View source for Integrated multi-trophic aquaculture

{{Short description|Type of aquaculture}}
[[File:IMTA cultured mussels (Mytilus edulis) in the Bay of Fundy Canada.jpg|thumb|300px|right|Blue mussels (''[[Mytilus edulis]]'') cultivated in proximity to Atlantic salmon (''[[Salmo salar]]'') in the [[Bay of Fundy]], [[Canada]]. ''Note the salmon cage (polar circle) in the background''.|alt=Photo of man in front of  a railing, squatting on a metal grate above water holding cluster of hundreds of mussels. Behind the railing is a circular pond several 10s of feet in diameter.]]

'''Integrated multi-trophic aquaculture''' ('''IMTA''') is a type of [[aquaculture]] where the [[By-product|byproducts]], including [[waste]], from one aquatic species are used as inputs ([[fertilizer]]s, [[food]]) for another. Farmers combine fed [[aquaculture]] (e.g., [[fish]], [[shrimp]]) with inorganic extractive (e.g., [[seaweed]]) and organic extractive (e.g., [[shellfish]]) aquaculture to create balanced systems for environment remediation ([[biomitigation]]), economic stability (improved output, lower cost, [[Diversification (marketing strategy)|product diversification]] and risk reduction) and social acceptability (better management practices).<ref name="Chopin et al. 2001">{{cite journal
|author1=Chopin T |author2=Buschmann A.H. |author3=Halling C. |author4=Troell M. |author5=Kautsky N. |author6=Neori A. |author7=Kraemer G.P. |author8=Zertuche-Gonzalez J.A. |author9=Yarish C. |author10=Neefus C. |year=2001
|title=Integrating seaweeds into marine aquaculture systems: a key toward sustainability
|journal=Journal of Phycology
|volume=37
|issue=6 |pages=975–986
|doi=10.1046/j.1529-8817.2001.01137.x |bibcode=2001JPcgy..37..975C |s2cid=85161308 }}</ref>

Selecting appropriate species and sizing the various populations to provide necessary ecosystem functions allows the biological and chemical processes involved to achieve a stable balance, mutually benefiting the organisms and improving [[ecosystem health]].

Ideally, the co-cultured species each yield valuable commercial "crops".<ref name="Chopin 2006"/> IMTA can [[synergy|synergistically]] increase total output, even if some of the crops yield less than they would, short-term, in a [[monoculture]].<ref name="Neori et al. 2004">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.</ref> 

IMTA is also highly beneficial for reducing the environmental footprint of aquaculture. The growth of farmed Atlantic salmon (''Salmo salar''), provides insight to the rapid growth of aquaculture demand. Output growth rates averaged 25.6% from 1980 to 2004, with the economic value of farmed salmon output exceeding 4 billion U.S. dollars in 2004.<ref name=":0">{{Cite web |title=(PDF) Integrated Multi-Trophic Aquaculture (IMTA): a potential strategic choice for farmers |url=https://www.researchgate.net/publication/240238159_Integrated_Multi-Trophic_Aquaculture_IMTA_a_potential_strategic_choice_for_farmers |archive-url=http://web.archive.org/web/20240707093058/https://www.researchgate.net/publication/240238159_Integrated_Multi-Trophic_Aquaculture_IMTA_a_potential_strategic_choice_for_farmers |archive-date=2024-07-07 |access-date=2025-02-17 |website=ResearchGate |language=en}}</ref> IMTA works by creating a closed-loop system where the by-products such as excess nutrients and organic waste from fish farming, are utilized by other species such as shellfish and seaweed. This process can decrease water pollution, minimize the need for chemical fertilizers, and improve overall ecosystem health. Furthermore, by integrating different trophic levels, IMTA can enhance biodiversity and promote more sustainable practices in marine food production.

==Terminology and related approaches==

"Integrated" refers to intensive and synergistic cultivation, using water-borne nutrient and energy transfer. "Multi-trophic" means that the various species occupy different [[trophic level]]s, i.e., different (but adjacent) links in the [[food chain]].<ref name="Chopin 2006">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.</ref>

IMTA is a specialized form of the age-old practice of aquatic [[polyculture]], which was the co-culture of various species, often without regard to trophic level. In this broader case, the organisms may share biological and chemical processes that may be minimally [[:wikt:complementary|complementary]], potentially leading to reduced production of both species due to competition for the same food resource. However, some traditional systems such as polyculture of [[Carp|carps]] in China employ species that occupy multiple [[Ecological niche|niche]]s within the same pond, or the culture of fish that is integrated with a terrestrial agricultural [[species]], can be considered forms of IMTA.<ref>Ruddle, K. and V. Christensen. 1993. An energy flow model of the mulberry dike-carp pond farming system of the Zhujiang Delta, Guangdong Province, China. pp. 48-55. In: V. Christensen ans D. Pauley, (eds.) ''Trophic Models of Aquatic Ecosystems'' ICLARM Conference Proceedings 26, 390pp.</ref>  

The more general term "Integrated Aquaculture" is used to describe the integration of monocultures through water transfer between the culture systems.<ref name="Neori et al. 2004"/> The terms "IMTA" and "integrated aquaculture" differ primarily in their precision and are sometimes interchanged. [[Aquaponics]], fractionated aquaculture, integrated agriculture-aquaculture systems, integrated peri-urban-aquaculture systems, and integrated fisheries-aquaculture systems are all variations of the IMTA concept.

