, Tim F. (Tim Fridtjof), 1956- |title=Sunlight and seaweed : an argument for how to feed, power and clean up the world |date=31 July 2017 |isbn=978-1-925498-68-4 |location=Melbourne |oclc=987462317}}</ref> Natural seaweed ecosystems can possibly be replicated in the open ocean by creating growth conditions. Von Hertzen, Gamble, and others propose that this practice could be considered to be permaculture and thereby constitute [[marine permaculture]].<ref>{{Cite book |title=Drawdown : the most comprehensive plan ever proposed to reverse global warming |others=Hawken, Paul |year=2017 |isbn=978-0-14-313044-4 |location=New York, New York |oclc=957139166}}</ref><ref>{{cite AV media |title=2040 |date=May 23, 2019 |medium=Motion picture |publisher=Good Things Productions |location=Australia |people=Gameau, Damon (Director)}}</ref><ref>{{Cite web |last=Von Herzen |first=Brian |date=June 2019 |title=Reverse Climate Change with Marine Permaculture Strategies for Ocean Regeneration |url=https://www.youtube.com/watch?v=9Ch65gqD1g4 |url-status=live |archive-url=https://ghostarchive.org/varchive/youtube/20211211/9Ch65gqD1g4 |archive-date=2021-12-11 |website=Youtube}}{{cbignore}}</ref><ref>{{Cite web |last=Powers |first=Matt |date=10 July 2019 |title=Marine Permaculture with Brian Von Herzen Episode 113 A Regenerative Future |url=https://www.youtube.com/watch?v=ZJLHJJNBsVI |url-status=live |archive-url=https://ghostarchive.org/varchive/youtube/20211211/ZJLHJJNBsVI |archive-date=2021-12-11 |website=Youtube}}{{cbignore}}</ref><ref>{{Cite web |date=December 2019 |title=Marine Permaculture with Dr Brian von Herzen & Morag Gamble |url=https://www.youtube.com/watch?v=y8RojQZbsB8 |url-status=live |archive-url=https://ghostarchive.org/varchive/youtube/20211211/y8RojQZbsB8 |archive-date=2021-12-11 |website=Youtube}}{{cbignore}}</ref> The concept envisions using artificial upwelling and floating, submerged platforms as substrate to replicate natural seaweed ecosystems.<ref>{{Cite web |title=Climate Foundation: What is Marine Permaculture? |url=https://www.climatefoundation.org/what-is-marine-permaculture.html |access-date=2020-07-05 |website=Climate Foundation |language=en}}</ref> Following the principles of permaculture, seaweeds and fish from marine permaculture arrays can be sustainably harvested with the potential of sequestering atmospheric carbon, should seaweeds sink below a depth of one kilometer. As of 2020, successful trials had taken place in Hawaii, the Philippines, Puerto Rico and Tasmania.<ref>{{Cite web |title=Climate Foundation: Marine Permaculture |url=https://www.climatefoundation.org/marine-permaculture.html |access-date=2020-07-05 |website=Climate Foundation |language=en}}</ref><ref>{{Cite web |title=Assessing the Potential for Restoration and Permaculture of Tasmania's Giant Kelp Forests - Institute for Marine and Antarctic Studies |url=https://www.imas.utas.edu.au/research/ecology-and-biodiversity/projects/projects/assessing-the-potential-for-restoration-and-permaculture-of-tasmanias-giant-kelp-forests |access-date=2020-07-05 |website=Institute for Marine and Antarctic Studies - University of Tasmania, Australia |language=en-AU}}</ref><ref>{{Cite web |date=2019-11-11 |title=Seaweed researchers plant kelp tolerant of warmer waters |url=https://www.abc.net.au/news/rural/2019-11-11/seaweed-scientists-replanting-giant-kelp-forests/11680194 |access-date=2020-07-05 |website=www.abc.net.au |language=en-AU}}</ref> The idea received substantial public attention, notably featuring as a key solution covered by [[Damon Gameau]]’s documentary [[2040 (film)|''2040'']] and in the book [[Drawdown (book)|''Drawdown: The Most Comprehensive Plan Ever Proposed to Reverse Global Warming'']].
===Shellfish===
Similarly to [[algae]] cultivation, shellfish can be farmed in multiple ways in both onshore and inshore mariculture: on ropes, in bags or cages, or directly on (or within) the bottom. Shellfish mariculture does not require feed or fertilizer inputs, nor insecticides or antibiotics, making shellfish mariculture a [[self-sustainability|self-supporting]] system.<ref>{{cite book|last= McWilliams|first= James|title= Food Only|year= 2009|publisher= Little, Brown and Company|location= New York|isbn= 978-0-316-03374-9}}</ref> Seed for shellfish cultivation is typically produced in commercial hatcheries, or by the farmers themselves.  Among shellfish types raised by mariculture are shrimp, oysters (including artificial pearl cultivation), clams, mussels, abalone.<ref name="oceangrown.com.au-2013">
{{cite web
 |url         = http://www.oceangrown.com.au/wp-content/uploads/2013/10/Ocean-Grown-Information-Memorandum-Approved-Screen.pdf
 |title       = Information Memorandum, 2013 Ranching of Greenlip Abalone, Flinders Bay – Western Australia
 |website     = Ocean Grown Abalone
 |access-date = 23 April 2016
 |url-status     = dead
 |archive-url  = https://web.archive.org/web/20161010215256/http://www.oceangrown.com.au/wp-content/uploads/2013/10/Ocean-Grown-Information-Memorandum-Approved-Screen.pdf
 |archive-date = 10 October 2016
}}</ref>  Shellfish can also be used in [[integrated multi-trophic aquaculture|integrated multi-species cultivation]] techniques, where shellfish can utilize waste generated by higher [[trophic level | trophic-level]] organisms.

