gain experience before considering intensification as it is relatively low cost with minimal risk and may be considered as the “first step on the ladder of intensification” (Edwards, 2009b).

## 6.2. Modern aquaculture

A recent and accelerating trend in Asian aquaculture is a decline in the share of most IAA to the total production, with delinking integrated fish, crop and/or livestock subsystems or enterprises. Intensification is taking place through increased use of formulated feed and specialization or monoculture. So called “modern” aquaculture has a higher cost of investment but produces more profit than traditional IAA although at greater risk. A primary driver of intensification in Asia is the desire of households, including small-scale farming households that dominate Asian aquaculture in terms of number of farms if not in total production, to improve their livelihoods and increase income. Small-scale farming households are usually multi-generational and generally have diverse livelihood portfolios (Rigg, 2006); they compare the income generation of various options both on- and off-farm, including that of aquaculture which would likely need to be financially attractive to be sustainable.

However, agroecology does have a role to play in the future development of aquaculture. The principles of agroecology are still highly relevant to manage the transitions to more adaptive, efficient and resilient integrated systems (Halwart, Dabbadie and Beveridge, 2019). There are traditional IAA which thrive today as well new systems that deserve a more thorough assessment. Perhaps the best example is the farming a red coloured variety of common carp in stream-fed terraced rice fields in mountainous Qingtian County, Zhejiang Province, China that has a documented history of 1 200 years (Edwards, 2006; Lu and Li, 2006; Hu et al., 2016; Ren et al., 2018). The fish have a high market value because of their special taste with local households and restaurants involved in ecotourism (FAO, 2016). The system has been listed by FAO, UNDP and GEF as a ‘globally important indigenous agriculture heritage system’. While more widespread dissemination of the system appears unlikely because of its special situation as a localized tourist site, more recently developed integrated culture of high value crustaceans in well-watered rice fields in Bangladesh, China and Viet Nam as outlined above has potential for considerable expansion.

Some of the principles of traditional IAA practice could be used to make ‘modern’ aquaculture more environmentally friendly as well as to reduce production costs (Edwards, 2014b, 2015). Examples are:

* nutrient and water reuse with intensive aquaculture effluents used for crop irrigation and aquaponics;

* Chinese polyculture with 80 percent pellet-fed fish integrated with 20 percent filter feeding fish;

* pellet-fed caged fish integrated in a pond in which fingerlings are nursed on ‘green water’ produced from caged-fish fish wastes;

* reduction of feed costs, especially in nursing and early grow-out when fish are small, by using ‘green water’ rather than formulated feed; and,

* biofloc systems in which feed costs are reduced and the water quality improved by the production of protein-rich natural food from the addition of low-cost carbohydrate-rich supplementary feed to N-rich fish wastes which otherwise would require treatment.

## 7. Acknowledgement

Dr Wenbo Zhang provided thorough and helpful comments on an early version of this manuscript.
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# AGROECOLOGY AND ITS APPLICATION TO AQUACULTURE

Malcolm Beveridge and Lionel Dabbadie

## 1. Introduction

With world hunger rising again after decades of decrease since the 1990s, there are growing concerns that the increasingly dominant high-input, resource-intensive model of food production has created massive problems of deforestation, water scar cities, soil depletion, greenhouse gas emission and biodiversity loss and cannot deliver sustainable food or agriculture production (FAO, 2017). Critical parts of our food systems are becoming ever more capital-intensive, vertically integrated and concentrated in fewer hands. It is argued that what is required is nothing short of a transformation towards a more holistic approach to food production and its governance.

The term ‘agroecology’ was first used in the 1920s to refer to “... *the application of ecology to agriculture*”.<fnref n="13" /> Half-a-century later McKay (1983) coined the term “ecological aquaculture”, which he defined as “... *the application of ecological principles to aquaculture*”. This is synonymous with the original definition of agroecology, further refined a few years later by Alteri (1995) (“... *the application of ecological concepts and principles to the design and management of sustainable agroecosystems*”). In his Preface to the multi-authored volume on ecological aquaculture produced at the beginning of the 21st century Costa-Pierce (2002) elaborated ecological aquaculture as “... *a model that uses ecological principles and ecosystems thinking as the fundamental organizing paradigm for the development of aquaculture*”, closely paralleling the prevailing view of agroecology at the beginning of the present century.

Interest in agroecology grows apace, its original focus extending in scale from the plot and farm level to entire food production systems, and attracting interest from stakeholders across the social, economic and natural sciences as well as from policy makers (Wezel *et al.*, 2009). The diversity of interpretations is captured by FAO in a database of some 20 definitions and in the organisation's current working definition:

> "Agroecology is based on applying ecological concepts and principles to optimize interactions between plants, animals, humans and the environment while taking into consideration the social aspects that need to be addressed for a sustainable and fair food system. By building synergies, agroecology can support food production and food security and nutrition while restoring the ecosystem services and biodiversity that are essential for sustainable agriculture. Agroecology can play an important role in building resilience and adapting to climate change".

The concept encompasses many not entirely consistent visions. Baatard *et al.* (2013) propose a grid highlighting the areas in which different current concepts of agroecology differ. It can be with regard to the challenges assigned to agroecology by their promoters, to the knowledge, concepts and disciplines mobilized, to the thematic and spatio-temporal scope of the system considered, to the principles and levers of action used, to the agroecology stakeholders put forward, to the possible reference to ethics or to the sources of inspiration and geographical anchoring. FAO has focused on the common ground shared by the various proponents, to formulate 10 interdependent agroecology elements (Table 1) in order to operationalize an agroecological approach among member countries to create large-scale transformation of food and agricultural systems to achieve Zero Hunger and other Sustainable Development Goals (SDGs).

Our Introduction provides context and complements a series of case study-based presentations on agroecology and aquaculture. We consider how an agroecological approach is being - and could further be - applied to aquaculture and how novel aquaculture technologies offer potential solutions to

<footnote n="13">¹³ See the FAO database on agroecology www.fao.org/agroecology/knowledge/definitions</footnote>
sustainability issues in aquaculture. We begin by briefly considering the key issues around aquaculture and sustainability.

## 2. Aquaculture and sustainability issues

Aquaculture production has grown rapidly in recent decades and since 2014 has supplied the majority of fish consumed by humans in the world (FAO, 2018a). The prevailing discourse is that for the foreseeable future aquaculture will be the primary source of increases in aquatic food supplies needed to meet the demands of a growing and increasingly wealthy human population (FAO, *ibid*). However, there have also long been concerns about the environmental and social impacts of the sector (Beveridge, Ross and Kelly, 1994, Naylor *et al.*, 2001; Béné *et al.*, 2016). Accompanying increases in production, for example, has been an intensification of production methods, including an increasing reliance on commercial, pelleted feeds that utilise scarce fishmeal and fish oil resources (Tacon *et al.*, 2013; Little *et al.*, 2016; FAO, 2018a) and increases in the prevalence of aquatic disease (Subasinghe *et al.*, 2001). Conflicts have arisen between aquaculture and other sectors, particularly over competition for space in coastal areas, in the use of agricultural land (Aguilar-Manjarrez *et al.*, 2017) and fresh water, especially in relation to aquaculture feed production (Gephart *et al.*, 2017). There are concerns about the sustainable use of aquatic genetic resources for aquaculture (FAO, 2019). Climate change is also likely to adversely impact on future aquaculture production (Dabbadie *et al.*, 2018), further fuelling concerns about the sustainability of the sector, its abilities to meet the anticipated gap between demand and supply of aquatic foods and its impacts on climate change and the environment.

## 3. Aquaculture and agroecology

Ecological aquaculture initially drew heavily on systems ecology, which emerged in the late 1960s and 1970s (see Odum, 1983), and the pioneering work on development of aquaculture at the New Alchemy Institute, Massachusetts, United States of America,<fnref n="14" /> which combined systems ecology thinking with technologies new and old in order to develop production systems that both relied on and conserved ecosystem services. Pioneers found much to emulate in the traditional types of integrated aquaculture still being practiced in Asia (e.g. rice-fish culture, waste fed aquaculture; see, for example, Little and Muir, 1983; Edwards, Demaine and Little, 2002). More recently, agroecological elements have both been applied to conventional aquaculture (e.g. stocking lumpfish (*Cyclopterus lumpus*) or wrasse [Labridae] in Atlantic salmon (*Salmo salar*) cages to control sea lice and replace use of pesticides; Powell, *et al.*, 2017). New technologies, fully rooted in agroecology, have also emerged including recirculation aquaculture systems (RAS; e.g. Badiola *et al.*, 2018), aquaponics (Sommerville *et al.*, 2014), periphyton-based aquaculture (Dabbadie, 1996; Azim *et al.*, 2005; Figure 1) and Integrated Multi-Trophic Aquaculture (IMTA; e.g. Granada *et al.*, 2016).

<footnote n="14">¹⁴ See, for example: [newalchemists.files.wordpress.com/2015/01/solar-aquaculture-primer-by-eab1.pdf](https://newalchemists.files.wordpress.com/2015/01/solar-aquaculture-primer-by-eab1.pdf)</footnote>
<figure><img src="image_25.png" /></figure>

**Figure 1:** Example of periphyton-based aquaculture pond with integrated chicken farming experimented in Côte d'Ivoire in 1993 by using bamboo sticks.

FAO's ten interdependent agroecological elements are shown in Table 1 and demonstrate the wide applicability of the approach to aquaculture.

**4. Discussion**

Agroecology has an increasingly strong theoretical base, encompassing not just production but entire food systems, with implementation being driven by empirical evidence from scientific, on-farm trials and feedback from participatory stakeholder workshops. However, it is one of several emerging approaches to counter the prevailing model by which the USD 5 trillion global food system operates. Others include conservation agriculture, organic agriculture, permaculture and climate smart agriculture. Baatard *et al.* (2013) propose a comparison of these approaches and how they differentiate from - and might also strengthen and coexist with - agroecology. All aim to develop sustainable food systems that produce nutritious foods that meet the needs of consumers, that value culture and small-scale farms and that generate equitable benefits throughout value chains. However, some are based on primarily on principles that should be respected (e.g. agroecology) whilst others focus on meeting certain objectives (e.g. climate-smart agriculture).

While critics maintain that such approaches, while perhaps worthy, won't feed the world a recent Opinion Piece in the New York Times reports on a number of large-scale on-going investments as evidence that agroecology is becoming mainstream.<fnref n="15" /> This includes investments of USD 2.3 billion of public funds in Andra Pradesh, India, over the next five years to convert six million farmers to “zero-budget natural farming” (farming that does not rely on credit or purchased inputs) and USD 1 billion to French farmers to adopt agroecology by 2025.

As summarised in Table 1, all of the FAO elements of agroecology are applicable to aquaculture and that aquaculture can be incorporated into many agriculture systems to help strengthen agroecological elements. But how prevalent is agroecology in aquaculture? It is difficult to say but probably the majority of aquaculture production addresses at least some elements, although little of present-day production subscribes to more than a handful. As highlighted by Edwards (elsewhere, this volume) traditional types of aquaculture, practiced in Asia for centuries, embodied many of the agroecology elements that FAO promotes. However, prevailing economic drivers – rising costs of land and labour, affordability of feed,

<footnote n="15">¹⁵ The full article is available at www.nytimes.com/2018/06/26/opinion/farming-organic-nature-movement.html</footnote>
cheap energy - have been steering farmers towards aquaculture monocultures and intensive production methods to increase profits per unit land use.

While there is no doubt that the application of agroecological elements in aquaculture can improve sustainability, a number of issues must be addressed if it is to be mainstreamed in the sector. Foremost is the question of whether agroecological practices can be readily adopted without compromising on profits. There needs to be the kind of concerted effort seen in agroecology to implement coordinated, large-scale and scientifically robust trials to determine impacts of agroecological practices on key sustainability indicators. Stakeholders must assume ownership of the process to ensure that technologies meet their needs, that there is an equitable sharing of risks and benefits throughout value chains, and to ensure rapid and sustained uptake of innovations. Agroecological aquaculture must also prove attractive to youth, increasingly disenfranchised from much of present-day food production (FAO, 2014). Novel, more technological approaches to aquaculture, such as RAS, periphyton-based aquaculture, aquaponics, IMTA, integrated mangrove-shrimp culture, may prove more attractive to youth. Finally, environmental services need to be fully costed in food production systems and the system of subsidies changed to reflect this. Only then will policy makers consider changing policies and governance to promote an agroecological approach.

Aquaculture practitioners often view the world from an aquaculture-centric perspective. However, governments, whose primary mandate is to ensure the health and welfare of its people, must take a broader perspective. Growing awareness of the potential of the Blue Economy and Blue Growth (FAO, 2018c) to provide a range of economic, social and environmental benefits is beginning to influence the development of coherent policies across sectors and may help foster an enabling environment for agroecological approaches to aquaculture. For example, in Ireland farmed Atlantic salmon production has fallen substantially in recent decades. The national strategic plan for sustainable aquaculture has ambitions to grow cage farming of Atlantic salmon, but rather than trying to compete on price with much larger producing countries, it is being encouraged to conform to the country's ambitions to be one of the most important producers of high quality, organic foods in the European Union and complement tourism.<fnref n="16" /> It thus seeks to encourage the development of small, sensitively sited, family-owned organic salmon farming and seafood processing businesses, embodying many of the principles of agroecology. Tourists undertaking the Wild Atlantic Way are encouraged to engage with artisanal aquaculture producers – seaweed, oysters, mussels and salmon – as part of the experience.<fnref n="17" /> Other European Union national aquaculture plans show similar integration within a Blue Economy framework and include agroecological elements.

Guidance is required to support policy makers in developing the aquaculture sector in their countries. The Ecosystem Approach to Aquaculture (EAA), developed in 2008 to promote ‘...integration of aquaculture within the wider ecosystem such that it promotes sustainable development, equity, and resilience of interlinked social-ecological systems’ (FAO, 2010; Brugère et al., 2018), provides a highly relevant framework on which to build cohesive guidance on an agroecological approach to aquaculture.

## 5. References

* Aguilar-Manjarrez, J., Soto, D. & Brummett, R. 2017. *Aquaculture zoning, site selection and area management under the ecosystem approach to aquaculture*. A handbook. Report ACS18071. Rome, FAO, and World Bank Group, Washington, DC. 62 pp.

* Altieri, M. 1995. *Agroecology: The Scientific Basis of Alternative Agriculture*. West View Press, Boulder.

<footnote n="16">¹⁶ For more information
[www.agriculture.gov.ie/media/migration/seafood/marineagenciesandprogrammes/nspa/NationalStrategicPlanSusAquaDevel181215.pdf](http://www.agriculture.gov.ie/media/migration/seafood/marineagenciesandprogrammes/nspa/NationalStrategicPlanSusAquaDevel181215.pdf)</footnote>

<footnote n="17">¹⁷ For more information: [www.ireland.com/en-gb/](http://www.ireland.com/en-gb/)</footnote>
Azim, M. E., Verdegem, M. C. J., van Dam, A. A. & Beveridge, M. C. M., eds. 2005. *Periphyton: Ecology, Exploitation and Management*. CAB International, Cambridge, pp. 319.