==Range of approaches==
Today, low-intensity traditional/incidental multi-trophic aquaculture is much more common than modern IMTA.<ref name="Neori et al. 2004"/> Most are relatively simple, such as fish, seaweed or shellfish.

True IMTA can be land-based, using [[Pond|ponds]] or tanks, or even open-water [[Marine (ocean)|marine]] or [[freshwater]] systems. Implementations have included species combinations<ref name="Neori et al. 2004"/> such as shellfish/shrimp, [[fish]]/seaweed/shellfish, fish/seaweed, fish/shrimp and seaweed/shrimp.<ref name="Troell et al. 2003">Troell M, Halling C, Neori A, Chopin T, Buschmann AH, Kautsky N and Yarish C. 2003. Integrated mariculture: asking the right questions. Aquaculture 226: 69-90.</ref>   

IMTA in open water ([[Offshore aquaculture|offshore cultivation]]) can be done by the use of [[Buoy|buoys]] with lines on which the seaweed grows. The buoys/lines are placed next to the fishnets or cages in which the fish grows.<ref>{{cite web|url=http://www.zeewierwijzer.nl/posts/het-is-gedaan-met-de-andijvie-51.html|title=Seaweed/fish cultivation in offshore systems|url-status=dead|archive-url=https://web.archive.org/web/20141113183639/http://www.zeewierwijzer.nl/posts/het-is-gedaan-met-de-andijvie-51.html|archive-date=2014-11-13}}</ref> In some tropical Asian countries some traditional forms of aquaculture of [[finfish]] in floating cages, nearby fish and shrimp ponds, and [[oyster]] farming integrated with some capture fisheries in estuaries can be considered a form of IMTA.<ref>Rice, M.A. and A.Z. DeVera (1998). Aquaculture in Dagupan City. World Aquaculture 29(1):18-24.</ref>  Since 2010, IMTA has been used commercially in Norway, Scotland, and Ireland.

In the future, systems with other components for additional functions, or similar functions but different size brackets of particles<!--what is a size bracket of particles?-->, are likely.<ref name="Chopin 2006"/>  Multiple regulatory issues remain open.<ref name="Chopin et al. 2004">Chopin T, Robinson S, Sawhney M, Bastarache S, Belyea E, Shea R, Armstrong W, Stewart and Fitzgerald P. 2004. The AquaNet integrated multi-trophic aquaculture project: rationale of the project and development of kelp cultivation as the inorganic extractive component of the system. Bulletin of the Aquaculture Association of Canada. 104(3): 11-18.</ref>

==Modern history of land-based systems==
Ryther and co-workers created modern, integrated, intensive, land mariculture.<ref name="Goldman et al. 1974">Goldman JC, Tenore RK, Ryther HJ and Corwin N. 1974. Inorganic nitrogen removal in a combined tertiary treatment - marine aquaculture system: I. Removal efficiencies. Water Research 8: 45-54.</ref><ref name="Ryther et al. 1975">Ryther JH, Goldman JC, Gifford JE, Huguenin JE, Wing AS, Clarner JP, Williams LD andLapointe BE. 1975. Physical models of integrated waste recycling -  marine polyculture systems. Aquaculture 5: 163-177.</ref> They originated, both theoretically and experimentally, the integrated use of extractive organisms&mdash;shellfish, [[microalgae]] and seaweeds&mdash;in the treatment of household [[effluent]]s, descriptively and with quantitative results. A domestic [[wastewater]] effluent, mixed with seawater, was the nutrient source for [[phytoplankton]], which in turn became food for [[oyster]]s and [[clam]]s. They cultivated other organisms in a [[food chain]] rooted in the farm's organic sludge. Dissolved nutrients in the final effluent were filtered by seaweed (mainly [[Gracilaria]] and [[Sea lettuce|Ulva]]) [[Biofilter|biofilters]]. The value of the original organisms grown on human waste effluents was minimal.

