Aquaculture is widely recognised as a way to reduce malnutrition and poverty. So far, research has mainly focused on Asia, and the few studies available from sub-Saharan Africa are predominantly ex-post partial analyses. By constructing a village computable general equilibrium (CGE) model, we aim to investigate whether aquaculture improves local livelihoods and simultaneously has the potential to counteract local overfishing. We apply this to a rural case study region in Namibia where malnutrition, poverty and fish resource overexploitation are current problems. Our village CGE model shows that aquaculture would be a viable livelihood activity improving household incomes and utility through labour reallocations. Furthermore, aquaculture can counteract malnutrition through increased fish consumption. Higher opportunity costs lead to households leaving the fisheries and switching to aquaculture. These substitution effects offer the possibility of reducing the pressure on local freshwater fish stocks. Policy makers can use the results to introduce aquaculture interventions in rural areas. Our findings indicate that such interventions should take particular account of the poorest households, which are most dependent on fisheries. The derived opportunity costs provide information about payments that are necessary to make policy interventions acceptable for different household groups.
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For a detailed specification of the class of CGE model used, see Lofgren et al. (2002).
The key modelling power of complementarity is that it chooses which inequality to satisfy as equality. Complementary slackness means that for each choice variable we must find the optimal solution that either (1) the marginal condition holds with a strict equality; or (2) the choice variable in question must take a zero value; or (3) both of the above (Bishop et al. 2001). This implies: if there is slack in a constrained resource (leftovers), then additional quantities of that resource must have no value. Likewise, if there is slack in the (shadow) price non-negativity constraint requirement (i.e. the price is not zero) then there must be scarce supplies (no leftovers).
GAMS is designed for the construction and solution of large and complex mathematical programming models. It enables solving of various kinds of economic models including linear and nonlinear optimisation as well as equilibrium modelling (Brooke et al. 1992).
The consumer bundle of the case study region includes maize, beef, milk, fish, rice, wheat, noodle, oil, potato, orange, bread, chicken, egg and non-food items.
In contrast, the Armington (1969) assumption is based on imperfect transformability and substitutability. He used constant elasticity of substitution for imports and constant elasticity of transformation for exports, which mathematically avoid a total elimination of unproductive trade flows. Hence, he did not allow any regime shifts. No country ever shifts completely from importing or exporting a commodity (Ackermann and Gallagher 2008).
This is ensured by simultaneous adjustments in three (endogenous) components of absorption: household consumption, investment quantity and government consumption. Under other investment-driven closures (value of savings adjusts), the quantities of investment and government consumption are both fixed, only household consumption is flexible (Lofgren et al. 2002).
Marginal interventions cannot be estimated reliably within the modelling system.
A SAM is a comprehensive economy-wide data framework and represents the whole economic system by explaining all payments within the economy for a single year. It plays an important role in policy planning at the regional and village level (Morton et al. 2016).
Overall robustness: the CGE results remained robust when applying an alternative production function (Cobb–Douglas).
Livelihood diversification can be defined as the process by which rural households construct a diverse portfolio of activities in order to survive and to improve their standards of living (Ellis 1998).
Ackermann, F., & Gallagher, K. P. (2008). The shrinking gains from global trade liberalization in computable general equilibrium models. International Journal of Political Economy,37(1), 50–77.
Allison, E. H. (2011). Aquaculture, fisheries, poverty and food security. Working Paper 2011-65. World Fish Center, Penang, Malaysia.
Angelsen, A. (1999). Agricultural expansion and deforestation: Modelling the impact of population, market forces and property rights. Journal of Development Economics,58, 185–218.
Armington, P. A. (1969). A theory of demand for products distinguished by place of production. International Monetary Fund Staff Papers, 16(1), 159–178.
Arndt, C., Farmer, W., Strzepek, K., & Thurlow, J. (2012). Climate change, agriculture and food security in Tanzania. Review of Development Economics,16(3), 378–393.
ATLAFCO (The Ministerial Conference on Fisheries Cooperation among African States Bordering the Atlantic Ocean) (2012). Fisheries and Aquaculture industry in Namibia. Series Report no. 2 on Fisheries and Aquaculture review in the 22 ATLAFCO member countries.