Baatard, B., Carof, M., Clermont-Dauphin, C., Doré, T., Fitoussi, G., Gardarin, A., Herry, C. & Sarthou J.P. 2013. *Qu'est-ce que l'agro-écologie ?* E-learning module, Université Virtuelle d'AgroÉcologie. www.ea.inra.fr/uvae

Badiola, M., Basurko, O. C., Piedrahita, R., Hundley, P. & Mendiola, D. 2018. Energy use in Recirculating Aquaculture Systems (RAS): A review. *Aquacultural Engineering* **81**: 51-70.

Béné, C., Arthur, R., Norbury, H., Allison, E. A., Beveridge, M., Bush, S., Campling, L., Leschen, W., Little, D. C., Squires, D., Thilsted, S. H., Troell, M. and Williams, M. 2016. Contribution of fisheries and aquaculture to food security and poverty reduction: assessing the current evidence. *World Development* **77**, 179-196.

Beveridge, M. C. M., Ross, L. G. and Kelly, L. A. 1994. Aquaculture and biodiversity. *Ambio*, **23**, 497-502.

Brugère C., Aguilar-Manjarrez J., Beveridge, M. C. M. & Soto, D. 2018. The Ecosystem Approach to Aquaculture 10 years on – a critical review and consideration of its future role in Blue Growth. *Reviews in Aquaculture* **9**, DOI: 10.1111/raq.12242.

Costa-Pierce, B.A., ed. 2008. *Ecological Aquaculture: The Evolution of the Blue Revolution*. Blackwell, Oxford.

Dabbadie, L. 1996. *Étude de la viabilité d'une pisciculture rurale à faible niveau d'intrant dans le Centre-Ouest de la Côte d'Ivoire: approche du réseau trophique*. Thèse doctorat, Université Pierre et Marie Curie, Paris 6, France: 208 p. agritrop.cirad.fr/300407/1/ID300407.pdf

Dabbadie, L., Aguilar-Manjarrez, J., Beveridge, M.C.M., Bueno, P.B., Ross, L.G. & Soto, D. 2018. Effects of climate change on aquaculture: drivers, impacts and policies. In M. Barange, T. Bahri, M. Beveridge, K. Cochrane, S. Funge-Smith and F. Poulain (Eds.). 2018. *Impacts of Climate Change on Fisheries and Aquaculture: Synthesis of Current Knowledge, Adaptation and Mitigation Options*. FAO Fisheries Technical Paper **627**, pp. 451-465. www.fao.org/3/i9705en/i9705en.pdf

Edwards, P., Demaine, H. & Little, D. C. 2002. *Rural aquaculture*. Cambridge, CABI.

FAO. 2010. *Aquaculture Development. 4. Ecosystem Approach to Aquaculture*. FAO Technical Guidelines for Responsible Fisheries. No. 5, Suppl. 4. FAO, Rome. www.fao.org/docrep/013/i1750e/i1750e00.htm.

FAO. 2014. *Youth and Agriculture. Key Challenges and Concrete Solutions*. Rome, FAO. pp. 105. www.fao.org/3/a-i3947e.pdf.

FAO. 2017. *The future of food and agriculture – Trends and challenges*. FAO, Rome. www.fao.org/publications/fofa/en/

FAO. 2018a. *State of the world fisheries and aquaculture*. FAO, Rome. www.fao.org/documents/card/en/c/I9540EN/

FAO. 2019. *State of the World's Aquatic Genetic Resources for Food and Agriculture*. Rome, FAO. www.fao.org/3/CA5256EN/CA5256EN.pdf

FAO. 2018c. *Achieving Blue Growth. Building vibrant fisheries and aquaculture communities*. Rome, FAO. www.fao.org/3/CA0268EN/ca0268en.pdf

Gephart, J.A., Troell, M., Henriksson, P., Beveridge, M.C.M., Verdegem, M., Metian, M., Mateos, L.D. & Deutsch, L. 2017. The ‘seafood-gap’ in the food-water nexus literature – issues surrounding freshwater use in seafood production chains. *Advances in Water Resources*, 110: 505–514. dx.doi.org/10.1016/j.advwatres.2017.03.025.
Granada, L., Sousa, N., Lopes, S. & Lemos, M. F. L. 2016. Is integrated multitrophic aquaculture the solution to the sectors' major challenges? – a review. *Reviews in Aquaculture* 8: 283-300.

Little, D. C. & Muir, J. F. 1987. *A Guide to Integrated Warmwater Aquaculture*. Scotland, United Kingdom. University of Stirling. pp. 325.

Little, D. C., Newton, R. W. & Beveridge, M.C.M. 2016. Aquaculture: a rapidly growing and significant source of sustainable food? *Status, transitions and potential. Proceedings of the Nutrition Society* 75: 274-286. (also available at doi.org/10.1017/S0029665116000665).

McKay, K. 1983. Ecological aquaculture, new approaches to aquaculture in North America. *Journal of the World Mariculture Society* 14, 704-713.

Naylor R L, Goldburg R J, Mooney H, Beveridge M C M, Clay J, Folke C, Kautsky N, Lubchenko J, Primavera J & Williams M. 1998. Nature's subsidies to shrimp and salmon farming. *Science* 282, 883-884.

Odum, H. T. 1983. *Systems Ecology: An Introduction*. New York, John Wiley and Sons.

Powell, A., Treasurer, J. W., Pooley, C. L., Keay, A. J., Lloyd, R., Imsland, K. R. & Garcia de Leanis, C. 2017. Use of lumpfish for sea-lice control in salmon farming: challenges and opportunities. *Reviews in Aquaculture* doi.org/

Somerville, C., Cohen, M., Pantanella, E., Stankus, A. & Lovatelli, A. 2014. Small-scale aquaponic food production. Integrated fish and plant farming. FAO Fisheries and Aquaculture Technical Paper 589. Rome, FAO. 262 pp.

Subasinghe, R.P., Bondad-Reantaso, M.G. & McGladdery, S.E. 2001. Aquaculture development, health and wealth. In R.P. Subasinghe, P. Bueno, M.J. Phillips, C. Hough, S.E. McGladdery & J.R. Arthur, eds. *Aquaculture in the Third Millennium*. Technical Proceedings of the Conference on Aquaculture in the Third Millennium, Bangkok, Thailand, 20-25 February 2000. pp. 167-191. NACA, Bangkok and FAO, Rome.

Tacon, A. G. J., Hasan, M. R. & Metian, M. 2011. Demand and Supply of Feed Ingredients for Farmed Fish and Crustceans. *Trends and Prospects*. FAO Fisheries and Aquaculture Technical Paper 564. Rome, FAO. pp. 88.

Wezel, A., Bellon, S., Doré, T., Francis, C., Vallod & David, C. 2009. Agroecology as a science, a movement and a practice. A review. *Agronomy and Sustainable Development* 29: 503-515.
<table><caption>**Table 1:** FAO elements of agroecology and their applicability to aquaculture. Modified from the FAO website on agroecology (www.fao.org/agroecology/knowledge/10-elements/en/)</caption><thead><tr><td>Elements</td><td>Description</td><td>Applicability to aquaculture</td></tr></thead><tbody><tr><td>Diversity</td><td>Diversification is key to agroecological transitions to ensure food security and nutrition while conserving, protecting and enhancing natural resources</td><td>Diversification of on-farm agriculture production by culturing fish, such as tilapias, carps, and catfish, freshwater giant prawn, molluscs, aquatic plants. Applicable farm to landscape scale.</td></tr><tr><td>Co-creation and sharing of knowledge</td><td>Agricultural innovations respond better to local challenges when they are co-created through participatory processes</td><td>Highly applicable. Co-development and sharing of aquaculture technologies that meet the needs of farmers, communities and wider society.</td></tr><tr><td>Synergies</td><td>Building synergies enhances key functions across food systems, supporting production and multiple ecosystem services</td><td>Aquaculture can be designed to generate (e.g. provision of nutrients) and enhance ecosystem services (e.g. provision of water in farm ponds) as well as consume them.</td></tr><tr><td>Efficiency</td><td>Innovative agroecological practices produce more using less external resources</td><td>Some types of aquaculture can utilise agricultural wastes (chicken manure, rice bran) as direct/indirect sources of feeds; aquaculture wastewater can be used to grow salad and other crops in aquaponic systems.</td></tr><tr><td>Recycling</td><td>More recycling means agricultural production with lower economic and environmental costs</td><td>Aquaculture can be incorporated into farming systems to utilise wastes from crop and livestock production or to supply nutrient enriched wastewater for irrigation (e.g. desert aquaculture, Egypt)</td></tr><tr><td>Resilience</td><td>Enhanced resilience of people, communities and ecosystems is key to sustainable food and agricultural systems</td><td>Diversification of agriculture systems to include aquaculture can help build resilience of people, communities and ecosystems to external shocks, including climate change.</td></tr><tr><td>Human and social values</td><td>Protecting and improving rural livelihoods, equity and social well-being is essential for sustainable food and agricultural systems</td><td>Development of aquaculture sector strategies and implementation plans should be co-developed with stakeholders, thereby ensuring these elements are comprehensively addressed (e.g. FAO strategic national plans, Africa).</td></tr><tr><td>Culture and food traditions</td><td>By supporting healthy, diversified and culturally appropriate diets, agroecology contributes to food security and nutrition while maintaining the health of ecosystems</td><td>While aquaculture produce can play a role in a healthy and diverse diet, production in any location tends to be reliant on a relatively small number of species, often exotic. However, interventions can and are being made to focus on farming of indigenous species.</td></tr><tr><td>Responsible governance</td><td>Sustainable food and agriculture requires responsible and effective governance mechanisms at different scales – from local to national to global</td><td>The same arguments apply to the sustainable development of aquaculture.</td></tr><tr><td>Circular and solidarity governance</td><td>Circular and solidarity economies that reconnect producers and consumers provide innovative solutions for living within our planetary boundaries while ensuring the social foundation for inclusive and sustainable development</td><td>The same arguments are equally valid in an aquaculture context.</td></tr></tbody></table>
# CURRENT PRACTICES AND FUTURE PROSPECTS FOR INTEGRATED AGRICULTURE AND AQUACULTURE IN ASIA - A REGIONAL REVIEW

Derun Yuan, Peter Edwards, Matthias Halwart

## Abstract

Conventional intensive aquaculture has often been associated with low efficiency of resource utilization and negative environmental impacts. Competition with other food production sectors for water, land and other resources poses the question as whether it can continue to sustain an aquaculture growth rate about 6 percent as it has done in the past three decades. Integrated agriculture and aquaculture (IAA), an old farming practice fast evolving and diversifying in the past three decades, with agroecological approaches that have a number of system merits is expected to be a renewed growth point of aquaculture, to contribute to food security and nutrition for the world growing population in facing resource scarcity, environmental pressure and impacts of climate change. This paper is a general overview of the major IAA systems in several Asian countries today - status, some details of current practices, and development trends. The prospects for future development, including opportunities and constraints are outlined. IAA in Asia displays an amazing diversity in terms of farming activities, system components, operation intensity, and species cultured, and shows potential in increasing productivity and improvement of profitability. Well-configured IAA is able to provide system alternatives to conventional intensive monoculture with possible better ecological efficiency and environmental integrity. IAA continues to be relevant to poverty alleviation, rural nutrition and improvement of farming productivity and probably profitability of resource-poor small-scale farms. IAA should be further researched, fine-tuned, and promoted as an important production strategy for world food supply.

## 1. Introduction

Aquaculture has been growing steadily in the past three decades with an average annual growth rate of about 8 percent from 1985 to 2016 and 5.8 percent from 2001 to 2016.<fnref n="18" /> The global fish production reached 80.0 million tons in 2016, providing over half of the world's fish consumed (FAO, 2018).<fnref n="19" /> In the context of the need to increase food fish production one cannot ignore the contribution that aquaculture *per se* has made to this end.

The continuing increase of production has been fuelled, to a large extent, by the expansion of the pellet-fed intensive aquaculture and an increase of farming area. However, the question has often been asked as to whether intensive aquaculture that requires and competes for limited natural resources such as land and water, can continue to sustain an annual growth rate of 6 percent as it has done in the past two decades. In addition, various intensive forms of aquaculture have been frequently questioned for their ecological efficiency due to inefficient food conversion by often mono-cultured organisms, resulting in waste of otherwise valuable nutrients and causing undesirable environmental impacts at the local and global levels, with the degradation of some important ecosystem services. Competition for natural resources such as land and water has also been a factor that induced social conflicts between users, corrupting social harmony in farming communities.

In the wake of the population growth and increase of fish consumption in human diets, there has been increasing realisation and acknowledgement of the importance of food fish as a source of nutrition and its role in food security at large (Committee on World Food Security, 2014; Béné *et al.*, 2015). There was also an associated call for increasing food fish production to minimise the widening gap between

<footnote n="18">¹⁸ The actual annual growth rates are adjusted with the annual production increments and averaged over the years.</footnote>

<footnote n="19">¹⁹ The amount excludes the production of aquatic mammals, crocodiles, alligators, caimans, seaweeds and other aquatic plants.</footnote>
supply and demand. It is expected that an additional 27 million tonnes of fish will be needed by 2030 (FAO, 2016).

Integrated agriculture-aquaculture (IAA) is a traditional and widespread practice in Asia, with its ecological advantages and social-economic importance. In an IAA farming system, the agriculture and aquaculture components often mutually benefit from each other, and utilize nutrients more efficiently than the agriculture and aquaculture alone with similar resource inputs and operation intensity. The ecological merits of a typical IAA practice may include one or many of the followings:

* biological pest/weed control;

* nutrient resuspension/recycling by aquatic animals benefiting crop production such as the case in rice-fish culture;

* removal and harvest of waste nutrients from aquaculture by plants;

* use of wastes from feedlots/poultry houses as fertilizers to sustain fish growth in semi-intensive aquaculture ponds;

* multiple uses of water and land, better system stability and resilience, and less negative environmental impacts.

Most traditional IAA systems are semi-intensive, demand low intensity of feed/nutrient inputs, and consume no or little unrenewable energy, and therefore have less greenhouse gas emission and ecological footprint. Traditional IAA in Asia has been developed and disseminated by farmers and local communities. It is highly contextualized according to locally available resources and social-economic settings, playing important roles in rural livelihoods, food security, human nutrition, and development of rural economy.

Considerable research and development has elucidated the scientific basis of IAA. Many new innovative IAA technologies and systems have been recently developed and practiced, which have shown great potential to improve sustainability of aquaculture. IAA continues to dominate production in Asia although science/industrial-based aquaculture technology using agro-industrially formulated feed is expanding rapidly, both geographically and in production. It is expected that IAA, potentially a more resilient food production system than monoculture, will be a renewed growth point of aquaculture, contribute to food security and nutrition for growing world population in facing resource scarcity, environmental pressure and impacts of climate change.

Agroecology is one of the new approaches to revisit aquaculture-agriculture integration. It consists of applying ecological concepts and principles in order to optimize interactions between plants, animals, humans and the environment, as well as social aspects. By creating synergies, agroecology contributes not only to food production, food security and nutrition, but also to the restoration of ecosystem services and biodiversity, which are essential for sustainable agriculture. It can play an important role in building resilience and adapting to climate change.