In 1976, Huguenin proposed adaptations to the treatment of intensive aquaculture effluents in both inland and coastal areas.<ref name="Huguenin, 1976">Huguenin JH. 1976. An examination of problems and potentials for future large-scale intensive seaweed culture systems. Aquaculture 9: 313-342.</ref> Tenore followed by integrating with their system of carnivorous fish and the [[algivore|macroalgivore]] [[abalone]].<ref name="Tenore 1976">Tenore KR. 1976. Food chain dynamics of abalone in a polyculture system. Aquaculture 8: 23–27.</ref>

In 1977, Hughes-Games<ref name="Hughes-Games (1977)">Hughes-Games WL. 1977. Growing the Japanese oyster (Crassostrea gigas) in sub-tropical seawater fishponds: I. Growth rate, survival and quality index. Aquaculture 11: 217-229.</ref> described the first practical marine fish/shellfish/phytoplankton culture, followed by Gordin, et al., in 1981.<ref name="Gordin et al. (1981)">Gordin H, Motzkin F, Hughes-Games A and Porter C. 1981. Seawater mariculture pond - an integrated system. European Aquaculture Society Special Publication 6: 1-13.</ref> By 1989, a semi-intensive (1&nbsp;kg fish/m<sup>−3</sup>) [[seabream]] and [[Mugil cephalus|grey mullet]] pond system by the [[Gulf of Aqaba]] ([[Eilat]]) on the [[Red Sea]] supported dense [[diatom]] populations, excellent for feeding [[oysters]].<ref name="Neori et al. (1989)">Neori A, Krom MD, Cohen Y and Gordin H. 1989. Water quality conditions and particulate chlorophyll a of new intensive seawater fishpond in Eilat, Israel: daily and dial variations. Aquaculture 80: 63-78.</ref><ref name="Erez et al., 1990">Erez J, Krom MD and Neuwirth T. 1990. Daily oxygen variations in marine fish ponds, Eilat, Israel. Aquaculture 84: 289-305.</ref> Hundreds of kilos of fish and oysters cultured here were sold. Researchers also quantified the water quality parameters and nutrient budgets in (5&nbsp;kg fish m<sup>−3</sup>) green water seabream ponds.<ref name="Neori et al. (1989)"/><ref name="Krom and Neori (1989)">Krom MD and Neori A. 1989. A total nutrient budget for an experimental intensive fishpond with circularly moving seawater. Aquaculture 88: 345-358.</ref> The phytoplankton generally maintained reasonable water quality and converted on average over half the waste nitrogen into algal [[biomass]]. Experiments with intensive [[bivalve]] cultures yielded high bivalve growth rates.<ref name="Shpigel and Friedman, 1990">Shpigel M and Fridman R. 1990. Propagation of the Manila clam Tapes semidecussatus in the effluent of marine aquaculture ponds in Eilat, Israel. Aquaculture 90: 113-122.</ref><ref name="Shpigel and Blaylock, 1991">Shpigel M and BlaylockRA. 1991. The Pacific oyster, Crassostrea gigas, as a biological filter for a marine fish aquaculture pond. Aquaculture 92: 187-197.</ref><ref name="Shpigel et al., 1993a">Shpigel M, Neori A, Popper DM and Gordin H. 1993a. A proposed model for ''environmentally clean'' landbased culture of fish, bivalves and seaweeds. Aquaculture 117: 115-128.</ref><ref name="Shpigel et al., 1993b">Shpigel M, Lee J, Soohoo B, Fridman R and Gordin H. 1993b. The use of effluent water from fish ponds as a food source for the pacific oyster Crassostrea gigas Tunberg. Aquaculture & Fisheries Management 24: 529-543.</ref><ref name="Neori and Shpigel, 1999">Neori A and Shpigel M. 1999. Algae treat effluents and feed invertebrates in sustainable integrated mariculture. World Aquaculture 30: 46-49, 51.</ref><ref name="Neori et al., 2001">Neori A, Shpigel M and Scharfstein B. 2001. Land-based low-pollution integrated mariculture of fish, seaweed and herbivores: principles of development, design, operation and economics. European Aquaculture Society Special Publication 29: 190-191.</ref> This technology supported a small farm in southern Israel.

==Sustainability==
IMTA promotes economic and environmental [[sustainability]] by converting byproducts and uneaten feed from fed organisms into harvestable crops, thereby reducing [[eutrophication]], and increasing economic diversification.<ref name="Neori et al. 2004"/><ref name="Troell et al. 2003"/><ref name="Tournay 2006">Tournay B. 2006. IMTA: template for production? Fish Farming International, Vol. 33, No. 5, May 2006, pg. 27.</ref>