The [[Māori people]] of New Zealand retain traditions of farming shellfish.<ref>
[https://researchcommons.waikato.ac.nz/bitstreams/4a64f007-8bf6-467f-a63a-c5571a038ae4/download Ahumoana tawhito (ancient aquaculture): the translocation of toheroa (Paphies ventricosa) and other marine species by Māori] by Vanessa Rona Taikato (2021).
</ref>

=== Finfish ===
{{expand section|more on how fin fish are raised in marine environments|date=July 2024}}

Finfish species raised in mariculture include [[salmon]], [[cod]], [[scallop]]s, certain species of prawn, [[Homarus gammarus|European lobsters]], abalone and [[sea cucumber]]s.<ref>{{Cite journal|last1=Mustafa|first1=S.|last2=Saad|first2=S.|last3=Rahman|first3=R.A.|date=2003-06-01|title=Species studies in sea ranching: an overview and economic perspectives|url=https://doi.org/10.1023/B:RFBF.0000019478.17950.ab|journal=Reviews in Fish Biology and Fisheries|language=en|volume=13|issue=2|pages=165|doi=10.1023/B:RFBF.0000019478.17950.ab|bibcode=2003RFBF...13..165M |s2cid=36082235|issn=1573-5184|url-access=subscription}}</ref> 

Fish species selected to be raised in saltwater pens do not have any additional artificial feed requirements, as they live off of the naturally occurring nutrients within the water column. Typical practice calls for the [[juvenile (organism)|juveniles]] to be planted on the bottom of the body of water within the pen, which utilize more of the water column within their sea pen as they grow and develop.<ref>{{Cite web|last=Fisheries|first=Agriculture and|date=2012-02-17|title=Sea ranching systems|url=https://www.business.qld.gov.au/industries/farms-fishing-forestry/fisheries/aquaculture/site-selection-production/production-systems/sea-ranching-systems|access-date=2020-12-11|website=www.business.qld.gov.au|language=en-AU}}</ref>