Barendse, J., Roux, D., Currie, B., Wilson, N., & Fabricius, C. (2016). A broader view of stewardship to achieve conservation and sustainability goals in South Africa. South African Journal of Science,112(5–6), 1–15.
Bartley, D. M., Funge-Smith, S., Marmulla, G., Franz, N., & Marttin, F. (2016). A valuable resource. Analysis inland fisheries, Samudra Report 74.
Belton, B., Haque, Md M, & Little, D. C. (2012). Does size matter? Reassessing the relationship between aquaculture and poverty in Bangladesh. The Journal of Development Studies,48(7), 904–922.
Belton, B., & Little, D. C. (2011). Immanent and interventionist inland Asian aquaculture development and its outcome. Development Policy Review,29(4), 459–484.
Belton, B., & Thilsted, S. H. (2014). Fisheries in transition: Food and nutrition security implications for the global South. Global Food Security,3, 59–66.
Belton, B., van Asseldonk, I. J. M., & Thilsted, S. H. (2014). Faltering fisheries and ascendant aquaculture: Implications for food and nutrition security in Bangladesh. Food Policy,44, 77–87.
Béné, C., Arthur, R., Norbury, H., Allison, E. H., Beveridge, M., Bush, S., et al. (2016). Contribution of fisheries and aquaculture to food security and poverty reduction: Assessing the current evidence. World Development,79, 177–196.
Béné, C., Hersoug, B., & Allison, E. (2010). Not by rent alone: Analyzing the pro-poor functions of small-scale fisheries in developing countries. Development Policy Review,28(3), 325–358.
Beveridge, M. C. M., Phillips, M. J., Dugan, P., & Brummett, R. (2010). Barriers to aquaculture development as a pathway to poverty alleviation and food security. Advancing the aquaculture agenda: Workshop proceedings (pp. 345–359). Paris: OECD Publishing.
Beveridge, M. C. M., Thilsted, S. H., Phillips, M. J., Metian, M., Troell, M., & Hall, S. J. (2013). Meeting the food and nutrition needs of the poor: The role of fish and the opportunities and challenges emerging from the rise of aquaculture. Journal of Fish Biology,83, 1067–1084.
Bishop, P. M., Nicholson, C. F., Pratt, J. E., & Novakovic, A. M. (2001). Tariff-rate quotas: Difficult to model or plain simple? Working Paper 2001/7. New Zealand Institute of Economic and Research.
Blythe, J. L. (2013). Social-ecological analysis of integrated agriculture-aquaculture systems in Dedza, Malawi. Environment, Development and Sustainability,15, 1143–1155.
Böhringer, C., & Rutherford, T. F. (2005). Integrating bottom–up into top–down: A mixed complementarity approach. Discussion Paper No. 05-28.
Böhringer, C., Rutherford, T. F., & Wiegard, W. (2003). Comuputable general equilibrium analysis: Opening a black box. Centre for European Economic Research. Discussion Paper No. 03-56.
Britz, W., Ferris, M., & Kuhn, A. (2013). Modeling water allocating institutions based on multiple optimization problems with equilibrium constraints. Environmental Modelling and Software,46, 196–207.
Brooke, A., Kendrick, D., & Meeraus, A. (1992). Release 2.25, GAMS, a user’s guide. San Francisco: The Scientific Press.
Carpenter, S. R., Cole, J. J., Pace, M. L., Batt, R., Brock, W. A., Cline, T., et al. (2011). Early warnings of regime shifts: A whole-ecosystem experiment. Science,332(6033), 1079–1082.
Clark, C. W. (2006). The worldwide crisis in fisheries: Economic models and human behaviour. New York: Cambridge University Press.
Colombo, G. (2010). Linking CGE and microsimulation models: A comparison of different approaches. International Journal of Microsimulation,3(1), 72–91.
Cooke, S. J., Nguyen, V. M., Arlinghaus, R., Quist, M. C., Tweddle, D., Weyl, O. L. F., et al. (2016). Sustainable inland fisheries—perspectives from the recreational, commercial and subsistence sectors from around the globe. Conservation Biology,20, 467–505.
Davies, J. B. (2009). Combining microsimulation with CGE and macro modelling for distributional analysis in developing and transition countries. International Journal of Microsimulation,2(1), 49–65.