Properly managed multi-trophic aquaculture accelerates growth without detrimental side-effects.<ref name="Chopin et al. 2004"/><ref name="Johnson 2004">Johnson E. 2004. Cleaning up the sea cages. In: Family Jewels. Saltscapes, Vol. 5, No. 3, May/June 2004, 44-48.</ref><ref name="Lander et al. 2004">Lander T, Barrington K, Robinson S, MacDonald B and Martin J. 2004. Dynamics of the blue mussel as an extractive organism in an integrated multi-trophic aquaculture system. Bulletin of the Aquaculture Association of Canada. 104(3): 19-28.</ref><ref name="Ridler et al. 2006">Ridler N, Robinson B, Chopin T, Robinson S and Page F. 2006. Development of integrated multi-trophic aquaculture in the Bay of Fundy, Canada:  a socio-economic case study. World Aquaculture 37(3): 43-48.</ref> This increases the site's ability to assimilate the cultivated organisms, thereby reducing negative environmental impacts.<!--how does it do that? the site isn't changing, just the stressors.-->

IMTA enables farmers to diversify their output by replacing purchased inputs with byproducts from lower trophic levels, often without new sites. Initial economic research suggests that IMTA can increase profits and can reduce financial risks due to weather, disease and market fluctuations.<ref name="Ridler et al. 2007">Ridler N, Wowchuk M, Robinson B, Barrington K, Chopin T, Robinson S, Page F, Reid G and Haya K. 2007. Integrated multi-trophic aquaculture (IMTA): a potential strategic choice for farmers. Aquaculture Economics & Management 11: 99-110.</ref> Over a dozen studies have investigated the economics of IMTA systems since 1985.<ref name="Neori et al. 2004"/>

The economic sustainability of IMTA is enhanced through diversification. By cultivating multiple species, farmers can spread their economic risk and gain multiple sources of revenue. For example, if the market demand for one species drops, farmers can rely on the production of other species, such as shellfish or seaweed. This reduces the economic vulnerability that is typically associated with monoculture systems. Additionally, the diverse production of food and raw materials further contributes to the system's long-term economic viability. <!-- yes, but what do they conclude? and do they quantify anything?-->

==Nutrient flow ==
Typically, carnivorous fish or shrimp occupy IMTA's higher [[trophic level]]s. They excrete soluble [[ammonia]] and [[phosphorus]] (ortho[[phosphate]]). Seaweeds and similar species can extract these inorganic nutrients directly from their environment.<ref name="Chopin et al. 2001"/><ref name="Neori et al. 2004"/><ref name="Troell et al. 2003"/> Fish and shrimp also release organic nutrients which feed shellfish and [[deposit feeders]].<ref name="Troell et al. 2003"/><ref name="Lander et al. 2004"/><ref name="Mazzola and Sarà 2001">Mazzola A and Sarà G. 2001. The effect of fish farming organic waste on food availability for bivalve molluscs (Gaeta Gulf, Central Tyrrhenian, MED): stable carbon isotopic analysis. Aquaculture 192: 361-379.</ref>

Species such as shellfish that occupy intermediate trophic levels often play a dual role, both filtering organic bottom-level organisms from the water and generating some ammonia.<ref name="Troell et al. 2003"/> Waste feed may also provide additional nutrients; either by direct consumption or via [[decomposition]] into individual nutrients. In some projects, the waste nutrients are also gathered and reused in the food given to the fish in cultivation. This can happen by processing the seaweed grown into food.<ref>{{cite web|url=http://www.zeewierwijzer.nl/posts/het-is-gedaan-met-de-andijvie-51.html|title=Reuse of waste nutrients as fish food|url-status=dead|archive-url=https://web.archive.org/web/20141113183639/http://www.zeewierwijzer.nl/posts/het-is-gedaan-met-de-andijvie-51.html|archive-date=2014-11-13}}</ref>

IMTA systems can significantly improve nutrient recovery efficiency. This is especially crucial in regions where conventional monoculture farming leads to nutrient imbalances, contributing to eutrophication and dead zones. Shellfish, such as mussels and oysters, filter out excess nitrogen and phosphorus from the water, while seaweed absorbs carbon dioxide and releases oxygen, fostering better water quality and a more stable marine environment. <ref name=":0" />

=== Recovery efficiency ===
Nutrient recovery efficiency is a function of technology, harvest schedule, management, spatial configuration, production, species selection, trophic level [[biomass]] ratios, natural food availability, particle size, digestibility, season, light, temperature, and water flow.<ref name="Neori et al. 2004"/><ref name="Troell et al. 2003"/><ref name="Mazzola and Sarà 2001"/> Since these factors significantly vary by site and region, recovery efficiency also varies.