## 2. Scope of the regional review

This is a general overview of the major IAA systems in several Asian countries today - status, some details of current practices, and development trends. It should be noted that the types and extent of the diverse IAA systems in Asia are not recorded in official national or FAO statistics. Segregated production data on IAA, if they are available, are not readily accessible. Information on the technical specifications of some “emerging” systems has yet to be disseminated widely. Thus, the information is extracted from available published literatures, field experiences of authors, personal communication and internet. Some information still needs verification by national aquaculture personnel and field survey. The prospects for future development, including opportunities and constraints are outlined.
### 3. Definitions and characterization of IAA

Edwards (2019) defines integrated farming involving aquaculture as “aquaculture linked up with plant crop and/or livestock subsystems on a farm”. The linkage between two or more human activity systems (one or more of which may be aquaculture), can be either direct, with the activities linked on-site, or indirect through distant activities connected by transport, and with activities linked in terms of time either in parallel (at the same time) or sequentially (alternately, at different times).

The majority of IAA systems in Asia are extensive and semi-intensive. However, some recently emerging IAA systems can also be intensive in terms of aquaculture production.

Extensive systems depend on natural food produced within the system without nutritional inputs provided to aquaculture animals intentionally by humans. Natural food consists of some macrophytes, plankton suspended in the water column (bacterioplankton, phytoplankton and zooplankton) and benthos in sediments (insect larvae and adults, snails and worms) and is usually high in protein (50-70 percent dry matter). Extrapolated annual fish yields are usually less than 1 tonne/ha in extensive systems. Examples of extensive IAA are traditional rice/fish culture in China.

Semi-intensive systems depend on fertilization and/or on the addition of supplementary feed to complement high-protein natural food for cultured aquatic animals. Natural food is a source of minerals and vitamins and intentional fertilization aims to produce it in situ. Natural food provided in semi-intensive IAA systems is increased by organic fertilization with livestock or green manure (vegetation). There is also a residual fertilizer effect from uneaten fish feed and fish excretory products and faeces.

Traditional supplementary feeds are locally available plants and agricultural by-products, often with a low protein content that nutritionally complement high-protein natural food. The most common are rice bran, wheat bran, broken rice, and waste vegetables; volunteer (wild) or cultivated terrestrial vegetation e.g., grass and weeds; wild or cultivated aquatic macrophytes e.g. duckweed, water spinach and pond weed; agro-industrial by-products e.g. grain brans, broken rice and oil cakes; and also food processing wastes such as waste noodles and confectionary produce. Supplementary feed is traditionally fed as single ingredients, unprocessed and uncooked in pond culture in China and Southeast Asia although feeding practices in more recently developed aquaculture may involve mixed ingredients offered to fish in perforated sacs in some countries such as Bangladesh and India. Extrapolated annual fish yields range from 1-5 tonnes/ha for low-quality fertilizers and feeds, to 5-10 tonnes/ha for high-quality fertilizers (feedlot livestock manure).

Most IAA systems are semi-intensive e.g. rice/fish; crop/fish; livestock/fish. Those that use only on-farm inputs may be called direct IAA in contrast to those that use off-farm or local sources of vegetation, manures and agricultural by-products as nutritional inputs that are indirect IAA. Thus, some form of transportation is involved as inputs and production are not directly linked spatially. IAA are integrated with agriculture and animal husbandry because they provided the only sources of nutritional inputs for farmed aquatic organisms in the past, before the relatively recent manufacture of chemical fertilizers and formulated feed usually in pelleted form.

Intensive IAA systems are characterized by artificial feed input, often in the form of industrial manufactured, nutritionally complete pellets to primarily cultured aquatic animals. An example is the intensive culture of aquatic animals in earthen ponds integrated with production of a few secondary aquaculture species and aquatic plant/crop production in separate ponds in a recirculating system. In such a system, removal and reuse of nutrients from effluents of the intensive culture of the primary species are the major purpose of other farming activities/components. Other examples include aquaponics, intensive cage culture in earthen ponds, and some emerging systems such as in-pond raceway aquaculture, container-based aquaculture integrated with earthen ponds etc.
<table><caption>**Table 1:** System classification of IAA in Asia based on the production of the primary aquaculture component</caption><thead><tr><th rowspan="2">Aquaculture facilities</th><th colspan="3">Intensity of the primary aquaculture component</th></tr><tr><th>Extensive</th><th>Semi-intensive</th><th>Intensive</th></tr></thead><tbody><tr><td>Open-water-based</td><td>Culture-based fisheries</td><td>Culture-based fisheries</td><td></td></tr><tr><td>Trench/ditch-based</td><td>Fisheries in rice field</td><td>Integrated farming of rice and aquatic animals</td><td></td></tr><tr><td>Pond-based</td><td></td><td>Livestock/fish integration<br>Crop/fish integration<br>Crop/aquaculture rotation</td><td>Earthen-pond-based integrated recirculating systems<br>Crop/aquaculture rotation</td></tr><tr><td>Tank/raceway-based</td><td></td><td></td><td>Aquaponics<br>Container-based integrated recirculating system<br>In-pond raceway aquaculture system</td></tr><tr><td>Cage-based</td><td></td><td></td><td>Cage-in-pond integrated system<br>Cage culture in agriculture irrigation system</td></tr></tbody></table>

## 4. IAA practices

### Rice/fish culture

In a rice-fish culture system, a large area of rice field and a big volume of water provide essential living space and natural food for fish, which in turn, benefit rice production by suspending nutrients in soil into water column, reducing/eliminating weeds, controlling insects, loosening soil, and directly fertilizing rice field by fish excreta.

### System description

There are mainly two ways: co-culture of fish and rice where fish and rice are concurrently raised together and fish-rice rotation by alternating fish and rice crops. Rice/fish co-culture is more popular. It however requires good coordination and management of field activities such as application of the pesticides, chemical fertilizers, irrigation and land drying process.

A trench or ditch is usually dug in the rice field with excavated soil used to strengthen and raise the height of the dike to hold more water for fish and prevent fish from escaping. The trenches or ditches are usually 50-60 cm deep, occupying anywhere from <1 to 10 percent of total rice field. A larger area of trenches may result in lower rice yield. A 1.0-1.5 m deep fish sump or pond may be constructed in the middle of the rice field. The trench provides deeper and cooler water in hot weather for fish and a refuge when the field is drained for weeding, pesticide application and harvesting rice. Water sources are screened to prevent loss of fish or entry of wild species. Traditional rice/fish culture is mostly extensive, with fish consuming natural food that develops in the rice field.

Commonly cultured fish are herbivorous/omnivorous species such as common carp (Cyprinus carpio), Chinese carps, Indian major carps, silver barb (Barbonyrus gonionotus) and Nile tilapia (Oreochromis niloticus). Polyculture of multiple species of fish proves to be more effective in utilization of water space and nutritional niches. Extrapolated annual yields range from 100-250 kg/ha and to 1 tonne/ha or higher with supplementary feed if the trench is greater than 10 percent of the total area of the field. Rice yields are reported to increase by about 15 percent when fish are stocked, probably because farmers manage the water better. Fingerlings were traditionally nursed in rice fields in Indonesia. A rice-fish
system with large areas of trenches and fish sumps, and stocked with many fish e.g. one fish/m² needs intensive care, routine management and well-planned field activities.

# Country Overviews

## Bangladesh

Rice/fish culture was promoted as a technique for integrated pest management, as farmers who stocked fish in their rice fields reduced or eliminated the use of pesticides, but the extent of sustained adoption by farmers appeared to be limited (Nandeesha, 2004; Nabi, 2008).

Culture of high-value river prawn (*Macrobrachium rosenbergii*) has been developed recently in trenched rice fields with an abundant water supply in southwest Bangladesh. Post-larvae are nursed in trenches in rice fields and then are raised concurrently with rice as rains flood the field (Nandeesha, 2003; Ahmed *et al.*, 2013).

The feasibility of nursing common carp and Nile tilapia (*Oreochromis niloticus*) fry in irrigated rice fields in Northwest Bangladesh has been demonstrated and the practice has spread without further project support (Barman and Little, 2006; Haque *et al.*, 2010).

## China

Culture of a red coloured variety of common carp in stream-fed terraced rice fields in mountainous Qingtian County, Zhejiang Province has a documented history of 1200 years (Edwards, 2006; Lu and Li, 2006; Hu *et al.*, 2016; Ren *et al.*, 2018). Fish production is low but the fish have a high market value, because of their special taste with local households and restaurants involved in the tourist industry (FAO, 2016). The system has been listed by FAO, UNDP and GEF as a "globally important indigenous agriculture heritage system". More widespread dissemination of the system appears unlikely because of its special situation as a localized tourist site.

Culture of high-value crustaceans has been developed recently in trenched rice fields. River prawns (*Macrobrachium nipponensis* and *M. rosenbergii*), Chinese mitten-handed crab (*Eriocheir sinensis*), and the red swamp crayfish (*Procambarus clarkii*) are also grown concurrently with rice in trenched rice fields (Fang, 2003; Miao, 2010). Rice field aquaculture is now reported to occur on a massive scale in China with over 1.5 million ha and fish production from paddy field over one million tonnes.

In 2017, China established a national standard (SCT 1135) on "Technical Specifications for Integrated Farming of Rice and Aquaculture Animals" which came into effect in January 2018 to standardize and regulate rice-fish culture. In the Part I: General Principles, it is stated that:

a) Rice yield: not lower than 7 500 kg per ha in low lying plains and not lower than average paddy yield in hilly areas;

b) Area ratio of ditches/fish refuge to paddy field: not over 10 percent;

c) Net income improvement: In comparison with rice cultivation alone in the same conditions, the net income in terms of per unit farming area is improved by 50 percent;

d) Reduction of use of fertilizers: In comparison with rice cultivation alone in the same conditions, use of fertilizers is reduced by 30 percent;

e) Reduction of use of agriculture chemicals: In comparison with rice cultivation alone in the same conditions, use of agriculture chemicals such as pesticides etc. is reduced by 30 percent;

f) Use of medicines for fish: no antibiotics and anti-parasitic medicines are allowed.

## India

Rice/fish is being promoted for indigenous communities in northeast India (Sharma *et al.*, 2017).

## Indonesia

Rice fields used to be a major source of fingerlings in Java, Indonesia but the practice of rice field nursing had declined significantly in Cianjur, a major nursing area. (Edwards, 2009a). It was reported that a nursery pond converted from a rice field would produce double the number of fingerlings. More
recently it has been reported that the Government of Indonesia has launched a “one million-hectare rice-fish programme” (FAO, 2015). Furthermore, a tilapia farming company, Regal Springs, paid local farmers to raise tilapia fingerlings in their rice fields for stocking in company cages installed in reservoirs (Seaman, 2014).

## Viet Nam

Rice/fish culture in the mountains of Northern Viet Nam is a traditional practice (Le et al., 1995) but it also occurs throughout the country today. Some farmers in the Mekong River Delta in southern Viet Nam culture low-value fish such as common carp, kissing gourami (Helostoma temmincki), rohu (Labeo rohita), silver carp (Hypophthalmichthys molitrix) and Nile tilapia concurrently with rice. Culture of high-value giant river prawn has developed recently in well watered trenched rice fields in southern Viet Nam; post-larvae are raised concurrently with rice and then in rotation after rice harvest as rains flood the field (Nguyen et al., 2006).

## Constraints

Although rice/fish farming has been promoted widely, the degree of sustainable adoption has been rather limited (Nandeesha, 2004; Nabi, 2008). Capture and culture of fish in rice fields have both diminished over recent decades.

The practice is constrained by intensification of rice culture: high yielding varieties of rice that require water level lower than 20 cm and have a shorter growing period than traditional rice varieties make it difficult for fish to attain marketable size. Increased use of pesticides is another risk factor affecting health of both fish and human consumers. Further constraints are theft of fish as rice fields are often considered as a common property resource and are difficult to guard due to their large size and location often distant from the farmer's dwelling. The culture of aquatic animals in rice fields is mostly not attractive to farmers in terms of return to labour. It requires considerable time and labour to modify rice fields for fish culture by digging trenches and raising the height of the surrounding dikes; and to maintain adequate water for the fish in the dry season as well as to prevent loss of the fish through flooding in the rainy season. Furthermore, rice/fish integration is likely to become even less prevalent with new rice technology promoting less water use in view of the diminishing availability of water (Uphoff, 2007).

The majority of fish ponds in Asia have been constructed from rice fields (Edwards, 2015). Some countries today have policies restricting rice field conversion because of concerns about the national food staple, rice, e.g. China. Rice-based aquaculture is considered as a low-cost and low-risk entry point for farmers to carry out aquaculture without jeopardizing the sustainability of rice production in China but some farmers have been reported to still abandon rice farming and convert their fields to ponds. Other countries are allowing farmers in some areas to diversify agricultural production as rice usually does not provide an adequate income e.g. Viet Nam. Thousands of hectares subject to flooding and able to produce only one rice crop annually have recently been converted to fish ponds in the Red River Delta, Viet Nam.

## Future prospects

While there is a relatively low economic return on producing small fish in rice/fish systems, such fish may also provide an important source of animal protein, healthy fats, vitamins and minerals for poor farming households (Halwart, 2006). Consequently, there have been considerable efforts to promote rice/fish integration during recent decades, which should be continuously extended to small-scale farms wherever possible. It is an effective way to improve small-scale farming productivity with its flexible farming intensity, ready adoptability, and lower resource demand to entry.

There have been recent developments of intensification and diversification of rice-fish culture. Extensive operation has been evolving into more intensive culture characterized by better field layout and construction, more seed and feed inputs, and improved fish production. The systems have also diversified from a combination of rice and fish only to more complex integrated systems incorporating
the culture of other aquatic species, usually of high market value into rice fields in areas with an
abundant water supply in Bangladesh, China and Viet Nam.

## Pond-based IAA

Pond-based IAA systems (livestock/fish and/or crop/fish) have pond aquaculture as the major system components which either receive wastes and sub-products from other farming activities, for example, livestock production, to fertilize fish ponds for fish production, and/or recycle aquaculture pond nutrients and water back to support crop production.

Pond-based IAA systems probably originated in China, empirically developed through trial-and-error by farmers over centuries, and later spread to other countries in South East Asia. Similar traditional IAA systems that occurred in China probably spread more than a century ago to two other densely populated areas of Southeast Asian countries: West Java, Indonesia and the Red River Delta, Northern Viet Nam. IAA in other countries of South East Asia and South Asia, and regions of Indonesia and Central and Southern Viet Nam, probably developed less than a century ago.

There has been recent development to integrate crops and intensive culture of aquatic animals in earthen pond based recirculating systems. The system usually focus on intensive aquaculture with crop production as one of the measures to treat aquaculture effluents.

## System description

### (1) Livestock-fish integration

The most common example of IAA is the feedlot livestock/fish integrated farming that depends largely on manufactured formulated feed for the livestock: pig/fish, chicken/fish, duck/fish, and dairy cattle/fish integration (Little and Edwards, 1999, 2003). As the system is driven by off-farm formulated feed for the livestock, livestock production is intensive. Most of the food nutrients pass through the animal to provide high quality manure. The fertilized pond has high natural food production because of the nutrient-rich manure and it may also receive spilled livestock feed which further contributes to high fish production. Fish yields may be as high as 8-10 tonnes/ha/yr without any additional nutritional inputs.

Fish species in such system are mostly herbivores, omnivores and detritus feeders, such as carps and tilapia, which can use natural food produced by fertilization efficiently and are relatively tolerant to adverse pond environment and water quality such as Clarias catfish and Pangasius.