==Environmental effects==
Mariculture has rapidly expanded over the last two decades due to new technology, improvements in formulated feeds, greater biological understanding of farmed species, increased water quality within closed farm systems, greater demand for [[seafood products]], site expansion and government interest.<ref>{{cite journal|author=DeVoe, M.R. |year=1994|title=Aquaculture and the marine environment: policy and management issues and opportunities in the United States|journal= Bull. Natl. Res. Inst. Aquacult.|volume= Supp. 1|pages=111–123}}</ref><ref>{{Cite journal | doi = 10.1016/S0044-8486(03)00474-5| title = Management of environmental impacts of marine aquaculture in Europe| journal = Aquaculture| volume = 226| issue = 1–4| pages = 139–163| year = 2003| last1 = Read | first1 = P. | last2 = Fernandes | first2 = T. | bibcode = 2003Aquac.226..139R}}</ref><ref>Ross, A. (1997). ''Leaping in the Dark: A Review of the Environmental Impacts of Marine Salmon Farming in Scotland and Proposals for Change''. Scottish Environment Link, Perth, Scotland.</ref> As a consequence, mariculture has been subject to some controversy regarding its social and [[environmental impact]]s.<ref>{{Cite journal | doi = 10.1016/S0044-8486(97)00186-5| title = Regulating the local environmental impact of intensive marine fish farming I. The concept of the MOM system (Modelling-Ongrowing fish farms-Monitoring)| journal = Aquaculture| volume = 158| issue = 1–2| pages = 85–94| year = 1997| last1 = Ervik | first1 = A. | last2 = Hansen | first2 = P. K. | last3 = Aure | first3 = J. | last4 = Stigebrandt | first4 = A. | last5 = Johannessen | first5 = P. | last6 = Jahnsen | first6 = T. | bibcode = 1997Aquac.158...85E}}</ref><ref name=jen>Jennings, S., Kaiser, M.J., Reynolds, J.D. (2001). Marine Fisheries Ecology. Blackwell, Victoria.</ref> Commonly identified environmental impacts from marine farms are:

# Wastes from cage cultures;
# Farm escapees and [[invasive species|invasives]];
# [[Genetic pollution]] and disease and parasite transfer;
# [[Habitat (ecology)|Habitat]] modification.

As with most farming practices, the degree of environmental impact depends on the size of the farm, the cultured species, stock density, type of feed, [[hydrography]] of the site, and [[husbandry]] methods.<ref>{{Cite journal | doi = 10.1016/0025-326X(95)00100-2| title = The environmental impact of marine fish culture: Towards a sustainable future| journal = Marine Pollution Bulletin| volume = 31| issue = 4–12| pages = 159–166| year = 1995| last1 = Wu | first1 = R. S. S. | bibcode = 1995MarPB..31..159W}}</ref> The adjacent diagram connects these causes and effects.

===Wastes from cage cultures===
Mariculture of [[finfish]] can require a significant amount of [[fishmeal]] or other high protein food sources.<ref name=jen /> Originally, a lot of fishmeal went to waste due to inefficient feeding regimes and poor digestibility of formulated feeds which resulted in poor [[feed conversion ratio]]s.<ref name=forrest>Forrest B, Keeley N, Gillespie P, Hopkins G, Knight B, Govier D. (2007). Review of the ecological effects of marine finfish aquaculture: final report. Prepared for Ministry of Fisheries. Cawthron Report No. 1285.</ref>

In cage culture, several different methods are used for feeding farmed fish – from simple hand feeding to sophisticated computer-controlled systems with automated food dispensers coupled with ''in situ'' uptake sensors that detect consumption rates.<ref name=black>{{Cite book| editor = Steele, John H.| editor2 = Thorpe, Steve A.| editor3 = Turekian, Karl K.| publisher = Academic Press| doi = 10.1006/rwos.2001.0487| chapter = Mariculture, Environmental, Economic and Social Impacts of| title = Encyclopedia of Ocean Sciences| pages = 1578–1584| year = 2001| last1 = Black| first1 = K. D.| isbn = 9780122274305| chapter-url-access = registration| chapter-url = https://archive.org/details/encyclopediaofoc0000unse| url = https://archive.org/details/encyclopediaofoc0000unse| url-access = registration}}</ref> In coastal fish farms, overfeeding primarily leads to increased disposition of detritus on the seafloor (potentially smothering seafloor dwelling invertebrates and altering the physical environment), while in hatcheries and land-based farms, excess food goes to waste and can potentially impact the surrounding catchment and local coastal environment.<ref name=jen /> This impact is usually highly local, and depends significantly on the settling velocity of waste feed and the current velocity (which varies both spatially and temporally) and depth.<ref name=jen /><ref name=black />