In a hypothetical family-scale fish/microalga /bivalve/seaweed farm, based on pilot scale data, at least 60% of nutrient input reached commercial products, nearly three times more than in modern net pen farms. Expected average annual yields of the system for a hypothetical {{convert|1|ha}} were {{convert|35|t}} of seabream, {{convert|100|t}} of bivalves and {{convert|125|t}} of seaweeds. These results required precise water quality control and attention to suitability for bivalve nutrition, due to the difficulty in maintaining consistent  phytoplankton populations.<ref name="Neori et al. 2004"/><ref name="Krom and Neori (1989)"/><ref name="Shpigel et al., 1993b"/><ref name="Krom et al. 1985">Krom MD, Porter C and Gordin H. 1985. Causes of fish mortalities in the semi-intensively operated seawater ponds in Eilat, Israel. Aquaculture 49: 159-177.</ref>

Seaweeds' nitrogen uptake efficiency ranges from 2-100% in land-based systems.<ref name="Troell et al. 2003"/>  Uptake efficiency in open-water IMTA is unknown.<ref name="Reid et al. 2007">Reid GK, Robinson S, Chopin T, Lander T, MacDonald B, Haya K, Burridge F, Page F, Ridler N, Justason A, Sewuster J, Powell F and Marvin R. An interdisciplinary approach to the development of integrated multi-trophic aquaculture (IMTA): bioenergetics as a means to quantify the effectiveness of IMTA systems and ecosystem response. World Aquaculture Society. Aquaculture 2007 conference proceedings, pg. 761. (https://www.was.org/Meetings/AbstractData.asp?AbstractId=13933 {{Webarchive|url=https://web.archive.org/web/20070927003940/https://www.was.org/Meetings/AbstractData.asp?AbstractId=13933 |date=2007-09-27 }})</ref>

==Food safety and quality==
Feeding the wastes of one species to another has the potential for [[contamination]], although this has yet to be observed in IMTA systems. [[Mussels]] and [[kelp]] growing adjacent to [[Atlantic salmon]] cages in the Bay of Fundy have been monitored since 2001 for contamination by medicines, [[Heavy metal (chemistry)|heavy metals]], [[arsenic]], [[Polychlorinated biphenyl|PCBs]] and [[pesticide]]s. Concentrations are consistently either non-detectable or well below regulatory limits established by the [[Canadian Food Inspection Agency]], the United States [[Food and Drug Administration]] and [[European Community]] Directives.<ref name="Haya et al. 2004">Haya K, Sephton D, Martin J and Chopin T. 2004. Monitoring of therapeutants and phycotoxins in kelps and mussels co-cultured with Atlantic salmon in an integrated multi-trophic aquaculture system. Bulletin of the Aquaculture Association of Canada. 104(3): 29-34.</ref><ref name="Chopin et al. 2007">Chopin T, Sawhney M, Shea R, Belyea E, Bastarache S, Armstrong W, Reid GK, Robinson SMC, MacDonald B, Haya K, Burridge L, Page F, Ridler N, Justason A, Sewuster J, Powell F and Marvin R. 2007. An interdisciplinary approach to the development of integrated multi-trophic aquaculture (IMTA): the inorganic extractive component. World Aquaculture Society. Aquaculture 2007 conference proceedings, pg. 177. (https://www.was.org/Meetings/AbstractData.asp?AbstractId=13724 {{Webarchive|url=https://web.archive.org/web/20070927003926/https://www.was.org/Meetings/AbstractData.asp?AbstractId=13724 |date=2007-09-27 }})</ref> Taste testers indicate that these mussels are free of "fishy" taste and aroma and could not distinguish them from "wild" mussels. The mussels'  meat yield is significantly higher, reflecting the increase in nutrient availability.<ref name="Lander et al. 2004"/>
Recent findings suggest mussels grown adjacent to salmon farms are advantageous for winter harvest because they maintain high meat weight and condition index (meat to shell ratio). This finding is of particular interest because the Bay of Fundy, where this research was conducted, produces low condition index mussels during winter months in monoculture situations, and seasonal presence of [[paralytic shellfish poisoning]] (PSP) typically restricts mussel harvest to the winter months.<ref>{{cite journal|last=Lander|first=Terralynn R.|author2=Shawn M. C. Robinson, Bruce A. MacDonald and James D. Martin|title=Enhanced Growth Rates and Condition Index of Blue Mussels (Mytilus edulis) Held at Integrated Multitrophic Aquaculture Sites in the Bay of Fundy|journal=Journal of Shellfish Aquaculture|date=December 2012|volume=31|series=4|issue=4|pages=997–1007|doi=10.2983/035.031.0412|s2cid=86663479}}</ref>

==Selected projects==
{{Farming}}

Historic and ongoing research projects include:

===Asia===
Japan, China, South Korea, Thailand, Vietnam, Indonesia, Bangladesh, etc. have co-cultured aquatic species for centuries in marine, [[brackish]] and fresh water environments.<ref name="Chopin et al. 2001"/><ref name="Neori et al. 2004"/> Fish, shellfish and seaweeds have been cultured together in [[bay]]s, [[lagoons]] and ponds. Trial and error has improved integration over time.<ref name="Neori et al. 2004"/> The proportion of Asian aquaculture production that occurs in IMTA systems is unknown.