Feedlot livestock/fish is typical of suburban areas with access to agro-industrial products/by-products. Feedlot livestock/fish in rural areas is often associated with rice mills as the miller usually retains the rice bran which enables livestock to be raised in an intensive way.

A balance between livestock production and fish culture is crucial for a typical integrated livestock/fish farming system. Overloading wastes from livestock feedlots or poultry houses into fish ponds could result in water quality deterioration.

### (2) Crop-fish integration

Fish ponds provide a source of water to irrigate crops, so cultivation of plants such as vegetables and fruit trees on pond dikes is widespread, mostly for human consumption. Plants, in particular old or damaged leaves, can be fed to herbivorous fish or used as green manure.

Purposefully growing green forage for fish is also practiced such as in grass/fish systems where grass produced from the dike crowns or slopes are either used for feeds or for compost making. The common grass varieties for this purpose in China are rye grass (Lolium perenne), Sudan grass (Sorghum sudanense), elephant grass (Pennisetum purpureum), Astragalus sinicus, Comfrey (Symphytum peregrinum), hybrid penisetum (Pennisetum americanum x P. purpureum), Artemisia apiacea and even green cabbages.
There is also practice to grow fish and crop/grass in rotation, i.e, plants (grass or other crops), for example, Barnyard grass (*Echinochloa crusgalli*) and ryegrass, are cultivated on pond bottoms upon the completion of the fish cycle. The plants improve pond soil conditions through absorbing excessive nutrients in pond sediments and can be used as feeds for fish in other ponds. The grass is submerged when reaching 30-50 cm high and decomposed as a green fertilizer to enrich pond water with natural food before fish are stocked for aquaculture cycle

### (3) Earthen-pond-based recirculating integrated systems

Earthen-pond-based recirculating systems were probably developed initially for intensive shrimp culture to tackle the issues of excessive nutrient discharge from shrimp ponds. In such an integrated system, wastewater from shrimp ponds flows through sediment ponds, fish culture ponds (usually filter feeders are stocked such as tilapia, mullet, milkfish etc.), seaweed and shellfish ponds before recirculating back to shrimp ponds for reuse. The system was considered a better alternative to shrimp monoculture with improved nutrient utilization efficiency, and minimal environmental impacts. It has been successfully practiced at commercial scale for marine shrimp culture (Lin and Diana, 1995). Systems have been further developed for treatment and reuse of wastewater from intensive giant freshwater prawn ponds (Yuan and Yang, 2005), using filter feeding fish such as tilapia in combination with the cultivation of water mimosa (*Neptunia oleracea*). The advantage of such a system is its relative isolation from the surrounding environment, causing less pollution and less chance of introducing external pathogens and pollutants into culture ponds. Wastewater from intensive aquaculture ponds can stimulate the growth of plankton to support growth of filter-feeding fish and aquatic plants further absorb nutrients in water.

In China, a system has been developed to integrate pond fish culture with rice cultivation. The water discharged from aquaculture ponds enters an organic rice field and passes through the water distribution channels and catchment area in rice fields to purify. The water in rice field and the catchment can be recirculated back and reused in the aquaculture ponds. The system improves the overall profit by 20 percent, reduces the aquaculture water discharge by at least 60 percent and the pollutant discharge by at least 50 percent.

## Country overviews

### Bangladesh

Traditional polyculture of Indian major carps in Bangladesh was extensive but semi-intensive fish culture has been introduced through projects in the past three decades (ADB, 2005). Farmers attain extrapolated annual fish yields of 3-5 tonnes/ha in well-managed ponds, using on-farm and locally purchased manures, brans and oil cakes (ADB, 2005). Important introductions of exotic fish to the traditional polyculture of indigenous Indian major carps are grass carp, fed with on-farm vegetation such as grass, banana leaves and duckweed, and filter-feeding silver carp which grows rapidly in green water ponds and comprises a major part of the harvest.

Pond dikes are commonly used to raise fruit and vegetables (Ahmed, 2007; Edwards, 2007; Jahan *et al.*, 2015).

According to Hernandez *et al.* (2018), there has been a “quiet revolution” in the country’s aquaculture value chain, with a gradual shift from little use of any type of feed, to the use of on-farm feed resources such as cow manure and rice bran (direct integration), then to the purchase of the latter (indirect integration), and finally to the purchase of formulated pelleted feed without any integration. Poultry are sometimes raised on or near the pond.

### China

Integrated farming has a long history in China where traditional family-level integrated farms were widespread in the Yangtze and Pearl River basins before the development of communes and collective agriculture in the 1950’s. There is a voluminous literature on IAA in China (NACA, 1989; Mathias, Charles and Hu, 1994; Symoens and Micha, 1994).
The traditional Chinese system of carp polyculture has several on-farm linkages. Fertilizers included human manure or night soil, livestock manure, mainly pig, vegetation or green manure for crops and pond, as well as pond mud for crops. Supplementary feed for fish was provided by using wild grass from the farm and its vicinity; and wastes from vegetables grown for humans and pigs. Mulberry used to be grown for leaves to feed silkworms and silkworm pupae were a traditional high-protein fish feed. Night soil and pig manure were used to fertilize rice, vegetables and fish pond in decreasing importance; feed requirements of pigs were met before feeding fish. Pond mud was used to fertilize terrestrial crops grown on pond dikes. Indeed, ponds fertilized with green manure and fed grass as green fodder for grass carp (*Ctenopharyngodon idella*) develop thick deposits of organic-rich sediments. Few on-farm resources were directly used for fish pond, due to intense competition from crops and pigs on resource-poor, small-scale farms. The main input to the pond was wild grass of low nutrient value, so extrapolated annual fish yields were low, probably only 1-2 tonnes/ha.

The most complex IAA were developed in China during the era of communes and they reached their peak of complexity in the 1980s with intensification through direct and indirect integration. Improved grasses such as elephant and rye grass were cultivated on pond dikes to feed grass carp. Nutrient flows were also greatly increased through manure from larger numbers of integrated livestock and transport of urban night soil as crop and pond fertilizers, harvest of wild aquatic feed organisms such aquatic macrophytes and snails from nearby lakes and use of wheat and rice bran, soybean and rapeseed cakes as well as chemical fertilizers and pelleted feed.

Carp production in China surged following the introduction of a market-driven economy in the mid-1980s because it was more profitable than terrestrial farming but production exceeded market demand with a decline in aquaculture profitability (Ye, 2002). Large-scale integrated farms became less integrated following privatization, with a reduction in the number of subsystems. Crops were eliminated except for grass used to feed the relatively high-value grass carp broodstock. Small-scale livestock integrated with aquaculture has been replaced by more efficient and profitable large-scale, industrial livestock farms; pond fertilization during grow-out has declined with increasing intensification, so less manure is required as the ponds already have excess nutrients from the residual fertilizer effects of feed (Miao and Liang, 2007; Miao and Yuan, 2007). The centuries-old integrated mulberry dike/pond system also disappeared from the Pearl River Delta, along with an increase in intensive monoculture of high-value fish, giant river prawn and soft shell turtle from the late 1980s (Yee, 1999).

There has also been a rapid increase in the use of commercial feed with more than 10 000 aqua-feed mills today in China (Zhang et al., 2013). In the major Chinese carp farming areas, more than 95 percent of the farmers use manufactured feeds although some still used home-made feeds made from rice bran, soybean cake and wheat bran. However, some livestock/fish farms also do remain in China, particularly some small-scale duck/fish integration in Southern China.

## India

The State of Andhra Pradesh is called the ‘fish bowl’ of India because it produces about 0.8 million tonnes of Indian major carps, mostly rohu and catla. Production is mainly an indirect IAA based on local off-farm by-products such as feedlot chicken manure as well as inorganic fertilizers, and brans and oil cakes as supplementary feeds (Ramakrishna, 2007; Edwards, 2008; Abraham et al., 2010). Carp farmers are reluctant and cautious in using commercial pelleted feed as they remain to be convinced of the superior production and economic efficiency of pellets over traditional mash feed.

In a comparative study of farming practice in the two leading fish producing states of Andhra Pradesh and West Bengal a majority of the farmers in Andhra Pradesh were large-scale whereas in West Bengal farms were mostly small-scale integrated with duck rearing and horticulture (Abraham et al., 2010).

## Indonesia

A wide range of traditional integrated systems occur in West Java, Indonesia, both at small and large-scale (Edwards, 2009a). Feedlot livestock/fish integration (poultry/fish and small-scale goat/fish) is widespread. Giant gourami (*Osphronemus goramy*) is fed elephant ear plant (*Alocasia macrorrhizos*) leaves and water spinach (*Ipomoea aquatica*).
## Myanmar

Rather curiously compared to other Asian countries, pond fertilization has not been a widespread practice in Burmese aquaculture (Belton *et al.*, 2015, 2017). It has been estimated that about 80 percent of Burmese aquaculture production is indirect integration based on off-farm rice bran and peanut cake, the remainder using pelleted feed. Feedlot livestock/fish integration has been present for several years on a small-scale but poultry/fish has expanded recently on indirect integrated, large-scale farms.

## Philippines

There is limited IAA in the country with the most common freshwater fish, tilapia, being mostly pellet-fed (ADB, 2005).

## Thailand

Feedlot livestock/fish farms are widespread: pig/fish, duck/fish, broiler chicken/fish and egg-laying chicken/fish. In Central Thailand where feedlot livestock/fish integration is common, most farmers began as livestock farmers and dug the pond initially for collecting soil to raise the land on which the livestock quarters can be constructed to minimize the risk of flooding. Recently, there has been a decline in feedlot/livestock IAA. Much of the tilapia, the major freshwater species farmed in the country today, is raised in ponds with indirect IAA, using feedlot chicken manure as fertilizer and rice bran as supplementary feed. There is also some small-scale integration of the herbivorous silver barb (*Barbonymus gonionotus*) with soft plants such as water spinach in rural areas.

Livestock are increasingly raised in monoculture, without integration with fish, in biosecure industrial scale farms. Following the outbreak of highly pathogenic avian influenza (HPA1), commonly known as bird flu, concerns about biosecurity to minimize risk of animal and human disease reduced the integration of broiler poultry with pond aquaculture. Fish farmers were not allowed to purchase day old chicks to integrate with fish. The Thai government allowed the continued integration of egg-laying poultry with fish but the chicken houses had to be screened from contact with possible virus carrying wild birds.

## Viet Nam

Traditional IAA occurs in the country and especially in the River Delta where it has a long history. The Red River delta in Northern Viet Nam, one of the most densely populated areas in the world with over 1000 people per km², has a traditional small-scale integrated farming system known locally as VAC in which a polyculture of carps is raised in household-level ponds in association with livestock and crops (Luu *et al.*, 2002). VAC is an acronym for the Vietnamese words for garden (vuon), pond (ao) and livestock quarters (chuong). There are diverse linkages between VAC sub-systems, which vary with agro-ecological zone.

Livestock quarters for pigs and poultry are constructed adjacent to, or near, the pond so that washings and urine may be flushed or drained into the pond. Most households keep one to several pigs, and small herds of scavenging chickens or ducks, which may be caged at night. There may be a garden and/or an orchard. Annual and perennial crops are grown to provide year-round food for the household as well as to produce for market. Vegetables include cabbage, onion, sweet potato, tomato and water spinach. Fruit includes banana, litchi, longan, orange, papaya and peach. Pond water is used to irrigate crops. Leaves of vegetables are used to feed herbivorous fish or as green manure for the pond. Grass and other wild vegetation and chopped banana trunks are also used to feed herbivorous grass carp. Pond silt is removed annually to fertilize fruit trees and/or to provide a nutrient-rich layer of soil to cultivate vegetables. Extrapolated fish yields are 3-4 tonnes/ha in the 700-1 000 m² ponds.

As the traditional VAC system has fairly low yields, farmers now practice improved VAC with diversification of fish species such as Nile tilapia and use of pelleted feed to supplement the traditional pond inputs. However, pelleted feed is mainly used to fatten fish towards the end of grow-out culture, as it would not be profitable to use it throughout the growth period. Wide dikes created by pond excavation above the usual flood line are covered with vegetables and fruit trees. Some farmers grow high-value ornamental plants on pond dikes for sale.
The importance of VAC has long been recognized for household food security and increasingly as a source of income, as the rice-based economy is diversifying. Viet Nam has a policy of agricultural diversification because rice farming does not provide an adequate household income for small-scale farmers and the government now allows conversion of poor quality land, such as low-lying rice fields subject to flooding on which agriculture was not profitable, into fish ponds.

More recently feedlot livestock have become commonly raised, especially meat ducks, on small fenced areas of the pond and on the dikes.

Dike cropping of vegetables is also widespread in the Mekong delta (Nhan et al., 2007). Giant gourami is raised in the Mekong Delta, integrated with crop production as feed for the herbivorous fish.

## Constraints

### (1) Issues in adoption of livestock-fish integration by small-scale farmers

Most livestock/fish integration depends on manufactured formulated feed for the livestock so it is an intensive practice for livestock although ponds are fertilized with manure. The practice is in decline in most countries as livestock farms are increasingly run as separate, highly specialized enterprises. Chicken manure is now often only available from large industrial-scale farms in Thailand, with indirect integration with aquaculture (Thongrod, 2007). Some livestock/fish farms remain in China, particularly the small-scale duck/fish integration and the practice has recently expanded in Myanmar and Viet Nam.

The limited fish production of IAA with limited on-farm resources is attractive only to the poorest households in remote areas, with limited access to alternative income generations. Attempts to introduce feedlot livestock to increase small-scale farm fish production have usually been unsuccessful, mostly due to marketing issues including competition with large-scale farms.

IAA has developed to varying degrees in recent decades in many countries, especially in South and Southeast Asia. Livestock such as pigs and poultry usually scavenge for their food on small-scale farms so it is difficult and labour intensive to collect manure for aquaculture. If they are confined or housed to permit manure collection then they have to be fed with feed manually collected or purchased. Large ruminants e.g. buffalo and cattle are penned/corralled at night near the house to prevent theft so it is possible to collect manure. However, scavenging ruminant manure is a poor fertilizer. It may also be possible to collect some manure of scavenging poultry when they are confined at night and given supplementary feed. Small-scale ponds may be fertilized with livestock manure but there are constraints to reuse the manure in ponds: labour is intensive to collect and apply if the livestock are not located adjacent to or over the pond, alternative use for crops, and pond may be used for domestic water supply. There may also be insufficient in quantity as most farms are resource-poor and there are often alternative/competitive uses as crop fertilizers or as fuel in the Indian sub-continent.

### (2) Bird flu in poultry/fish integrated systems

Concerns about biosecurity to minimize the risk of animal and human disease have recently limited the integration of poultry with pond aquaculture. There is no evidence that poultry/fish integration has ever been involved in any outbreak of highly pathogenic avian influenza (HPA1), commonly known as bird flu. However, contract farming companies in Central Thailand stopped providing day-old chicks to broiler farmers operating open systems, including those integrated with fish ponds, after the 2003/2004 bird flu outbreak (Edwards and Mohan, 2007). Broiler farming is exclusively done on a contract basis with large companies providing day-old chicks and feed, and buying back birds at harvest, mostly for export. Only layer farms have been able to continue integration with fish in Central Thailand provided they follow the government regulation to screen the poultry house from wild birds and eggs are sold on the local market.