Dervis, K., de Melo, J., & Robinson, S. (1982). General equilibrium models for development policy. New York: Cambridge University Press.
Dirkse, S. P. (1994). Robust solution of mixed complementarity problems. A thesis submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy. University of Wisconsin, Madison.
Ellis, F. (1998). Household strategies and rural livelihood diversifcation. The Journal of Development Studies,35(1), 1–38.
Fabricius, C., Koch, E., Turner, S., Magome, H., & Sisitka, L. (2013). What we have learnt from a decade of experimentation. In K. Fabricius & T. Magome (Eds.), Rights, resources and rural development—Community-based natural resource management in Southern Africa (pp. 271–281). London: Earthscan.
FAO. (2012). West African food composition table, Rome.
FAO. (2013). Global aquaculture production statistics for the YEAR 2011, Rome.
FAO. (2014). The state of world fisheries and aquaculture. Opportunities and challenges, Rome.
FAO. (2016b). FAO yearbook. Fishery and aquaculture statistics, Rome.
FAO, IFAD, & WFP. (2015). The state of food insecurity in the World, Rome.
Food and Agriculture Organization (FAO). (2016a). The state of world fisheries and aquaculture. Contributing to food security and nutrition, Rome.
Global Panel. (2015). Improved metrics and data are needed for effective food system policies in the post-2015 era. Global panel on agriculture and food systems for nutrition. London.
Government of the Republic of Namibia (GRN). (2015a). Namibia poverty mapping. Macroeconomic Planning Department,Windhoek.
GRN. (2015b). Baseline report for integrated land use planning, Zambezi Region, Namibia. Baseline Report (Vol. 1). Windhoek.
GRN. (2015c). Integrated regional land use plan for the Zambezi Region, Namibia. Land use-plan (Vol. 2). Windhoek.
GRN. (2015d). Declaration of Sikunga Channel and Kasaya Channel as Fisheries Reserves: Inland Fisheries Resources Act, 2003. Windhoek.
Gronau, S., Winter, E., & Grote, U. (2017). Modelling nature-based tourism impacts on rural development and conservation in Sikunga Conservancy, Namibia. Development Southern Africa,34(3), 276–294.
Gronau, S., Winter, E., & Grote, U. (2018). Papyrus, forest resources and rural livelihoods: A village computable general equilibrium analysis from northern Zambia. Natural Resources, 9, 268–296.
Hay, C. J., Naesje, T. F., Kapirika, S., Koekemoer, J., Strand, R., Thorstad, E. B., & Harsaker, K. (2002). Fish populations, gill net catches and gill net selectivity in the Zambezi and Chobe Rivers, Namibia, from 1997 to 2000. NINA Report 17. Trondheim.
Hazell, P. B. R., & Norton, R. D. (1986). Mathematical programming for economic analysis in agriculture. New York: Macmillan.
High Level Panel Experts (HLPE). (2014). Sustainable fisheries and aquaculture for food security and nutrition, Rome.
Hilundwa, K. T., & Teweldemedhin, M. Y. (2016). Assessing the financial viability for small scale fish farmers in Namibia. African Journal of Agricultural Research,11(32), 3046–3055.
Holden, S., & Lofgren, H. (2005). Assessing the impacts of natural resource management policy interventions with a village general equilibrium model. In B. Shiferaw, H. Ade Freeman, & S. Swinton (Eds.), Natural resource management in agriculture: Methods for assessing economic and environmental impacts (pp. 295–318). Cambridge: CABI Publishing.
International Food Policy Research Institute (IFPRI). (2016). Global hunger index. Getting to zero hunger, Washington, DC/Dublin/Bonn.
Jahan, K. M., Ahmed, M., & Belton, B. (2010). The impacts of aquaculture development on food security: Lessons from Bangladesh. Aquaculture Research,41(4), 481–495.
Jones, B., & Weaver, C. (2008). CBNRM in Namibia: Growth, trends, lessons and constraints. In H. Suich, B. Child, & A. Spenceley (Eds.), Evolution and innovation in wildlife conservation in southern Africa (pp. 223–242). London: Earthscan.