===Farm escapees and invasives===
The impact of escapees from aquaculture operations depends on whether or not there are wild [[conspecifics]] or close relatives in the receiving environment, and whether or not the escapee is reproductively capable.<ref name=black /> Several different mitigation/prevention strategies are currently employed, from the development of infertile [[triploid]]s to land-based farms which are completely isolated from any marine environment.<ref name=kat/><ref>{{cite journal|author=Nell, J.A. |year=2002|title=Farming triploid oysters|journal= Aquaculture |volume=210|issue=1–4|pages= 69–88|doi=10.1016/s0044-8486(01)00861-4|bibcode=2002Aquac.210...69N }}</ref><ref>{{cite journal|last=Pfeiffer |first=T. |year=2010|title=Recirculation Technology: the future of aquaculture |journal=Resource, Engineering & Technology for a Sustainable World |volume=17|issue=3|pages= 7–9}}</ref><ref>{{Cite journal | doi = 10.1111/j.1365-2109.2005.01326.x| title = Growth and mortality of sibling triploid and diploid Sydney rock oysters, Saccostrea glomerata (Gould), in the Camden Haven River| journal = Aquaculture Research| volume = 36| issue = 11| pages = 1093–1103| year = 2005| last1 = Troup | first1 = A. J. | last2 = Cairns | first2 = S. C. | last3 = Simpson | first3 = R. D. | doi-access = free}}</ref> Escapees can adversely impact local ecosystems through [[Hybrid (biology)|hybridization]] and loss of genetic diversity in native stocks, increase negative interactions within an ecosystem (such as [[predation]] and [[competition]]), disease transmission and habitat changes (from [[trophic cascade]]s and ecosystem shifts to varying sediment regimes and thus [[turbidity]]).

The accidental introduction of invasive species is also of concern. Aquaculture is one of the main vectors for invasives following accidental releases of farmed stocks into the wild.<ref name=naylor>{{Cite journal | doi = 10.1126/science.1064875| title = ECOLOGY: Aquaculture--A Gateway for Exotic Species| journal = Science| volume = 294| issue = 5547| pages = 1655–1656| year = 2001| last1 = Naylor | first1 = R. L.| pmid=11721035| s2cid = 82810702}}</ref> One example is the Siberian sturgeon (''Acipenser baerii'') which accidentally escaped from a fish farm into the [[Gironde Estuary]] (Southwest France) following a severe storm in December 1999 (5,000 individual fish escaped into the estuary which had never hosted this species before).<ref>{{Cite journal
 | pmid = 18306893
| year = 2008
| last1 = Maury-Brachet
| first1 = R
| title = The 'storm of the century' (December 1999) and the accidental escape of Siberian sturgeons (Acipenser baerii) into the gironde estuary (southwest France). An original approach for metal contamination
| journal = Environmental Science and Pollution Research International
| volume = 15
| issue = 1
| pages = 89–94
| last2 = Rochard
| first2 = E
| last3 = Durrieu
| first3 = G
| last4 = Boudou
| first4 = A
 | doi=10.1065/espr2007.12.469
| bibcode = 2008ESPR...15...89M
| s2cid = 46148803
}}</ref> [[Mollusc]]an farming is another example whereby species can be introduced to new environments by ‘hitchhiking’ on farmed molluscs. Also, farmed molluscs themselves can become dominate predators and/or competitors, as well as potentially spread pathogens and parasites.<ref name=naylor />