### (3) Issues with crop-fish integration

Crop-fish integration is labour and land intensive i.e. the ratio of land:fish pond ranges from 1-2:1. It is also labour intensive to collect wild vegetation. The food conversion ratio of vegetation is high meaning that the feed conversion efficiency is low as plants are mostly made of water with only about 20 percent
dry matter. There may also be anti-nutritional chemicals in plants. Pond mud may be removed once the pond becomes shallow to fertilize dike crops but this is also labour intensive and seldom carried out, especially in the humid tropics.

#### (4) Issues concerning earthen-pond-based recirculating systems

This type of system is superior to intensive monoculture in terms of ecological efficiency and environmental friendliness. However, more land is needed to build secondary fish ponds and/or plant growing areas, which entails a much lower economic return than monoculture per unit area of land. This is the major constraint that hampers adoption of the IAA system.

### Future prospects

#### (1) Poverty alleviation

Although there has been a decline in medium to large-scale IAA with the intensification of aquaculture and the increasing involvement of entrepreneurs to benefit from the profitability of aquaculture, there remains a role for IAA to help alleviate poverty for small-scale farming households. Recent studies have indicated that poor households received many benefits from fish production in Bangladesh (ADB, 2005; Little et al., 2007; Pant et al., 2014), Nepal (Farquhar et al., 2019); Pant et al., 2014), Philippines (ADB, 2005) and Thailand (ADB, 2005).

#### (2) Increase of productivity and profitability of small-scale farms

In many developing countries, the majority of farms are small-scale, dominant in numbers and arguably in farming area. Increase of productivity in small-scale farms is important and a solution to many of the issues we are facing today such as poverty and food security. It is however a major challenge to increase the productivity and profitability of small-scale farms. As a generalization, the profile of a typical Asian farm is: small farm area; crop dominated, usually rice; and livestock, 1-2 draught animals and a few scavenging pigs and/or poultry. Most small-scale farms have a poor on-farm resource base and therefore limited inputs and limited outputs (fish production), with most agriculture/aquaculture products being consumed by the household for subsistence (Edwards 2009b). In most of the tropics, fish yields of small-scale farms are usually low due to: limited indigenous technical knowledge, stocking of small fingerlings which may be predated by carnivorous fish, limited nutritional inputs so that surviving fish may not grow, and fish ponds constructed in infertile soils which may remain turbid due to suspended clay. When the water eventually clears and light penetrates to the pond bottom, the pond may become a 'weed filled hole' i.e., become infested with emergent aquatic macrophytes, with little to no space for fish and subsequent abandonment by the farmers. Small-scale farmers on nutrient-poor farms who aim to develop aquaculture as a major occupation need to import nutrients from off-farm to intensify production. This invariably leads to specialization with a reduction of farm subsystems or enterprises and on-farm integration.

Aquaculture intensification is essential in most cases to meet basic needs and to satisfy growing aspirations for a better life because of the declining size of farms. It is usually necessary to increase the input of off-farm nutrients, as there are limits to the export of nutrients from the farm through fish products. There must be a significant increase in nutrients to permit a significant increase in production (Edwards 1998). Semi-intensive aquaculture based on indirect integration with inputs sourced locally from off-farm (fertilizer, usually poultry manure; and supplementary feed, usually rice bran and oil cakes) would lead to considerable increased fish production and it has a huge potential for expansion as exemplified by recent experiences in South Asia (Bangladesh and India) and Southeast Asia, particularly Thailand.

#### (3) Earthen-pond-based integrated recirculating systems as system alternatives to intensive monoculture

Earthen-pond-based integrated recirculating systems could potentially be solutions for biological treatment of effluents and improvement of overall nutrient utilization of conventional intensive monoculture. It is not cost-effective (probably in most cases) to treat relatively dilute pond effluents by
conventional sewage treatment technology (Boyd *et al.*, 2007; Cripps and Kelly, 1996) and this kind of recirculating systems are especially relevant. Biological floating vegetation beds may also be introduced into the system to improve water treatment efficiency

# Tank/Raceway-based IAA

## System description

The aquaculture of primary species are carried out in tanks, modified shipping containers, or raceways and are integrated with other farming activities such as vegetable/fruit production in hydroponic systems, or pond culture of secondary aquaculture species and/or crop production.

### (1) Aquaponics

Aquaponics, the integration of aquaculture with hydroponics (the cultivation of vegetables without soil) has been run on a pilot scale since the mid-1970s. The best known is a commercial-scale system run as a prototype at the University of the Virgin Islands (UVI) (Rakocy and Bailey, 2003; Rakocy *et al.*, 2006). Tilapia are reared in tanks, fed with pelleted feed and the effluents are used to fertilize vegetables such as basil, lettuce and okra kept on floating sheets of polystyrene in hydroponic tanks. The system occupies 500 m² of land and can produce 4.2-4.8 tonnes of tilapia and 5 tonnes of basil, 2.9 tonnes of okra or 1 400 cases (24-30 heads per case) of leaf lettuce annually. The immediate potential is for premium markets in which consumers are willing to pay a higher price for high-quality fish and vegetables, so there are limited climatic and market niches. It is unlikely that aquaponics will ever contribute significantly to global fish production because it is technically sophisticated with high capital and operating costs and requires skilled technical personnel for management. It also has high energy inputs with high greenhouse gas (GHG) emissions per unit of production.

There has been a recent explosion of Research and Development in aquaponics. Farms based on the UVI design have been constructed and perform well at temperate sites in Australia, Canada and the United States of America and in the tropics in India, Indonesia, Mexico and Thailand (J.E. Rakocy, personal communication).

### (2) Container-based IAA

Container-based IAA has been developed recently in China. It integrates intensive fish culture in modified ship-containers and earthen pond culture of fish and aquatic plants. A standard container has a water holding capacity of 23-25 m³, where fish can be stocked at the density of about 2000 - 5 000 pieces per container depending on species and harvestable size. Fish are fed with commercial pellets, sufficient aeration and water quality is monitored in real time. Water from the container flows through a solid separation compartment before entering earthen ponds where filter feeding fish such as carps or tilapia are grown, water can further pass through vegetation area for further nutrient removal before recirculating back to the fish culture container. The ratio of containers to earthen pond ranges from one container to 500 - 1 000 m². Solid waste collected is usually used as a fertilizer for growing vegetables. Species cultured on a trial basis include tilapia, snakehead, large-mouth bass etc. for both advanced nursing and grow-out purpose. Fish production in the containers ranges from one to three tonnes per container.

### (3) In-pond raceway aquaculture system (IPRS)

Developed at the Auburn University with the investment from the U.S. soybean checkoff program, the In-Pond Raceway System (IPRS) creates a healthier environment with a riverine flow for fish and shrimp in pond raceways while greatly reducing the environmental impact. The system protects water quality by removing waste and recycling it for other uses, such as biodiesel and fertilizer. The pond water can be reused, leading to significant conservation of limited water resources. The technology is being rapidly adopted in China and throughout Southeast Asia.<fnref n="20" />

<footnote n="20">²⁰ For more information: www.soyaqua.org/technology/in-pond-raceway-system</footnote>
Raceways usually occupy 1.5-2 percent of the total area and species cultured in IPRS in China include grass carp, black carp, common carp, crucian carp, largemouth bass, channel catfish, tilapia etc. The production in raceways can be as high as 80-150 kg/m³, and the survival rate of fish can reach 95 percent.

Omnivorous fish are stocked in the pond and it should be feasible to integrate crop production into the pond such as growing vegetables, or to incorporate the concept of constructed wetland.

## Constraints

A tank/raceway-based system needs relatively high capital outlay to set-up and run. In addition, the technologies are relatively complex and there are intensive requirements for managing processes. Small-scale farmers may have difficulties to start up and operate.

## Future prospects

In a tank/raceway based system the primary cultured aquatic animals are confined in a relatively small space/culture unit with high stocking density to maintain a high level of aquaculture production while more land area can be used for water treatment, growing secondary aquaculture species and/or crop production. Small culture units for the primary species provide convenience for intensive management and integration of technologies such as smart control of farming process and automation. Tanks/containers/raceways can also be easily transported to different locations and are relatively flexible to fit into site conditions. For conventional intensive culture without proper effluent treatment, tank/raceway based systems are feasible alternatives that are more ecologically and environmentally friendly.

Aquaponics can be flexible in terms of scale, physical set-up, mobility, choices for fish and crops. An aquaponics system has considerably efficient use of water and nutrients, which is greatly relevant to aquaculture and vegetable production in places where freshwater is too scarce to support conventional aquaculture. Aquaponics also serves as a unique household food production activity in urban areas where land is expensive and space is limited.

## Cage-based IAA

### (1) Cage/crop integration

Small-scale cage farming occurs in Northern Viet Nam with grass and maize leaves used to raise grass carp. The system was probably introduced from Southern China where it was also reported. Grass and maize may be purposefully grown for this, but supply of industrial feed has become essential for production efficiency.

### (2) Cage-in-pond integration

In the integrated cage-cum-pond culture system, high-valued fish species are fed with artificial diets in cages, and filter-feeding fish species are stocked to utilize natural foods derived from cage wastes. This integrated system has been developed and practiced using combinations of catfish-tilapia (Lin 1990, Lin and Diana 1995) and tilapia-tilapia (Yi et al. 1996, Yi 1997, Yi and Lin 2000 and 2001) at the Asian Institute of Technology (AIT), Thailand, carp-stinging catfish (Wahab et al., 2005) and climbing perch - carps (Asaduzzaman et al., 2006) at the Bangladesh Agricultural University (BAU), Bangladesh.

The system has been extended in Bangladesh, Cambodia, China, Thailand and Viet Nam with various system configurations. Aquatic plants are occasionally used in the semi-intensive ponds for nutrient management in effluents.
### (3) Cage culture in agriculture irrigation systems

There is also considerable potential to expand cage culture in under-utilized reservoirs, lakes and rivers although fluctuating water levels in reservoirs used for irrigation and hydropower generation can adversely affect aquaculture due to drawdowns. The culture of fish in cages in irrigation canals also requires a coordination between the water authorities that manage the system and fish farmers. There was a recent massive caged fish kill due to a water shortage in an irrigation canal in Thailand in 2012, after the irrigation authority drew down a reservoir to increase the storage capacity in the coming monsoon season to reduce the chance of floods; the authorities had been instructed by the government to lower the level of water in the reservoir before the monsoon season to avoid having to suddenly release large volumes of water when the reservoir filled up, one of the causes of the massive flooding that had occurred in the country in 2011. Cage aquaculture in irrigation canals is prohibited in some countries because of concerns that it may reduce water flow and increase sedimentation in the canal (Dugan et al., 2007).

Agricultural water storage reservoirs are dual purpose water bodies as they are also stocked with fish in Israel (Hepher, 1985; Sarig, 1984) and more recently in Egypt where fish farms are prohibited from using water in irrigation canals (van der Heijden et al., 2013).

There used to be massive operation of cage culture in lakes, reservoirs, rivers, water canals in China, which is now under strict scrutiny and regulations, and in most locations where cage culture was prosperous in the past, it is now prohibited in an effort to curb the environmental pollution, protect and restore natural ecosystems.

### Integration of aquaculture and irrigation (open-water-based IAA)

More efficient use of water is a critical challenge in agriculture and aquaculture. This could be attained by integration of aquaculture with natural and constructed water bodies, many of which are used for irrigation. The productivity of water may be increased through the integration of aquaculture in irrigation systems (integrated irrigated aquaculture, IIA), essentially a non-consumptive activity with fish grown in the water on its way to or from agriculture (FAO, 2006). There are major reviews of the integration of aquaculture into small as well as large-scale engineered irrigation systems (Haylor, 1994; Murray et al., 2002).

### (1) Culture-based fisheries

Community or culture-based fisheries (CBF), usually conducted extensively in small water bodies, is an “underutilized opportunity in aquaculture development” (De Silva, 2003). CBF is a form of extensive aquaculture, ideally conducted in small water bodies that are incapable of sustaining a fishery of any scale through natural recruitment processes, but that adopts a stock and recapture strategy, suitably developed, and managed communally. CBF is a low-cost, environmentally friendly activity usually with seed stock being the only external input that engages rural communities. It requires limited technical expertise and or associated legislative changes. CBF aims at being an effective user of water resources for the secondary purpose of food fish production without negating and or negatively impacting on the primary use of water resources frequently is for downstream rice cultivation, and home garden cultivation. CBF often benefits rural communities, who tend to be relatively more impoverished compared to the urban counterparts, by bringing about additional income and also providing access to food fish, thus enhancing the nutrition of these communities. CBF is an easily adoptable strategy that could contribute significantly to increase food fish production in developing countries with inland waters.

Production of more fish from existing waters with minimal external feed inputs provides an important means to supplement conventional aquaculture practices. Aquaculture-based fisheries enhancements have been successfully implemented in more than 27 countries with an estimated production of 2 million tonnes of fisheries products (Bostock et al., 2010).
Culture based fisheries involve community consultation and resource appraisal, research into water bodies for CBF feasibility, decision on stocking density and strategies, stock management and harvest, and benefit sharing among community members.

CBF is believed to have a great potential to increase fisheries production as it has been estimated that there are 67 million ha of small water bodies in Asia, constructed mainly for irrigation (De Silva, 2003). The promotion of CBF is likely to deliver more immediate yield increases than investment in technology as it is technically simpler than conventional aquaculture although there are usually complex technical, social and institutional issues regarding biodiversity, access to water bodies, social equity arrangements, and competition of water use to be addressed (De Silva *et al.*, 2006).

## (2) Use of nutrients from aquaculture effluents to produce aquatic plants

In low-intensity pond culture effluent discharge is minimal, with little to no adverse environmental impact as significant amounts of wastes are treated by the pond ecosystem during the culture cycle (Bergheim and Asgard, 1996; Boyd *et al.*, 2007). But an increasing amount of waste is now discharged directly to the external environment, as a result of intensification of aquaculture production trend. It is not cost-effective to treat relatively dilute pond effluents by conventional sewage treatment technology (Boyd *et al.*, 2007; Cripps and Kelly, 1996). Pond effluent treatment options are to use effluents to irrigate crops, to treat effluents in constructed wetlands or settling basins, or to reduce or eliminate water exchange (Tucker *et al.*, 2008). It is land-intensive to treat effluents using constructed wetlands, settling basins or sedimentation ponds, as well as to fertilize semi-intensive fish ponds. Reuse of intensive fish pond effluents to fertilize adjacent terrestrial crops has been reported but is not widespread, in part because of limited opportunities for fish ponds to be located adjacent to terrestrial crops which could be fertilized.

A promising technology is to integrate aquatic macrophytes with aquaculture to take up nutrients from eutrophic water, either in fish ponds or in water bodies to which nutrient-rich pond effluents have been discharged. The role of fish in food security is well known but the considerable role that aquatic plants such as water spinach (*Ipomoea aquatica*) and water mimosa (*Neptunia oleracea*) play in food security is less well appreciated (Edwards, 2009b). Water spinach is inexpensive, provides high-quality protein, minerals and vitamins, and is easy to digest; all parts of the plant, the stem, leaves and especially the young apex, can be consumed.