Kawarazuka, N., & Béné, C. (2010). Linking small-scale fisheries and aquaculture to household nutrition security: An overview. Food Security,2, 343–357.
Kawarazuka, N., & Béné, C. (2011). The potential role of small fish species in improving micronutrient deficiencies in developing countries: Building evidence. Public Health Nutrition,14, 1927–1938.
Klapwijk, C. J., van Wijk, M. T., Rosenstock, T. S., van Asten, P. J. A., Thornton, P. K., & Giller, K. E. (2014). Analysis of trade-offs in agricultural systems: Current status and way forward. Current Opinion in Environmental Sustainability,6, 110–115.
Kleih, U., Linton, J., Marr, A., Mactaggart, M., Naziri, D., & Orchard, J. E. (2013). Financial services for small and medium-scale aquaculture and fisheries producers. Marine Policy,37, 106–114.
Kolding, J., van Zwieten, P. A. M., & Mosepele, K. (2015). Where there is water there is fish—Small-scale inland fisheries in Africa: Dynamics and importance. A History of Water,3(3), 439–460.
Krause, G., Brugere, C., Diedrich, A., Ebeling, M. W., Ferse, S. C. A., Mikkelsen, E., et al. (2015). A revolution without people? Closing the people-policy gap in aquaculture development. Aquaculture,447, 44–55.
Layman, B., & Australia, W. (2004). CGE modelling as a tool for evaluating proposals for project assistance: A view from the trenches. In Forth biennial regional modelling workshop in Melbourne: Policy applications of regional CGE modelling, Melbourne.
Lofgren, H., Harris, R. L., & Robinson, S. (2002). A standard computable general equilibrium (CGE) model in GAMS (Vol. 5). International Food Policy Research Institute.
Loison, S. A. (2015). Rural livelihood diversification in Sub-Saharan Africa: A literature review. The Journal of Development Studies,51(9), 1125–1138.
Manning, D. T., Taylor, J. E., & Wilen, J. E. (2016). General equilibrium tragedy of the commons. Environmental and Resource Economics,69, 75–101.
McClanahan, T., Allison, E. H., & Cinner, J. E. (2015). Managing fisheries for human and food security. Fish and Fisheries,16, 79–103.
Mendelsohn, J. (2010). Atlas of Namibia: A portrait of the land and its people. Cape Town: Sunbird.
Morton, H., Winter, E., & Grote, U. (2016). Assessing natural resource management through integrated environmental and social-economic accounting. The case of a Namibian conservancy. The Journal of Environment and Development,25(4), 396–425.
Mosimane, A., & Silva, J. (2015). Local governance institutions, CBNRM, and benefit-sharing systems in Namibian conservancies. Journal of Sustainable Development,8(2), 99–112.
Muir, J. (2013). Fish, feeds, and food security. Animal Frontiers,3(1), 28–34.
Murphy, C., & Lilungwe, P. (2012). Integrated co-management of Zambezi/Chobe river fisheries resources project. Fish ranching programme in Caprivi Region, Windhoek.
Namibia Nature Foundation (NNF). (2017). Ministry makes big strides towards more sustainable inland fisheries. Media Release by the Namibia Nature Foundation, Windhoek, Namibia.
Namibian Association of CBNRM Support Organisations (NASCO). (2013). Namibia’s communal conservancies: A review of progress and challenges 2011. Windhoek.
New Partnership for Africa’s Development (NEPAD). (2005). Action plan for the development of African fisheries and aquaculture. NEPAD-fish for all summit, Abuja, Nigeria.
Nguyen, K. A. T., Jolly, C. M., Bui, C. N. P. T., & Trang, T. H. L. (2016). Aquaculture and poverty alleviation in Ben Tre Province, Vietnam. Aquaculture Economics & Management,20(1), 82–108.
NNF. (2013). GDI area proposal—CBNRM and Wetland conservation, Sikunga Conservancy, Caprivi region. Windhoek: Namibia.
Nunoo, F. K. E., Asamoah, E. K., & Osei-Asare, Y. B. (2014). Economics of aquaculture production: A case study of pond and pen culture in southern Ghana. Aquaculture Research,45, 675–688.