===Genetic pollution, disease, and parasite transfer===
One of the primary concerns with mariculture is the potential for [[disease]] and [[parasite]] transfer. Farmed stocks are often [[selectively bred]] to increase disease and parasite resistance, as well as improving growth rates and quality of products.<ref name=jen /> As a consequence, the [[genetic diversity]] within reared stocks decreases with every generation – meaning they can potentially reduce the genetic diversity within wild populations if they escape into those wild populations.<ref name=forrest /> Such [[genetic pollution]] from escaped aquaculture stock can reduce the wild population's ability to adjust to the changing natural environment. Species grown by mariculture can also harbour diseases and parasites (e.g., lice) which can be introduced to wild populations upon their escape. An example of this is the parasitic [[Sea louse|sea lice]] on wild and farmed Atlantic salmon in Canada.<ref>{{Cite journal | doi = 10.1038/451023a| pmid = 18172486| title = Aquaculture: The price of lice| journal = Nature| volume = 451| issue = 7174| pages = 23–24| year = 2008| last1 = Rosenberg | first1 = A. A. | bibcode = 2008Natur.451...23R| s2cid = 32766703| doi-access = free}}</ref> Also, non-indigenous species which are farmed may have resistance to, or carry, particular diseases (which they picked up in their native habitats) which could be spread through wild populations if they escape into those wild populations. Such ‘new’ diseases would be devastating for those wild populations because they would have no immunity to them.<ref>{{Cite web|title=Wilderness Connect|url=https://wilderness.net/learn-about-wilderness/threats/invasive.php|access-date=2020-11-12|website=wilderness.net|language=en}}</ref>

===Habitat modification===
With the exception of [[benthic]] habitats directly beneath marine farms, most mariculture causes minimal destruction to habitats. However, the destruction of [[mangrove]] forests from the farming of shrimps is of concern.<ref name=jen /><ref name=black /> Globally, shrimp farming activity is a small contributor to the destruction of [[mangrove]] forests; however, locally it can be devastating.<ref name=jen /><ref name=black /> [[Mangrove]] forests provide rich matrices which support a great deal of [[biodiversity]] – predominately juvenile fish and crustaceans.<ref name=black /><ref name=kaiser>Kaiser, M.J., Attrill, M.J., Jennings, S., Thomas, D.N., Barnes, D.K.A., Brierley, A.S., Polunin, N.V.C., Raffaelli, D.G., Williams, P.J.le B. (2005). Marine Ecology: Processes, Systems and Impacts. Oxford University Press, New York.</ref> Furthermore, they act as buffering systems whereby they reduce coastal erosion, and improve water quality for in situ animals by processing material and ‘filtering’ sediments.<ref name=black /><ref name=kaiser /><ref>Trujillo, A.P., Thurman, H.V. (2008) Essentials of Oceanography Ninth Edition. Pearson Prentice Hall. New Jersey.</ref>

===Others===
In addition, [[nitrogen]] and [[phosphorus]] compounds from food and waste may lead to blooms of [[phytoplankton]], whose subsequent degradation can drastically reduce [[oxygen]] levels. If the [[algae]] are toxic, [[fish]] are killed and [[shellfish]] contaminated.<ref name=kat/><ref name="multiples"/><ref>{{cite web|publisher=
UNEP, World Fisheries Trust|year=2002|url=http://www.cbd.int/doc/meetings/mar/temctre-01/official/temctre-01-02-en.pdf |title=THE EFFECTS OF MARICULTURE ON BIODIVERSITY}}</ref> These algal blooms are sometimes referred to as harmful algal blooms, which are caused by a high influx of nutrients, such as nitrogen and phosphorus, into the water due to run-off from land based human operations.<ref>{{Cite web|last=US EPA|first=OW|date=2013-06-03|title=Harmful Algal Blooms|url=https://www.epa.gov/nutrientpollution/harmful-algal-blooms|archive-url=https://web.archive.org/web/20131104154039/http://www2.epa.gov/nutrientpollution/harmful-algal-blooms|url-status=dead|archive-date=November 4, 2013|access-date=2020-11-12|website=US EPA|language=en}}</ref>

Over the course of rearing various species, the sediment on bottom of the specific body of water becomes highly metallic with influx of copper, zinc and lead that is being introduced to the area. This influx of these heavy metals is likely due to the buildup of fish waste, uneaten fish feed, and the paint that comes off the boats and floats that are used in the mariculture operations.<ref>{{Cite journal|last1=Liang|first1=Peng|last2=Wu|first2=Sheng-Chun|last3=Zhang|first3=Jin|last4=Cao|first4=Yucheng|last5=Yu|first5=Shen|last6=Wong|first6=Ming-Hung|date=2016-04-01|title=The effects of mariculture on heavy metal distribution in sediments and cultured fish around the Pearl River Delta region, south China|url=http://www.sciencedirect.com/science/article/pii/S0045653515303052|journal=Chemosphere|language=en|volume=148|pages=171–177|doi=10.1016/j.chemosphere.2015.10.110|pmid=26807936|bibcode=2016Chmsp.148..171L|issn=0045-6535|url-access=subscription}}</ref>