After the 2004 tsunami, many of the shrimp farmers in Aceh Province of Indonesia and Ranong Province of Thailand were trained in IMTA.  This has been especially important as the mono-culture of marine shrimp was widely recognized as unsustainable.  Production of tilapia, mud crabs, seaweeds, milkfish, and mussels have been incorporated.   [http://aquafishcrsp.oregonstate.edu/index.php AquaFish Collaborative Research Support Program]

=== Canada ===

==== Bay of Fundy ====
Industry, academia and government are collaborating here to expand production to commercial scale.<ref name="Chopin 2006"/> The current system integrates [[Atlantic salmon]], [[blue mussel]]s and [[kelp]]; deposit feeders are under consideration. AquaNet (one of [[Canada]]'s Networks of Centres of Excellence) funded phase one. The [[Atlantic Canada]] Opportunities Agency is funding phase two. The project leaders are [[Thierry Chopin]] ([[University of New Brunswick]] in [[Saint John, New Brunswick|Saint John]]) and Shawn Robinson ([[Department of Fisheries and Oceans]], [[St. Andrews Biological Station]]).<ref name="Chopin et al. 2004"/><ref name="Chopin et al. 2007"/><ref name="Robinson et al. (2007)">Robinson SMC, Lander T, Martin JD, Bennett A, Barrington K, Reid GK, Blair T, Chopin T, MacDonald B, Haya K, Burridge L, Page F, Ridler N, Justason N, Sewuster J, Powell F and Marvin R. 2007. An interdisciplinary approach to the development of integrated multi-trophic aquaculture (IMTA): the organic extractive component. World Aquaculture Society. Aquaculture 2007 conference proceedings, pg.786. (https://www.was.org/Meetings/AbstractData.asp?AbstractId=13764 {{Webarchive|url=https://web.archive.org/web/20120513021339/https://www.was.org/Meetings/AbstractData.asp?AbstractId=13764 |date=2012-05-13 }})</ref>

==== Pacific SEA-lab ====
Pacific SEA-lab is researching and is licensed for the co-culture of [[sablefish]], [[scallops]], oysters, blue mussels, [[Sea urchin|urchin]]s and kelp. "SEA" stands for Sustainable Ecological Aquaculture. The project aims to balance four species.<!--which four?--> The project is headed by Stephen Cross under a [[British Columbia]] Innovation Award at the [[University of Victoria]] Coastal Aquaculture Research & Training (CART) network.<ref name="Cross (2007)">Cross S. 2007. Making the case: quantifying the benefits of integrated multi-trophic aquaculture (IMTA). World Aquaculture Society. Aquaculture 2007 conference proceedings, pg. 209. (https://www.was.org/Meetings/AbstractData.asp?AbstractId=14507 {{Webarchive|url=https://web.archive.org/web/20070927003428/https://www.was.org/Meetings/AbstractData.asp?AbstractId=14507 |date=2007-09-27 }})</ref>

===Chile===
The i-mar Research Center<ref>{{cite web|url=http://www.i-mar.cl|title=i-mar Research Center}}</ref> at the [[Universidad de Los Lagos]], in [[Puerto Montt, Chile|Puerto Montt]] is working to reduce the environmental impact of intensive salmon culture. Initial research involved trout, oysters and seaweeds. Present research is focusing on open waters with salmon, seaweeds and abalone. The project leader is Alejandro Buschmann.<ref name="Buschmann et al. (2007)">Buschmann AH, Varela DA, Hernández-González MC, Henríquez L, Correa J, Flores R and Gutierrez A. 2007. The development of an integrated multi-trophic activity in Chile: the importance of seaweeds. World Aquaculture Society. Aquaculture 2007 conference proceedings, pg. 136. (https://www.was.org/Meetings/AbstractData.asp?AbstractId=14199 {{Webarchive|url=https://web.archive.org/web/20070927003858/https://www.was.org/Meetings/AbstractData.asp?AbstractId=14199 |date=2007-09-27 }})</ref>

===Israel===

====SeaOr Marine Enterprises Ltd.====
SeaOr Marine Enterprises Ltd., which operated for several years on the [[Israel]]i [[Mediterranean coast]], north of [[Tel Aviv]], cultured marine fish ([[gilthead seabream]]), seaweeds (Ulva and Gracilaria) and Japanese [[abalone]]. Its approach leveraged local climate and recycled fish waste products into seaweed biomass, which was fed to the abalone. It also effectively purified the water sufficiently to allow the water to be recycled to the fishponds and to meet point-source effluent environmental regulations.