Parviainen, T. (2012). Role of community forestry in rural livelihood and poverty alleviation in Ohangwena and Caprivi Regions in Namibia. Academic Dissertation, 55, Helsinki.
Peichl, A. (2016). Linking microsimulation and CGE models. International Journal of Microsimulation,9(1), 167–174.
Quagrainie, K., Kaliba, A., Osewe, K., Mnembuka, B. Senkondo, E., Amisah, S., Fosu, A. K., Ngugi, C. C., & Makambo, J. (2005). Cost evaluation and benefit assessment of fish farming in selected African nations. Aquaculture collaborative research support program, twenty-third annual technical report, Oregon State University.
Rand, J., & Tarp, F. (2010). Impact of an aquaculture extension project in Bangladesh. Journal of Development Effectiveness,1(2), 130–146.
Robinson, S., Yùnez-Naude, A., Hinojosa-Ojeda, R., Lewis, J. D., & Devarajan, S. (1999). From stylized to applied models: Building multisector CGE models for policy analysis. The North American Journal of Economics and Finance,10(1), 5–38.
Röttgers, D. (2016). Conditional cooperation, context and why strong rules work—A Namibian common-pool resource experiment. Ecological Economics,129, 21–31.
Rutherford, T. F. (1995). Extension of GAMS for complementarity problems arising in applied economic analysis. Journal of Economic Dynamics and Control,19, 1299–1324.
Sowman, M., & Wynberg, R. (2014). Governance for justice and environmental sustainability: Lessons across natural resource sectors in sub-Saharan Africa. New York: Routledge.
Toufique, K. A., & Belton, B. (2014). Is aquaculture pro-poor? Empirical evidence of impacts on fish consumption in Bangladesh. World Development,64, 609–620.
Troell, M., Naylor, R. L., Metian, M., Beveridge, M., Tyedmers, P. H., Folkge, C., et al. (2014). Does aquaculture add resilience to the global food system? Proceedings of the National Academy of Sciences,111(37), 13257–13263.
Tweddle, D., Cowx, I. G., Peel, R. A., & Weyl, O. L. F. (2015). Challenges in fisheries management in the Zambezi, one of the great rivers of Africa. Fisheries Management and Ecology,22, 99–111.
United States Agency for International Development (USAID). (2016). Fishing for food security. The importance of wild fisheries for food security and nutrition, Washington.
Van Brakel, M. I., & Ross, L. G. (2011). Aquaculture development scenarios of change in fish trade and market access for the poor in Cambodia. Aquaculture Research,42(7), 931–942.
Villasante, S., Rodríguez, S. R., Molares, Y., Martínez, M., Remiro, J., García-Díez, C., et al. (2015). Are provisioning ecosystem services from rural aquaculture contributing to reduce hunger in Africa? Ecosystem Services,16, 365–377.
Waite, R., Beveridge, M., Brummett, R., Castine, S., Chaiyawannakarn, N., Kaushik, S., Mungkung, R., Nawapakpilai, S., & Phillips, M. (2014). Improving productivity and environmental performance of aquaculture. Working Paper, Installment 5 of creating a sustainable food future, Washington, DC.
Welcomme, R. L., Cowx, I. G., Coates, D., Béné, C., Funge-Smith, S., Halls, A., et al. (2010). Inland capture fisheries. Philosophical Transactions of the Royal Society,365, 2881–2896.
Weyl, O. L. F., Ribbink, A. J., & Tweddle, D. (2010). Lake Malawi: Fishes, fisheries, biodiversity, health, habitat. Aquatic Ecosystem Health & Management,13, 241–254.
WFP. (2016). WFP Namibia country brief. September 2016. Rome.
WFP. (2017a). Food aid information system, nutritional requirements. http://www.wfp.org/fais/nutritional-reporting/requirements. Accessed 15 April 2017.
WFP. (2017b). Food composition table. http://www.wfp.org/fais/nutritional-reporting/food-composition-table. Accessed 15 April 2017.
Winter, E., Faße, A., & Frohberg, K. (2015). Food security, energy equity, and the global commons: A computable village model applied to sub-Saharan Africa. Regional Environmental Change,15, 1215–1227.
WorldFish Center. (2014). Improving employment and income through development of Egypt’s aquaculture sector (IEIDEAS) project. Program Report: 2016–14, Penang, Malaysia.