==Sustainability==
Mariculture development may be sustained by basic and applied research and development in major fields such as [[nutrition]], [[genetics]], system management, product handling, and [[socioeconomics]]. One approach uses closed systems that have no direct interaction with the local environment.<ref name=schwermer>
{{Cite journal | doi = 10.1111/j.1574-6941.2010.00865.x | title = Effect of nitrate on sulfur transformations in sulfidogenic sludge of a marine aquaculture biofilter | journal = FEMS Microbiology Ecology | volume = 72 | issue = 3 | pages = 476–84 | year = 2010 | last1 = Schwermer 
 | first1 = C. U. | last2 = Ferdelman | first2 = T. G. | last3 = Stief | first3 = P. | last4 = Gieseke | first4 = A. | last5 = Rezakhani | first5 = N. | last6 = Van Rijn | first6 = J. | last7 = De Beer | first7 = D. | last8 = Schramm | first8 = A. | pmid=20402774| doi-access = free | bibcode = 2010FEMME..72..476S | hdl = 21.11116/0000-0001-CADE-2 | hdl-access = free }}
</ref>
However, investment and operational cost are currently significantly higher than with open cages, limiting closed systems to their current role as hatcheries.<ref name=kat/> Many studies have estimated that [[seafood]] will run out by 2048.<ref>{{Cite journal |last=Stokstad |first=Erik |date=2006-11-03 |title=Global Loss of Biodiversity Harming Ocean Bounty |url=https://www.science.org/doi/10.1126/science.314.5800.745 |journal=Science |language=en |volume=314 |issue=5800 |pages=745 |doi=10.1126/science.314.5800.745 |pmid=17082432 |issn=0036-8075|url-access=subscription }}</ref> Farmed fish will also become crucial to feeding the growing human population that will potentially reach 9.8 billion by 2050. <ref name=":0">{{Cite journal |last1=Costello |first1=Christopher |last2=Cao |first2=Ling |last3=Gelcich |first3=Stefan |last4=Cisneros-Mata |first4=Miguel Á. |last5=Free |first5=Christopher M. |last6=Froehlich |first6=Halley E. |last7=Golden |first7=Christopher D. |last8=Ishimura |first8=Gakushi |last9=Maier |first9=Jason |last10=Macadam-Somer |first10=Ilan |last11=Mangin |first11=Tracey |last12=Melnychuk |first12=Michael C. |last13=Miyahara |first13=Masanori |last14=de Moor |first14=Carryn L. |last15=Naylor |first15=Rosamond |date=2020-12-03 |title=The future of food from the sea |url=https://www.nature.com/articles/s41586-020-2616-y |journal=Nature |language=en |volume=588 |issue=7836 |pages=95–100 |doi=10.1038/s41586-020-2616-y |pmid=32814903 |bibcode=2020Natur.588...95C |issn=0028-0836|hdl=11093/1616 |hdl-access=free }}</ref> 

==Benefits==
Sustainable mariculture promises economic and environmental benefits. Economies of scale imply that ranching can produce fish at lower cost than industrial fishing, leading to better human diets and the gradual elimination of unsustainable fisheries. Consistent supply and quality control has enabled integration in food market channels.<ref name=kat>{{cite journal|author=Katavic, Ivan|year=1999|url=http://www.agr.hr/smotra/pdf/acs64_25.pdf|title=Mariculture in the New Millennium|journal=Agriculturae Conspectus Scientificus|pages=223–229|volume=64|issue=3|archive-date=2007-06-27|access-date=2009-06-27|archive-url=https://web.archive.org/web/20070627001057/http://www.agr.hr/smotra/pdf/acs64_25.pdf|url-status=dead}}</ref><ref name="multiples">{{Cite journal | doi = 10.1080/13657309909380229| title = Green grow the fishes-oh? Environmental attributes in marketing aquaculture products| journal = Aquaculture Economics & Management| volume = 3| pages = 7–17| year = 1999| last1 = Young | first1 = J. A. | last2 = Brugere | first2 = C. | last3 = Muir | first3 = J. F. | issue = 1| bibcode = 1999AqEM....3....7Y}}</ref><ref name=":0" />