Considerable quantities of edible aquatic plants are cultivated in Asia but their production and value are not recorded in the annual FAO statistics for aquaculture production, despite creating income and employment for a significant number of especially peri-urban households, and in many cases recycling and treating urban wastewater while producing a green and nutritious foodstuff consumed on a daily basis by millions of people (PAPUSSA, 2002). This is presumably because freshwater aquatic macrophytes "fall between two stools", being neglected by agronomists as they are aquatic and not terrestrial plant crops and by aquaculturists, a zoologically-dominated profession.

Water spinach in Phnom Penh, Cambodia, is mostly grown in floating beds secured by stakes by poor communities on the surface of a lake close to where the main city sewage is discharged untreated into the lake, accounting for nearly half of the total sales of fresh vegetables in the city. Although poor households benefit from farming aquatic plants, aquatic vegetable growers are often affected by wastewater related skin conditions from daily contact with wastewater in the lake although research has indicated that well-cooked aquatic vegetables do not pose a health risk to consumers. As the low-lying natural water bodies around the city where aquatic plants are farmed are threatened by an expanding city and increasing numbers of factories and industries around the lake, the future livelihood of the people who live around and depend on the lake is uncertain.

Over 80 percent of the total production of water spinach in Thailand, estimated at almost 60 000 tonnes, is produced in the central plains around Bangkok. Most is produced in former rice fields with inorganic fertilizers, although a lot is still produced in eutrophic canals.
A manual for the cultivation of the four most commonly cultivated aquatic plants in and around four South East Asian cities (water spinach; water mimosa, *Neptunia oleracea*; water dropwort, *Oenanthe stolonifera*; and water cress, *Rorippa nasturtium-aquaticum*) has been published (PAPUSSA, 2002).

Water spinach has also been reported to have a good purifying effect when it covers 10 percent of a tilapia pond area in an integrated system combining intensive aquaculture with semi-intensive fish farming and a constructed wetland (Laszlo Varadi, personal communication). Beside the high water purifying efficiency, another advantage is the low running and maintenance costs. However, there are also disadvantages, such as the purifying efficiency that varies with the weather, the land requirement that is high, as is the investment cost.

**5. Research and capacity building needs**

Decades of research since the early 1950's in different countries and geographic locations has elucidated the scientific basis and ecological principles of IAA, and developed a number of successful farming models. However, social-economic contexts and resource settings are changing and IAA practices need to evolve to keep up with the changes.

Research and development of IAA need to address issues at both ends of the aquaculture development spectrum - to increase productivity and profitability of small-scale resource-poor farms and to improve sustainability of conventional intensive aquaculture.

**Research on rural development contexts for IAA adoption:** There is no doubt that IAA is one of the most effective approaches to improve efficiency of small-scale farming in resource poor rural communities and that it should be promoted. It is unlikely that there would be any significant scientific or technical obstacles in this regards and the effectiveness of extension and adoption of IAA is much dependent upon proper social economic intervention. Therefore research on social dynamics, economic conditions and resource settings of rural communities where poverty still prevails warrants a priority. This is a prerequisite for extension of any farming technologies, including IAA to small-scale farmers. Careful evaluation and modification of IAA models are needed to contextualize them and fit them into local conditions.

**Research on IAA systems to improve aquaculture sustainability** should include studies:

(1) To evaluate and document newly emerging IAA systems on their ecological efficiency, economic viability and adoptability in different geographic locations with different socio-economic and resource settings. Indigenous knowledge and farmers' innovations should be fully respected and studied;

(2) To test and develop new IAA systems using agroecological principles and applying efficient engineering approaches as system alternatives to current prevailing unsustainable practices of intensive aquaculture.

**Research on integrated cluster/community-based farming with agro-ecological approaches and building of "agro-ecological communities/villages":** A farming community with common shared resources such as irrigation systems, water supplies and drainage, public wetland etc. is treated as an agro-ecosystem, within which resource use, farming activities, and probably family livelihoods are optimized using agroecological approaches.

Promotion of IAA through training and education has been a constant effort by various international, regional and national organizations such as FAO, the Network of Aquaculture Centres in Asia (NACA), the Freshwater Fisheries Research Institute, Wuxi, China (FFRC), and the AIT in the past three decades. Thousands of professionals have been trained on IAA and they have been playing key roles in IAA research, extension and practices. Many training and extension programs on IAA have been carried out at national and local level. Integrated aquaculture is also a key subject and important part of curricula in aquaculture-related tertiary and vocational education all over the Asia. However it remains a major
concern that many small-scale farmers don't have readily access to technical know-hows. Capacity building for farmers and technical assistance require continuing effort.

**6. Recommendations**

(1) International communities, national governments, and development agencies should continue to encourage and promote IAA development for poverty alleviation, rural nutrition and food security through policy support, capacity building and strategic investment on research and development.

(2) For most resource-poor small-scale farms, adoption of indirect IAA by importing locally available off-farm inputs such as fertilizers (mostly in forms of manures) and supplementary feed such as rice bran, broken rice, oil cakes, agro-by-products is a feasible and may be an effective start to improve farm productivity.

(3) Rice-fish integration remains the extension priority in rice growing areas with relatively abundant water resource. Intensification and diversification are encouraged, wherever resources allow, to increase fish production and profitability.

(4) Conventional pellet-fed aquaculture needs to adapt to more ecologically efficient and environmentally friendly farming methods by applying the agroecological approaches of using less land/water for intensive fish production but more land/water for nutrient reuse and water treatment. The alternative systems include tank/raceway-based IAA, earthen-pond-based recirculating systems, cage-in-pond systems etc. Cost effectiveness however should be taken into consideration in the system shift.

(5) Some IAA systems may be improved to produce chemical free or organic products, e.g. rice/fish culture, aquaponics, integration of fish ponds and organic rice field etc.

(6) Aquaponics of various types are the rationale choices for fish and vegetable production in places where water is not enough to support conventional aquaculture. It may also be promoted as a food production activity in urban areas.

(7) National governments are encouraged to set up policy frameworks to facilitate culture-based fisheries development and adopt CBF as a strategy to increase fisheries production for rural communities, contributing to food security, environmental protection and resource conservation.

(8) Cage culture in irrigation may be promoted but with careful assessment of the carrying capacities of water bodies.

(9) International collaboration is needed in research, development, information sharing and human capacity building. Organizations like FAO, NACA and some leading national institutes are recommended to play the vital roles in networking, coordination and cooperation.

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# THE SONGHAI RURAL GROWTH INITIATIVE: AN AGROECOLOGICAL AND SUSTAINABLE DEVELOPMENT ALTERNATIVE IN AFRICA

Fr Godfrey Nzamujo o.p.

*Developing an agroecological literacy and systemic worldview and the corresponding authentic technologies and practices to build sustainable agricultural farming systems to leapfrog productivity.*

## 1. The transition to integrated development systems

### Why the systems approach?

For a long time we have taken the species, subspecies or some other biological blocks as separate units of development. But now, modern sciences among other sources, are providing us with fundamentally different and refreshing information on the frameworks and organizational patterns of our planet. It has become quite clear now that the unit of development and sustainability is not any of these entities. Though autonomous, they are not independent units and cannot survive alone. In other words, they are not units of survival and cannot constitute separate sustainable units.

What survives and what is sustainable is the organism or biological unit-in-its-environment. Any organism that works or is forced to work only in terms of its own survival will invariably destroy its environment and, as we are learning from bitter experience, will thus destroy itself.

From the systems point of view therefore, the unit of development or survival is not the entity (humans, animal, fish or crop) at all, but rather a pattern of organization, developed and adopted by any of these entities in its interaction with its environment. We believe that is it time to abandon the linear and mechanistic world view that shaped the present day agricultural and food systems and embrace a systemic worldview.

A close look at the major crises facing the world today (food insecurity/poverty, unemployment, environmental degradation, etc.), reveals that they are all connected and in fact inseparable - suggesting that our present crisis is fundamentally a systemic problem that requires a systemic, holistic and broad based approach.

Unfortunately most of the solutions we have seen so far seem to be piecemeal and symptomatic therapies that hardly work. This is because, we have been trying to solve systemic problems in a piecemeal manner. In the best cases, these solutions are simply band aid endeavors. In most cases however, they end up creating more problems. The dominant and conventional aquaculture system today is a good example of this crisis. But once a systems view has been embraced by our agriculturists, scientists, engineers, political and corporate leaders, we will see the emergence of radically different kinds of sustainable practices and enterprises.

### The Songhai Initiative

Songhai believes that Africans in this 21st century have hit a point in history that calls for dynamics and orientations that are deeper and broader than previous attempts. Today's challenges require a radical shift not just in our vision of the world or our mentality and how we think, but in every sphere of our lives - from the way we see ourselves and relate to each other; from our relationship with the environment to our intellectual, scientific, technical and business orientations; from our production systems to the ways we exchange and consume our goods and services.

The Songhai program is built on the premix that agriculture, by its very nature is a systemic process and if it is done as it should be, could constitutes a radical and sustainable pathway to holistic solutions to our present day challenges. Some of the principles at play in this new paradigm are:

* synergy
* symbiosis

* complementarity

* collaboration

* supplementarity

We believe that the only sustainable pathway is how to harness these principles to invent and develop new and appropriate technological and developmental trajectories (Figure 1).

<figure><img src="image_26.png" /><figcaption>**Figure 1:** A system view of agriculture at Songhai.</figcaption></figure>

We believe that from seeing our planet from this world view, we will be in a better position to design and re-engineer our way out of these crises. This new paradigm has to be appropriated and deployed if we are really committed to creating designing and inventing organizations, industries, economic activities that would solve our present day problems.

The Songhai initiative is basically the harnessing of the principles of the systemic world view to build agro-ecological, sustainable and broad-based development programs in Africa. It is an integrated development system that organically create dynamic linkages and synergies within agriculture (livestock, fish and crops) and between agriculture, industry and services.

## Biomimicry

This approach is far from the conventional agriculture which is primarily a bio-chemical interventionist approach. We start by first learning and understanding the biological process of nature and then our agricultural practices and technologies will be essentially alignment of our designs and actions to these processes to enhance productivity. This is biomimicry and it is the only way that our incredible environmental and biological capitals can be sustainably deployed and harnessed. The resultant efficiency is mainly because this system enables different life cycles or metabolic networks involved to operate in a systemic, synergetic and efficient manner. We call it “Dancing with Nature”

## 2. An agroecological perspective of aquaculture at Songhai

### Songhai

Songhai as an innovative institution has five components to deliver its mission.
* It is an agroecological literacy and cultural reorientation center where the new and emerging world view, new ideas and the corresponding organisational and social values are developed and inculcated in the youths and future farmers.

* It is a technology park, where new techniques aligned with the new worldview are developed and contextualized.

* It is an industrial park and production centre, where techniques and ideas are turned into enterprises and into different types of production activities in an integrated manner.

* It is an incubation/training/human resource development centre- an effective incubation space where new competences are developed. Here, the trainees are equipped with the new vision and culture (systemic world view- component 1), new techniques and methods developed and deployed at the centres (Technology parks component2) and new practices/farming systems (Component 3) to enable them to become more productive and efficient. By participating in production activities, the trainees, facilitated by mentors who are practitioners themselves, develop organizational and managerial competences to enable them to become functional individuals and entrepreneurs.

* The large number of youths (especially former and potential migrants) seeking for enrolment at the various Songhai centers is not only a sign that this initiative is making agriculture attractive to the youths, but that it is also helping to reverse the massive rural exodus and illegal and hearth breaking immigration crisis that is taking place in Africa today; and

* It is a service centre. After training, the job is far from over. Trainees need to be leveraged with services such as marketing, input procurement, hospitality services, networking, financial/loan and advisory services to enable them to stand on their own and create synergy and cooperation among themselves.

## The Songhai Integrated system of production

In the Songhai Integrated system of production, the aquaculture program is seen as one of the key metabolic networks in harnessing the incredible environmental capitals (matter, diverse genetic resources and energy) in the African water bodies (Figures 2 and 3).

<figure><img src="image_27.png" /><figcaption>**Figure 2:** Integrated production system in Songhai</figcaption></figure>

<figure><img src="image_28.png" /><figcaption>**Figure 3:** Inputs and outputs of the agroecological aquaculture system at Songhai.</figcaption></figure>
The objective is not only to grow food (fish products) but also to enhance the overall productive capacity of the environment and strives to tackle the triple challenge of poverty/food insecurity, unemployment and environmental degradation in a holistic and systemic way.

Regenerative and sustainable aquaculture technologies constitute a central part of Songhai's drive to develop authentic technologies that bring into play the natural forces of synergy and amplification in nature that have been ignored by conventional methods. This method creates a probiotic environment that empowers the regenerative agents of nature to optimize the productivity of the whole system by creating dynamic linkages between different trophic levels (from micro-organisms that recycles nutrients, through intermediate levels like algae, daphnia, etc. to the fish population). The overall effect is the creation of a so-called “reverse entropy” (syntropy) and the “super enabling” conditions and environments like enzymatic actions, appropriate pH conditions, optimal oxygen levels etc.

## “Producing more and better with less”

Essentially this process strives to harness the regenerative forces/elements in nature to develop an agriculture that is not only multidimensional and multifunctional, but also enhances benevolent cycles and pathways as it:

a) Produces food in sufficient quantities and with qualities that promote healthy living, healthy aging, and disease prevention;

b) Enhances the environment (soil life, food web, soil structure, etc.);

c) Provides the framework for a new settlement model- Agro-hoods or Green Rural Cities;

d) Builds sustainability and biodiversity;

e) Provides raw materials for agro-industry;

f) Provides feed stock for renewable energy;

g) Creates employment, particularly for youths and women.

The merits of a development strategy based on this type of agriculture are not only safe, affordable, high yield, high quality and sustainable, it also addresses employment and environmental problems in both rural and urban areas and builds a strong base for an inclusive and broad-based economy.

A major value proposition in this endeavor is that as it breaks the vicious cycle of poverty, it counters the “scarcity syndrome” in the developing countries that underpins socio-economic conflicts by developing a natural and integrated farming system that is based on low cost inputs.

## 3. Illustrations of agroecological aquaculture at Songhai

### The species

<figure><img src="image_29.png" /><figcaption>Figure 4: The species farmed at Songhai.</figcaption></figure>
<figure><img src="image_30.png" /><figcaption>**Figure 5:** Breeders of common and African carps.</figcaption></figure>

<figure><img src="image_31.png" /><figcaption>**Figure 6:** African carp Megalops atlanticus, a new promising species for aquaculture.</figcaption></figure>

The growing-out facility

<figure><img src="image_32.png" /><figcaption>**Figure 7:** Ponds and concrete tanks used for aquaculture.</figcaption></figure>
<figure><img src="image_33.png" /></figure>

©Sonthai Center

<caption>**Figure 8:** Other facilities.</caption>
INTEGRATED AQUACULTURE - AGRICULTURE AND AGROECOLOGY IN
AQUACULTURE: VIEWS FROM EUROPE

Joël Aubin and Jérôme Hussenot

**1. Introduction**

The global food system is now facing a growing human demand and needs to deliver a sustainable and steady supply of food to guarantee food security and nutrition for all people, while also limiting climate change and sustaining biodiversity and ecosystem services (Foresight, 2011). The role of aquaculture in the resilience of the planet can however be discussed in light of diversity of its products, its environmental impacts and reliance on feed ingredients (Troell et al., 2014). Therefore, as claimed for agriculture, it is necessary to revise the design of aquaculture systems to increase production in quantity and quality while preserving the environment and, from a sustainability point of view, by considering economic robustness, development of high-quality jobs and building of new relationships among producers, consumers, and production systems.