====PGP Ltd.====
PGP Ltd. is a small farm in Southern Israel. It cultures marine fish, microalgae, bivalves and [[Artemia]]. Effluents from seabream and seabass collect in [[sedimentation]] ponds, where dense populations of microalgae&mdash;mostly [[diatom]]s&mdash;develop. [[Clam]]s, oysters and sometimes Artemia filter the microalgae from the water, producing a clear effluent. The farm sells the fish, bivalves and Artemia.

===The Netherlands===
In the Netherlands, Willem Brandenburg of UR Wageningen (Plant Sciences Group) has established the first seaweed farm in the Netherlands. The farm is called "De Wierderij" and is used for research.<ref>{{cite web|url=http://www.ztrdg.nl/2011/09/vrienden/helden/willem-brandenburg-is-held-van-ztrdg/|title=De Wierderij|url-status=dead|archive-url=https://web.archive.org/web/20120730151548/http://www.ztrdg.nl/2011/09/vrienden/helden/willem-brandenburg-is-held-van-ztrdg/|archive-date=2012-07-30}}</ref>

===South Africa===
Three farms grow seaweeds for feed in abalone effluents in land-based tanks. Up to 50% of re-circulated water passes through the seaweed tanks.<ref name="Bolton et al. 2006">Bolton J, Robertson-Andersson DM, Troell M, and Halling C. 2006. Integrated system incorporates seaweeds in South African abalone culture. Global Aquaculture Advocate, Vol. 9, No. 4, July/August 2006, pg. 54-55.</ref> Somewhat uniquely, neither fish nor shrimp comprise the upper trophic species. The motivation is to avoid over-harvesting natural seaweed beds and red tides, rather than nutrient abatement<!--what does this mean? ->", by turning the system in the recirculation mode"-->. These commercial successes developed from research collaboration between Irvine and Johnson Cape Abalone and scientists from the [[University of Cape Town]] and the [[Stockholm University]].<ref name="Bolton et al. 2006"/>

===United Kingdom===
[[The Scottish Association for Marine Science]], in [[Oban, Scotland|Oban]] is developing co-cultures of salmon, oysters, sea urchins, and brown and red seaweeds via several projects.<ref>{{cite web|url=http://www.sams.ac.uk/research/departments/ecology/ecology-projects/integrated-aquaculture/researchproject.2007-06-05.2431610615/view|title=MERMAIDS|access-date=2007-10-03|archive-url=https://web.archive.org/web/20080604203644/http://www.sams.ac.uk/research/departments/ecology/ecology-projects/integrated-aquaculture/researchproject.2007-06-05.2431610615/view|archive-date=2008-06-04|url-status=dead}}</ref><ref>{{cite web|url=http://www.sams.ac.uk/research/departments/ecology/ecology-projects/integrated-aquaculture/researchproject.2007-04-19.3044544946?searchterm=aaag|title=AAAG|access-date=2007-10-03|archive-url=https://web.archive.org/web/20080604203639/http://www.sams.ac.uk/research/departments/ecology/ecology-projects/integrated-aquaculture/researchproject.2007-04-19.3044544946?searchterm=aaag|archive-date=2008-06-04|url-status=dead}}</ref><ref>{{cite web|url=http://www.sams.ac.uk/research/departments/ecology/ecology-projects/integrated-aquaculture/researchproject.2007-06-05.6589098528?searchterm=redweed|title=REDWEEDS|access-date=2007-10-03|archive-url=https://web.archive.org/web/20080604203649/http://www.sams.ac.uk/research/departments/ecology/ecology-projects/integrated-aquaculture/researchproject.2007-06-05.6589098528?searchterm=redweed|archive-date=2008-06-04|url-status=dead}}</ref><ref>{{cite web|url=http://www.sams.ac.uk/research/departments/ecology/ecology-projects/integrated-aquaculture/researchproject.2007-04-23.9237834111|title=SPIINES2|access-date=2007-10-03|archive-url=https://web.archive.org/web/20080517071116/http://www.sams.ac.uk/research/departments/ecology/ecology-projects/integrated-aquaculture/researchproject.2007-04-23.9237834111|archive-date=2008-05-17|url-status=dead}}</ref> Research focuses on biological and physical processes, as well as production economics and implications for coastal zone management. Researchers include: M. Kelly, A. Rodger, L. Cook, S. Dworjanyn, and C. Sanderson.<ref name="Kelly et al. (2007)">Kelly MS, Sanderson C, Cook EJ, Rodger A and Dworjanyn SA. 2007. Integration: enhancing sustainability in open water aquaculture systems. World Aquaculture Society. Aquaculture 2007 conference proceedings, pg. 458. (https://www.was.org/Meetings/AbstractData.asp?AbstractId=14295 {{Webarchive|url=https://web.archive.org/web/20070927003435/https://www.was.org/Meetings/AbstractData.asp?AbstractId=14295 |date=2007-09-27 }})</ref><ref name="Rodger et al. (2007)">Rodger A, Cromey C and Kelly M. 2007. Open water integrated aquaculture - use of depositional modelling to assist finfish/bivalve integration, for growth optimisation and prediction of waste dispersal. World Aquaculture Society. Aquaculture 2007 conference proceedings, pg. 788. (https://www.was.org/Meetings/AbstractData.asp?AbstractId=14213 {{Webarchive|url=https://web.archive.org/web/20070927003905/https://www.was.org/Meetings/AbstractData.asp?AbstractId=14213 |date=2007-09-27 }})</ref>