==Technology and practices==
{{empty section|date=March 2025}}

==List of species farmed==
{{incomplete list|date=June 2019}}

;Fish
{{div col|colwidth=30em}}
* [[European sea bass]]
* [[Bigeye tuna]]
* [[Cobia]]
* [[Grouper]]
* [[Lutjanidae|Snapper]]
* [[Pompano]]
* [[Salmon]]
* [[Pearlspot]]
* [[Yellowtail jack]]
* [[Mullet (fish)|Mullet]]
* [[Pomfret]]
* [[Barramundi]]<ref name="mj">{{cite web|title=The Bizarre and Inspiring Story of Iowa's Fish Farmers
|url=https://www.motherjones.com/environment/2017/01/barramundi-aquaculture-fish-farm-iowa-veroblue |work=Mother Jones|access-date=18 May 2017 |first=Maddie |last=Oatman |date=Jan–Feb 2017}}</ref>
{{div col end}}
;Shellfish/Crustaceans
{{div col|colwidth=30em}}
* [[Abalone]]
* [[Oysters]]
* [[Prawn]]
* [[Mussels]]
{{div col end}}
;Plants
* [[Seaweeds]]<ref name=crs/><ref>{{Cite journal | doi = 10.1016/j.aquaculture.2006.12.017| title = Management of productivity, environmental effects and profitability of shellfish aquaculture — the Farm Aquaculture Resource Management (FARM) model| journal = Aquaculture| volume = 264| issue = 1–4| pages = 160–174| year = 2007| last1 = Ferreira | first1 = J. G. | last2 = Hawkins | first2 = A. J. S. | last3 = Bricker | first3 = S. B. | bibcode = 2007Aquac.264..160F}}</ref>

==Scientific literature==
Scientific literature on mariculture can be found in the following journals:
{{Refbegin|2}}
* ''[[Applied and Environmental Microbiology]]''
* ''[[Aquaculture (journal)|Aquaculture]]''
* ''[[Aquaculture Research]]''
* ''[[Journal of Marine Science]]''
* ''[[Marine Resource Economics]]''
* ''[[Ocean Shoreline Management]]''
* ''[[Journal of Applied Phycology]]''
* ''[[Journal of Experimental Marine Biology and Ecology]]''
* ''[[Journal of Phycology]]''
* ''[[Journal of Shellfish Research]]''
* ''[[Reviews in Fish Biology and Fisheries]]''
* ''[[Reviews in Fisheries Science]]''
{{Refend}}

==Notes==
{{notelist}}

==See also==
{{div col|colwidth=30em}}
* [[Aquaculture]]
* [[Fish farming]]
* [[Hydroponics]]
* [[Algaculture]]
* [[Oyster farming]]
* [[Aquaponics]]
* [[Copper alloys in aquaculture]]
* [[Integrated Multi-Trophic Aquaculture]]
* [[Saltwater aquaponics]]
* [[Seaweed farming]]{{div col end}}

==References==
{{Reflist}}

==External links==
* [http://www.longline.co.uk Longline Environment]
* [https://web.archive.org/web/20081201001755/http://www.worldfishcenter.org/v2/pubs.html Worldfishcenter -provides info on cultivating certain marine organisms]
* [http://www.longline.co.uk Web based aquaculture simulations for shellfish in estuaries and coastal systems]: Simulation modelling for mussels, oysters and clams.
* [http://www.crc.uri.edu/index.php?themeid=1 Mariculture guidelines and best practices]: A coastal management perspective on mariculture development by the University of Rhode Island Coastal Resources Center.
* [http://www.marinebio.net/marinescience/06future/marindex.htm Mariculture] ''Marine Science''. Retrieved 14 January 2010.
* [http://www.flotillaonline.com Flotilla Online] – Apocalyptic fiction novel about a mariculture enterprise in the near-future and hub for mariculture topics.

{{Fishing industry topics|expanded=aquaculture}}
{{Fisheries and fishing}}

{{Authority control}}

[[Category:Aquaculture]]