In the European Union, average per capita fish consumption reached 25.1 kg per year in 2015, and the value of seafood imports in 2016 was EUR<fnref n="21" /> 24.4 billion (EUMOFA, 2017). Aquatic production is therefore an important challenge for European countries, although aquaculture is paradoxically characterized by its lack of significant development (except for salmon), despite the interest it has always aroused. Freshwater pond systems have existed for centuries. They were built for religious purposes in the Middle Age and still dominate large areas of landscape. Nonetheless, pond systems based on extensive polyculture are regularly replaced by more intensive systems. Abandoning pond causes changes in associated ecosystems, which are being covered by woody vegetation. Modern aquaculture developed in the 1960s, based on fish monoculture and supply of formulated feed. Advances in research allowed the reproduction of many species and the elaboration of efficient feed, even for the small larvae of marine fish. This control of life stages led to improvements in fish rearing and genetics. Freshwater pond species were replaced on the market by salmonids (e.g. Atlantic salmon, rainbow trout) and carnivorous marine fish (e.g. seabass, gilthead seabream, turbot, meagre, sole).

The overall rearing performance of farmed fish, especially their ability to convert feed to body weight, are better than those of traditional livestock (Fry et al., 2018). Nonetheless, fish biology limits N-protein retention to 15-35 percent, depending on the species and rearing practices. Thus, at best, 65 percent of the nitrogen provided to a fish raised in monoculture is lost as nitrogen compounds. Similar percentage can also be observed for phosphorus. Therefore, the trend toward fish monoculture implies not only an increase in management and control of the species but also an increase in nutrient losses. In livestock systems, most animal waste is reused in crop systems and contributes to feed production and maintenance of soil organic matter. Increased nutrient losses are only observed with excessive animal concentrations (e.g. feedlots) or huge number of farms in a given region (FAO, 2006).

In “modern” European aquaculture, recycling of nutrients within a production system or in connected agriculture systems disappeared. Thus, this kind of production system suffers from a double penalty: (1) the overall recovery of inputs remains low, meaning that farmers must pay for large amounts of inputs that are ultimately lost, and (2) the nutrient losses induce extra costs for water treatment, which has to be borne by farmers (water treatment devices, practices such as sea-cage rotation), society (environmental monitoring, water purification) and ecosystems (carrying capacity, environmental impacts).

As a consequence, aquaculture in Europe is not perceived positively. Critics of aquaculture highlight its impacts: pollution from fish waste, accumulation of organic matter in water bodies, spread of

<footnote n="21">²¹ EUR 1 = USD 1.1.</footnote>
diseases and parasites, use of medicines in the environment, escapees of domesticated species, degradation of coastal landscapes and fragile ecosystems, use of fish meal and oil in fish feeds, etc.

The European Union regulations are also restrictive. By setting water quality objectives, the regulations limit the size of existing farms and the creation of new farms. Moreover, European Union countries apply the same European Union directives differently, creating market distortions between neighboring countries. As a result, annual aquaculture production (including fish, crustaceans, mollusks and algae) in the European Union has plateaued at 3 million tonnes for a decade (FAO, 2016).

The fish farming sector is now considering two main strategies. One is to move cages further out at sea, where carrying capacity no longer seems to be a constraint, but which requires larger cages and infrastructure investments. The other is to design onshore Recirculating Aquaculture Systems (RAS) or Zero Exchange Systems to limit interactions with natural ecosystems and better manage waste, but this requires technological investments and more energy to operate (Blancheton et al., 2009; Martins et al., 2010).

## 2. Escaping the deadlock

### Conceptual frameworks

Different ways of thinking, adopted by fish farmers, emerged and influenced the perception of aquaculture systems in Europe. Sustainable development implies moving beyond technology-only approaches, towards recognizing connections with surrounding activities and the natural environment by introducing the idea of long-term impacts (Lazard et al., 2014). Nonetheless, the implementation and monitoring of the effectiveness of this approach remain a key question. Following the “ecological aquaculture” approach appeared to be a good solution as ecological aquaculture “not only brings the technical aspects of ecosystems design and ecological principles to aquaculture but also incorporates… social ecology, planning for human community development, and concerns for the wider social, economic, and environmental contexts of aquaculture” (Costa-Pierce, 2010). Ecological aquaculture greatly inspired the ecosystem-based approach to aquaculture (EAA), described and promoted by FAO (Soto et al., 2008; FAO, 2010). EAA is not considered a new paradigm; it is more an attempt to construct a common framework. One key point is not to consider the aquaculture systems as a separate activity but as a part of a larger system that includes and influences the landscape. Therefore, integrating aquaculture with other human activities, mainly agriculture (but also tourism, other economic activities…), is an essential factor to understand its influence on the sustainable development of a region.

This approach is also parallel to the raising awareness of the limits of intensive practices in agriculture and the need to develop agroecological practices. The term “agroecology” may refer to a practice, a science (Dalgaard et al., 2003) or a movement (Wezel et al., 2009). Agroecology emerged as a science in the 1930s but was popularized decades later by Altieri (1995). Later, Altieri (2002) developed five principles specifically dedicated to small-scale farming systems: (1) recycle biomass and balance nutrient flows; (2) achieve and maintain soil conditions (e.g. organic matter, soil biotic activity) that favor plant growth; (3) minimize losses of solar energy, air, water and nutrients (e.g. microclimate management, water harvesting, soil cover); (4) increase species and genetic diversity in time and space and (5) increase beneficial biological interactions that promote key ecological processes and services. These principles are based on two main concepts: (1) recycling nutrients and energy within agroecosystems increases their efficiency (i.e. increases productivity, decreases losses and pollutant emissions) and (2) maintaining diversity (mainly biodiversity) increases resilience, stability and robustness of agroecosystems. An agroecosystem is a modified ecosystem, managed by humans to extract resources through agriculture. This concept is complex due to interactions between
socio-economic and ecological processes (Conway, 1987; Garbach *et al.*, 2014). Currently, FAO embodies all these characteristics into 10 elements of agroecology.<fnref n="22" />

Introducing more ecology into aquaculture is therefore a goal, as shown by the concept of ecological intensification of aquaculture (Aubin *et al.*, 2019). This approach also embodies the concept of ecosystem services (MEA, 2005), which can be defined as services that ecosystems provide to humans. When ecosystem services are considered in agriculture, agroecosystems become not only sources of food but also sources of regulation and cultural services (Haines-Young and Potschin, 2013). Ecosystem services can be transposed directly to the aqua-ecosystems associated with aquaculture systems (Figure 1).

## Integration practices

Having intensive fish monoculture as a starting point in Europe makes changing practices difficult. Ecological intensification defines three sequential levels of aquaculture integration: (1) focus on inlet and outlet control, (2) reconsider the targets of the aquaculture system and (3) include ecosystem services when changing system's objectives. The first level consists mainly of feed-related choices: depending less on fish meal and oil from industrial fisheries and using associated strategies (alternate by-product sources, new ingredients, more recycled ingredients). In pond systems, using natural feed is also a strategy, with possible integration with agriculture by recycling livestock waste as an input. This traditional practice is still followed in some European freshwater polyculture ponds.

Controlling aquaculture waste is a classic problem. Since aquaculture emissions into water-bodies are a major concern, developing water treatment methods is an initial step for onshore aquaculture systems. By this rationale, adding a water treatment device creates an extra cost for the aquaculture system. Recirculating Aquaculture Systems are derived from this approach. In the best cases, RAS can be integrated with agriculture by exporting and reusing sludge (from suspended solids) as a source of organic matter for land-based agriculture.

More advanced water treatment methods may require specific changes to the production system and imply changing the production target and organization. In the Middle Age, aquaculture was integrated with agriculture when crops were grown in the bottom of freshwater pond, during a pond-drying year. This practice, still followed in parts of Europe, provides good yields of spring crops (e.g. maize, wheat, barley, oats, buckwheat), due to the nutrient-rich pond sludge, and increases fish yields in subsequent production cycles, possibly due to organic matter mineralization (Wezel *et al.*, 2013).

<footnote n="22">²² More information can be found at http://www.fao.org/agroecology/home/en/ (consulted August 2019)</footnote>
<figure><img src="image_34.png" /><figcaption>**Figure 1:** Aqua-ecosystem components involved in ecological intensification (Aubin *et al.*, 2019). A farming system is located in a territory connected to resource ecosystems which provide resources, inputs and functions to the farming system, and to receiving ecosystems where products are delivered as well as services and disservices (perceived as negative consequences).</figcaption></figure>

Aquaponics, the combination of aquaculture (usually RAS) and hydroponics, represents a new type of integrated aquaculture. Supported by the development of urban aquaculture, many small aquaponic projects are emerging in Europe. In aquaponics, dissolved nutrients provided by fish are reused as fertilizer in hydroponics. Different fish species have been tested (e.g. rainbow trout, common carp, ornamental fish, pike, perch) depending on the period of the year and production objectives, and many plant species have also been tested (e.g. lettuce, strawberries, tomatoes, aromatic plants). Aquaponics appears to be expanding in Europe but has yet to become economically viable there, unlike in the United States of America (Love *et al.*, 2015). Moreover, the true ability of aquaponics to purify water is regularly debated (Wongkiew *et al.*, 2017).

Co-producing food or other products by recycling aquaculture waste is the key idea behind the concept of Integrated Multi-Trophic Aquaculture - IMTA (Neori *et al.*, 2004; Troell *et al.*, 2009; Barrington *et al.*, 2009; Chopin, 2013). IMTA is based on combining complementary species with trophic habits and living in different compartments of the ecosystem. Inorganic and organic wastes from fed aquaculture species (e.g. finfish) are respectively assimilated by autotrophic (e.g. phytoplankton, macroalgae, plants) and heterotrophic species (e.g. oysters, mussels, sea cucumbers) that are co-cultured with the fed aquaculture species. Thus, the generic concept of IMTA covers a large set of practices based on the complementarity of productive compartments and is applied to many groups of species inhabiting different ecological niches (Figure 2). Different types of integrated rearing systems have been developed in temperate and tropical areas, such as the association of Atlantic salmon (*Salmo salar*), macroalgae (*Saccharina latissima*) and mussels (*Mytilus edulis*) in Canada (Barrington *et al.*, 2009) or a macroalgae-scallop, urchin-gilthead seabream, or seabream-mulletts associations in Israel (Shpigel *et al.*, 2016; Neori *et al.*, 2017). IMTA can also be designed by using aquatic macrophytes to purify water and provide an alternate source of food for fish. Improvement of water quality by macrophytes has been well studied and tested under field conditions (Hasan and Chakrabarti, 2009). In saline aquaculture, halophytic macrophytes are also used in constructed wetland systems to treat effluents (De Lange *et al.*, 2013) or produce biofuels (Sharma *et al.*, 2016)
Inset A: European IMTA system: IMTA FISH / SEAWEEDS

Commercial companies
FRANCE (FMD), Portugal (ALGA+)

<table><tr><td>Main species</td><td>Seabream (Sparus aurata)</td><td>Ulva [Ao-nori] (Ulva rigida)</td></tr><tr><td>Rearing technique</td><td>intensive or semi-intensive [Pt]</td><td>IMTA in earthen ponds [Fr]<br>IMTA in open raceways [Pt]</td></tr><tr><td>Rearing period</td><td>all the year, 12/12</td><td>March to Nov. [Fr]; 12/12 [Pt]</td></tr><tr><td>Ulva production in IMTA for 2018</td><td>and production potential into brackets [metric tons]</td><td>France (FMD): 11 [700]<br>Portugal (ALGA+): 45 [180]</td></tr><tr><td>Product quality</td><td>seabream, meagre juveniles [Fr]<br>organic seabass, seabream [Pt]</td><td>food grade [Fr]<br>organic label [Pt]</td></tr></table>

<figure><img src="image_35.png" /><figcaption>ulva (sea salad)</figcaption></figure>

<figure><img src="image_36.png" /><figcaption>France, Oléron Island: FMD</figcaption></figure>

On the right the algae ponds,
on the left the fish hatchery-nursery

<figure><img src="image_37.png" /></figure>

<figure><img src="image_38.png" /><figcaption>Portugal, Ria de Aveiro: ALGA+</figcaption></figure>

In the foreground the seaweed raceways,
In the distance the earthen fish ponds
open raceway ponds in Portugal

References:

Roblin (2019).

Abreu (2019).

(Credit for the pictures: Jérôme Hussenot)
<figure><img src="image_39.png" /><figcaption>**Figure 2:** Representation of Integrated Multitrophic Aquaculture used in the IMTA-Effect Eranet-CO FASP project (Aubin *et al.*, 2017).</figcaption></figure>

In Europe, IMTA began in the 1990s, mainly by treating fish waste with microalgae (Hussenot *et al.*, 1998, Hussenot, 2003; Lefebvre *et al.*, 2004). The idea was then further developed as a way to reuse macroalgae produced for nutritional or industrial purposes (Santos, 2006). It was also adapted to the production of halophytes *Salicornia* in constructed wetlands, in Israel, Wales and Portugal (Webb *et al.*, 2012; Shpigel *et al.*, 2013). More complex systems have since been developed to reuse plants produced with wastewater to feed other species like microalgae for oysters (Lefebvre *et al.*, 2001; Li *et al.*, 2019). These experiments have yielded interesting results but require a precise management of the ecosystem compartments as well as the management of some limiting factors such as silicates for diatom microalgae growth.

In Europe, IMTA has developed in three ways. The original approach, combining fish in traditional sea cages with macroalgae and bivalves, exists but remains uncommon (Hughes *et al.*, 2016). The second approach combines several onshore monoculture systems in series (finfish, algae, mollusks or detritivorous organisms); it is better suited to RAS and requires extensive knowledge and technology. Fish and macroalgae (Inset A), fish and halophytes (Inset B) are the first land-based systems in series developed in Europe in commercial fish farms. The third approach puts all species in the same freshwater or coastal pond; it requires little technology, but the species interactions still need to be analyzed and managed. One example in Europe is the polyculture shrimp-oyster developed in France from more than twenty years (Inset C). Another one, experimented in Portugal is to mix fish, oysters and macroalgae in earthen ponds (Cunha *et al.*, 2019; table 1). It shows the advantages of mixing these species.