===Bangladesh===
[[File:IMTA in Freshwater Pond.JPG|thumb|IMTA systems in freshwater pond]]

[[Catla catla|Indian carps]] and [[Heteropneustes fossilis|stinging catfish]] are cultured in Bangladesh, but the methods could be more productive. The pond and cage cultures used are based only on the fish. They don't take advantage of the productivity increases that could take place if other trophic levels were included. Expensive artificial feeds are used, partly to supply the fish with protein. These costs could be reduced if freshwater snails, such as ''Viviparus bengalensis'', were simultaneously cultured, thus increasing the available protein. The organic and inorganic wastes produced as a byproduct of culturing could also be minimized by integrating freshwater snail and aquatic plants, such as [[water spinach]], respectively.<ref>{{cite web|last=Television|first=Diganta|title=Integrated Multi-Trophinc Aquaculture (IMTA) Bangladesh|url=https://www.youtube.com/watch?v=zRMmiDauvs4 |archive-url=https://ghostarchive.org/varchive/youtube/20211221/zRMmiDauvs4 |archive-date=2021-12-21 |url-status=live|publisher=Diganta Television Bangladesh}}{{cbignore}}</ref>

==Gallery==
<gallery>
File:Carp (Catla catla) produced in IMTA pond.JPG|Carp (Labeo rohita) produced in IMTA pond
File:Off-bottom snail grown on bamboo split in IMTA.JPG|Off-bottom snail grown on bamboo split in IMTA
File:Snail produced on pond bottom of IMTA.JPG|Snail produced on pond bottom of IMTA
File:IMTA in Bangladsh.jpg|Collection of water spinach and snail from IMTA pond
File:Produced shing in cage in IMTA.JPG|Produced shing in cage in IMTA
</gallery>

== See also ==
{{div col|colwidth=22em}}
*[[Agribusiness]]
*[[Extensive farming]]
*[[Factory farming]]
*[[Genetically modified organism]]
*[[History of agriculture]]
*[[Industrial agriculture]]
*[[Industrial agriculture (animals)]]
*[[Industrial agriculture (crops)]]
*[[Intensive farming]]
*[[Organic farming]]
*[[Sustainable agriculture]]
*[[Zero waste agriculture]]
{{div col end}}

==Notes==
{{reflist|33em}}

==References==
* Neori A, Troell M, Chopin T, Yarish C, Critchley A and Buschmann AH. 2007. The need for a balanced ecosystem approach to blue revolution aquaculture. Environment 49(3): 36–43.

== External links ==
*[http://www.aquanet.ca/English/innovate/index.php AquaNet IMTA] {{Webarchive|url=https://web.archive.org/web/20070729014040/http://www.aquanet.ca/English/innovate/index.php |date=2007-07-29 }}
*[http://www.sams.ac.uk/ www.sams.ac.uk]
*[https://web.archive.org/web/20070927003947/https://www.was.org/Meetings/SessionAbstracts.asp?MeetingCode=AQ2007&Session=64 World Aquaculture Conference 2007: IMTA session]
*[https://web.archive.org/web/20070904023739/http://www.unbsj.ca/sase/biology/chopinlab/ Chopin lab]
*[https://www.springer.com/east/home/life+sci/ecology?SGWID=5-10034-22-35293458-detailsPage=ppmmedia|toc The Comparative Roles of Suspension-Feeders in Ecosystems] The use of bivalves as biofilters and valuable product in land based aquaculture systems - review.
*[https://web.archive.org/web/20060927201503/http://www.eti.uva.nl/products/catalogue/cd_detail.php?referrer=latest&id=214 Seaweed Resources of the World] Algae: key for sustainable mariculture.
*[https://www.springer.com/west/home/life+sci/ecology?SGWID=4-10034-22-173734694-detailsPage=ppmmedia|toc Ecological and Genetic Implications of Aquaculture Activities] Evaluation of macroalgae, microalgae, and bivalves as biofilters in sustainable land-based mariculture systems.
{{fishing industry topics|expanded=aquaculture}}
{{fisheries and fishing}}

{{Commonscat|Integrated multi-trophic aquaculture}}
[[Category:Hydrography]]
[[Category:Physical oceanography]]
[[Category:Aquaculture]]