Intermediate systems can also be imagined. For example, ragworms (*Nereis virens*) were produced intensively in Netherlands to feed sole juveniles (*Solea solea*) in the same pond, and microalgae were produced using effluent water to feed bivalves, each species being in a separate pond (Ruizeveld de Winter, 2014).
<table><caption>**Table 1:** Comparison of rearing performances of fish polyculture: Meagre (*Argyrosomus regius*), white seabream (*Diplodus sargus*), and flathead mullet (*Mugil cephalus*), supplemented with oyster (*Crassostrea gigas*) and/or macroalgae (*Ulva* spp.). SGR: Specific growth rate, FCR: feed conversion ratio. Adapted from Cunha *et al.* (2019)</caption><thead><tr><th></th><th></th><th>Fish, oyster, phytoplankton, seaweed</th><th>Fish, oyster, phytoplankton</th><th>Fish, phytoplankton, seaweed</th></tr></thead><tbody><tr><td rowspan="2">Meagre</td><td>Harvested Biomass (kg)</td><td>865</td><td>861</td><td>603</td></tr><tr><td>SGR (percent per day)</td><td>0,43</td><td>0,44</td><td>0,29</td></tr><tr><td rowspan="2">White seabream</td><td>Harvested Biomass (kg)</td><td>160</td><td>135</td><td>145</td></tr><tr><td>SGR (percent per day)</td><td>0,53</td><td>0,46</td><td>0,5</td></tr><tr><td rowspan="2">Flathead mullet</td><td>Harvested Biomass (kg)</td><td>120</td><td>90</td><td>109</td></tr><tr><td>SGR (percent per day)</td><td>0,24</td><td>0,12</td><td>0,21</td></tr><tr><td rowspan="2">Total fish</td><td>Harvested Biomass (kg)</td><td>1115</td><td>1087</td><td>857</td></tr><tr><td>FCR</td><td>1,59</td><td>1,65</td><td>2,46</td></tr></tbody></table>

### 3. Constraints

IMTA remains in its infancy in Europe, in part due to a variety of constraints (Kleitou *et al.*, 2018). Starting from well-managed fish monoculture systems, the addition of ecological compartments to produce additional species using fish waste requires investments of time, knowledge and infrastructure that must be compensated by an increased income from the additional species. How to earn this additional income is not always clear, however, since the market of the new species may be small. Moreover, the use of additional resources, even with the objective of environmental improvement, does not necessarily lead to overall environmental benefits (Mendoza Beltran *et al.*, 2018).

The European Union regulations also limit IMTA, in particular because of the prohibition to feed animal waste or by-products to domestic animals. Consequently, the legal status of detritivorous species (e.g. sea cucumbers) and filter feeders (e.g. mussels, oysters) reared in IMTA for human consumption remains unclear. Regulations adapted to IMTA are needed to ensure that it continues to develop. There are also questions about consumer perception, especially of filter feeders produced by IMTA (Alexander *et al.*, 2016). Focused communication and quality control must be organized to ensure access to markets.
Inset B: European IMTA system: IMTA FISH / HALOPHYTES

Pilot or experimental stages
UNITED KINGDOM, PORTUGAL

<table><tr><td>Main Species</td><td>Marine Fish</td><td>samphire (Salicornia europea),<br/>sea aster (Aster tripolium),<br/>sea purslane (Halimione portulacoides), ...</td></tr><tr><td>Rearing technique</td><td>intensive or semi-intensive</td><td>Constructed wetlands or hydroponics</td></tr><tr><td>Rearing period</td><td>all the year</td><td>March to Nov. [UK] ; 12/12 [Pt]</td></tr></table>

Number of studies per halophyte species where phytoremediation was tested and growth performances evaluated upon irrigation with saline aquaculture wastewater. Source: Custódio *et al.* (2017).

<figure><img src="image_40.png" /></figure>

<figure><img src="image_41.png" /><figcaption>Constructed wetland developed in the Seafare project</figcaption></figure>

<figure><img src="image_42.png" /><figcaption>Samphire (Salicornia europaea)</figcaption></figure>

<figure><img src="image_43.png" /><figcaption>Sea purslane (Halimione portulacoides)</figcaption></figure>

<figure><img src="image_44.png" /><figcaption>Sea aster (Aster tripolium)</figcaption></figure>

References:

Webb *et al.* (2012).

Marques *et al.* (2017).

(Credit for the pictures: Jérôme Hussenot)
## 4. Perspectives

Combining multiple species into the same production system is a real opportunity for aquaculture; however, the perspective must change from waste treatment to a genuine multi-species integration. Moreover, species interactions are not only trophic; integrated aquaculture must also consider other types of interactions that influence the performance of systems, such as aquatic animal health improvement with decreased occurrence of diseases and parasites, or the improvement of animal behavior and welfare. Knowledge about these topics exists but is scattered; it must be strengthened to become truly useful.

As supported by agroecology, the sustainable use of natural environment factors as production factors must also increase. Natural primary production and invertebrates that develop naturally in and around aquaculture systems must be considered as supplemental food resources. Knowledge on microorganisms, a large part of the biodiversity and productivity of natural ecosystems, and key to their functioning, must also be strengthened.

In general, interaction with biodiversity is a major aspect for the sustainability of open and semi-open aquaculture systems. Aqua-ecosystems may be considered to restrict natural biodiversity, but they also support and stimulate it (FAO, 2018). One interesting perspective for future research is how to use agroecological practices to improve interactions between aquaculture and surrounding biodiversity. This role of biodiversity support is usually related to the ecosystem services provided by the aqua-ecosystem.

While species interactions and the supply of different products for different markets makes integrated aquaculture more robust, associated economic models must be built and strengthened. Developing viable commercial-scale systems in Europe remains a challenge.

## 5. Conclusion

In Europe, traditional integrated aquaculture-agriculture has been slowly replaced by intensive monoculture. Pond aquaculture still exists in some landscapes, in which nutrients from livestock waste sustain primary production and pond sludge is used to grow crops. They are, however, all semi-extensive systems with low yields. Ancient polyculture systems are now being reinvestigated to help design new systems. In particular, IMTA combining fish, primary producers and secondary producers recycling organic matter are based on the same principles. Due to production limitations and regulations, applying integrated aquaculture in Europe remains complex. Nonetheless, it has the potential to be productive, resilient and robust, providing high-quality and environmentally friendly products, which society expects from aquaculture systems.

## 6. Acknowledgement

This paper was written with the support of the IMTA-Effect, European Union ERANET-Cofasp project. The authors thank Michael Corson for his advices and proof reading.
## Inset C: European IMTA system: POLYCULTURE SHRIMP/OYSTER

### Commercial level
FRANCE (Atlantic coast)

<table><tr><td>Species</td><td>Kuruma shrimp (Marsupenaeus japonicus)</td><td>Pacific oyster (Crassostrea gigas)</td></tr><tr><td>Rearing technique</td><td>Marine pond extensive</td><td>Marine pond extensive / semi extensive</td></tr><tr><td>Initial density</td><td>1-5 i/m²</td><td>2-5 i/m²</td></tr><tr><td>Rearing period</td><td>May to October (3-5 months)</td><td>June to December (4-6 months)</td></tr><tr><td>Total production (IMTA and monoculture, 2018)</td><td>~ 50 MT</td><td>187 MT</td></tr><tr><td>Number of producers (IMTA and monoculture, 2018)</td><td>30</td><td>112</td></tr><tr><td>Selling price by producers</td><td>40-50 €/kg</td><td>10-20 €/kg</td></tr><tr><td>Product quality</td><td>«Crevette impériale» (Label BIO)</td><td>«Pousse en claires» (Label Rouge)</td></tr></table>

<figure><img src="image_45.png" /><figcaption>Production area « Charente-Maritime »</figcaption></figure>

<figure><img src="image_46.png" /><figcaption>Kuruma shrimp (Marsupenaeus japonicus)</figcaption></figure>

<figure><img src="image_47.png" /><figcaption>Pacific oyster (Crassostrea gigas)
(Credit for the pictures: Jérôme Hussenot)</figcaption></figure>
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# MALAGASY RICE-FISH FARMING

Jean-Michel Mortillaro and Lionel Dabbadie

## 1. Introduction

Some integrated aquaculture and agriculture systems (IAA) such as Chinese rice-fish farming are possibly as old as 2000 to 8000 years (MacKay, 1995; Edwards, 2019) and overtime, other integrated systems also emerged in both marine and freshwater environments, in temperate or tropical countries. Even though some gradually fell into disuse to make room for intensification and monoculture, IAA systems are nowadays rediscovered for their benefits that contribute to many of the sustainable development goals. Indeed, IAA systems are designed to decrease the farmers' dependence on external inputs, and to increase the whole system efficiency by optimizing the use of nutrients, energy and water. IAA systems also permit to diversify farm production and to generate a more resilient source of income, less dependent on mono-product marketing. Finally, they also generate and use different types of ecosystem services. In rural areas with low input availability and incomes, IAA systems bring the opportunity for farmers to extensively produce fish when intensive aquaculture is not within their technical reach. This is particularly the case in Madagascar where integrated rice-fish farming has been promoted by FAO since 1985 and by the non-governmental organization APDRA since 2006 (Dabbadie and Mikolasek, 2017).

Madagascar is an island country, located off the southeast coast of Africa. Frequently ranked among the poorest and most vulnerable nations, it faces several critical challenges (The World Bank, 2019). Food security and nutrition is one of them. Indeed, whereas rice is locally the main staple and main crop, the national production is insufficient to meet the demand, despite a mean yield of 2.5 t/ha and an estimated production area of 1.2 million hectares (Andriamparany, 2010). Malnutrition is another recurring issue in Madagascar, especially for children, as low household incomes limit access to a diversified diet (Razafiarisoa et al., 2009). For example, fish consumption is reported to be as low as 1.3 kg/capita/year according to official statistics (Rakotomalala et al., 2017), whereas the global average is now higher than 20 kg/capita/year (FAO, 2018).

To cope with these issues, the integrated production of fish with rice in paddies appeared as a promising technology, as it allows to harvest a double crop from the same field, and to benefit from synergies between them. Integrated rice-fish farming increases diet diversity, food security and nutrition, improves farmers' income and, overall, improves livelihoods in the rural areas through diversification and intensification of crop productions (Tsuruta et al., 2011). However, given the low availability and accessibility of production inputs to farmers, rice-fish farming in Madagascar needs to focus on improving the productivity of both rice and fish by minimizing inefficiencies and effectively recycling wastes or by-products.

## 2. Ecological basis of rice-fish farming

Irrigated rice fields are ecosystems favorable to the growth and production of aquatic organisms. They can even play a major role in feeding and nutrition of local communities as a source of self-recruiting species. Flooded rice fields are composed of several trophic compartments, the main ones being rice, water and sediment (Figure1). But insects, snails and weed are also commonly encountered in flooded rice fields as a result of the abundance of natural food and nutrients. They are often considered pests for rice, resulting in the intensive use of pesticides in modern rice crops. But self-recruiting species or stocked fish for aquaculture purpose, freshwater prawns or crabs also give value to these organisms by consuming them and recycling the nutrients they contain.

On the other side, the use of pesticides, fortunately limited in IAA, can affect the survival of most organisms encountered in the rice fields and on the overall trophic foodweb. Fish, crabs and prawns
rely directly and indirectly on phytoplankton and zooplankton produced in the water column. Sediments also host a multitude of invertebrates such as freshwater mussels, bacteria, biofilms and many other macro- and micro-organisms, all contributing to the trophic functioning of the flooded rice fields. Lastly, frogs, tadpoles, birds, snakes and rats are also not uncommon as they are looking for shelter or forage on the food resources of the rice fields.

<figure><img src="image_48.png" /></figure>

© Joan Michel Morillano

<caption>**Figure 1:** Schematic representation of the food web in a flooded rice field.</caption>

If wild fish, mostly consisting of various species of tilapias, have been traditionally harvested in Madagascar rice fields, technologies introduced since the middle of the 1980s were aiming at intensifying the rural fish production by promoting improved rice-fish farming practices and stocking common carp fry (*Cyprinus carpio*) in the irrigated rice fields. Besides the interest of this fast-growing species for its adaptation to the water temperature of Madagascar highlands (14 to 26°C), common carp also feeds through bioturbation on the bottom, which has been demonstrated to increase the oxygen supply to a greater depth in fishpond soil, thereby improving its quality (Ritvo *et al.*, 2004). Furthermore, common carp have been considered as ecosystem engineers affecting the water transparency and community composition (phytoplankton, zooplankton, macroinvertebrates and submerged macrophytes; Matsuzaki *et al.*, 2007). Matsuzaki *et al.* (2007) also demonstrated the effect of common carp on nutrient dynamics through excretion as a primary mechanism. Nutrient excretion by common carp should occur, as stated previously, while foraging on macro-invertebrates and weeds thus fighting against rice pests. Also, common carp can limit the growth of phytoplankton and submerged macrophytes (weeds) that compete with rice for nutrients, by affecting water transparency. Therefore, common carp are particularly adapted to the IAA context of rice-fish farming in Madagascar.

**3. Malagasy rice-fish farming study case**

Rice-fish farming has been carried out traditionally in the irrigated rice plots of Madagascar highlands (Kutty, 1987), which consist of four major ecosystems:
* Swamps, where rice is cultivated by farmers without modification of the landscape.

* Rainfed hillsides, where poor water management may lead to flood and drought (Fujisaka, 1990).

* Floodplain rice, where rice plots are characterized by more than 10 consecutive days of medium to deep flooding (50 cm flood to more than 300 cm) during the production cycle (Greenland, 1997) and where the water supply depends on rain and river flow.

* Irrigated leveled rice terraces, where fields are bunded with water control systems.

Fish can be found in all these ecosystems except in the rainfed hillsides. Nonetheless, floodplain rice and swamps are not appropriate for fish farming considering the risk of fish escapees during flood episodes. Even though the harvest of wild fish trapped in paddy fields during rice culture is widely practiced, intensifying the production through improved rice-fish technologies and stocking of farmed fish, faces several technical and social problems:

* One is the fear of fish theft, often associated or even confused with mortality through predation on fry (e.g. by birds, aquatic insects, snakes).

* Another one is the poor rearing or fish handling/transport conditions due to the lack of technical knowledge.

* The water management is also frequently questioned. This is particularly the case for the plots with raised bunds built to increase the water level for fish and that use new technologies that promote periodic drainage and drying to fight weeds and oxygenate soils.

* The use of refuge channels dug inside the plots to shelter fish in case of heat or drought, is also often seen as problematic because it leads to a loss of cultivable surface for rice. However, the loss of area is assumed to be offset by the increased rice yields observed with IAA, according to the FAO technical manual for dissemination of rice-fish culture (Kutty, 1987).

The technologies allowing an improved water management through raised bunds and refuge channels were therefore evaluated and compared to traditional practices in rural areas. The objectives of the case study were to characterize the agronomic performance in traditional (rice + self-recruiting species) and integrated systems (rice+carps). This was achieved by measuring the weight of commercial and self-recruiting species, as well as the yield of rice at harvest.

Farm experiments were conducted twice during a dry (2016-2017) and a wet (2017-2018) campaign. During the dry campaign, the first experiment consisted of six rice plots of 467 to 863 m² (total of 3 882 m²) randomly distributed in two treatments: traditional (rice + self-recruiting species; n=3) and integrated systems (rice+carps; n=3). The rice plots were located near the village of Tsiafahy, Antananarivo (-19.06, 47.61; Figure 2) and investigated during a 100 days cycle, beginning on the 11 January 2017 with fish stoking in integrated systems plots. Eight additional plots located in the village of Fihaonana, Antananarivo (-18.66, 47.17; Figure 2) were added during the wet season. These rice plots measuring 270 to 655 m² (total of 3 552 m²) were receiving two treatments: integrated (rice+carps; n=3) and fed systems (rice+carps+feed; n=5). Feed provided to the fish in the last treatment consisted of food remains, cow dung and termitary collected locally.

The second experiment started on the 04 December 2017 in Fihaonana and on the 28 January 2018 in Tsiafahy, and lasted for 98 and 89 days, respectively. Fish in each rice field were sorted by size and weighed at stocking and harvesting. Survival rate was calculated. Rice yields were also evaluated through three replicates, with a surface of 0.25 m², sampled randomly in each plot.