This article has been written in the context of the project ‘SASSCAL—Southern African Service Science Centre for Climate Change and Adaptive Land Management’ (http://www.sasscal.org/). The project is funded by the German Ministry of Education and Research (BMBF) [01LG1201H].
Appendix A: Stylised social accounting matrix of the Sikunga Conservancy
|(A4) Fish resources||64.13|
|(A5) Forest resources||765.29|
|(A6) Off-farm employment||89.76||44.10||4.40|
|(C4) Fish resources||12.67|
|(C5) Forest resources|
|(C6) Off-farm employment|
|(C7) Food items||21.36|
|(C8) Non-food items||3.90|
|(F1) Unskilled labour||8.80||42.85||49.18||19.33||35.99||63.40|
|(F2) Skilled labour||13.85||48.28|
|(H1) Subsistence farmers|
|(H2) Fish and forest users|
|(H3) Skilled off-farm|
|(H4) Senior members|
|(S1) Cash savings|
|(S2) Agricultural capital|
|(ROW) Rest of World||41.95||4.69||9.22||10.11||0.83||21.14||69.85||70.74|
|(A4) Fish resources||1.95||8.18||0.03||1.96|
|(A5) Forest resources||25.83||20.31||5,84||4.95|
|(A6) Off-farm employment|
|(C4) Fish resources||3.39||1.68||1.06||2.13||53.30|
|(C5) Forest resources||0.24||0.07||0.06||0.46||748.98||12.65||3.67|
|(C6) Off-farm employment||7.84||4.20||3.97||5.98||32.89||39.86||11.13||5.04|
|(C7) Food items||17.45||11.39||9.51||10.14||44.10|
|(C8) Non-food items||24.45||16.11||11.59||14.69||4.40|
|(F1) Unskilled labour||27.20|
|(F2) Skilled labour||58.97|
|(H1) Subsistence farmers||76.46||14.98||5.55||3.76||1.21||9.10||17.82||0.66||12.72|
|(H2) Fish and forest users||62.66||12.68||7.70||2.48||5.15||12.31||9.00||6.41|
|(H3) Skilled off-farm||69.46||92.62||3.15||− 0.57||0.13||1.31||2.52||2.06|
|(H4) Senior members||16.62||0.81||7.67||1.56||0.20||1.88||16.54||5.28||5.87|
|(S1) Cash savings||14.86||13.02||121.76||− 20.94||51.73||11.19||− 14.85|
|(S2) Agricultural capital||14.54||20.58||6.29||12.54|
|(ROW) Rest of World||21.55||2.03||1.92||0.72||4.59||176.78|
Appendix B: Aquaculture module input data
|Requirement of a 665 m2 fish pond||References|
|Fingerlings (1000 pieces per year at 0.1 US$ each)||Murphy and Lilungwe (2012)|
|Feed (nearly 500 kg maize bran per year at 0.175 US$ per kg)||Gronau et al. (2017), Hilundwa and Teweldemedhin (2016)|
|Fertiliser (almost 600 kg manure per year at 0.75 US$ per kg)||Nunoo et al. (2014), Quagrainie et al. (2005)|
|Labour costs (clearing, feeding, harvesting, monitoring, recording) at 0.51 US$ per m2||Nunoo et al. (2014)|
|Construction (approximately 5 labourers at 3 US$ per day and 20 days) at 300 US$||Hilundwa and Teweldemedhin (2016)|
|Equipment (e.g. shovels, hooks, pick-axes, tanks/buckets, boats, wheelbarrow, fishing gear) at 150 US$ (0.075 US$ per m2)||Nunoo et al. (2014)|
|Depreciation is based on a productive life of 10 years for a pond and 3 years for the equipment (i.e. 10 and 33% respectively per year must be replaced).||Nunoo et al. (2014)|
|Land at 98.72 US$ per pond (factor value).||Own estimation|
|Fish at 0.4 US$ per kg (factor value).||Morton et al. (2016)|
|Fish at 1 US$ per kg (home consumption) and 2 US$ per kg (market sales)||Murphy and Lilungwe (2012); NNF (2013)|
|Harvesting is done once or twice a year and produces a yield of 1020 kg.||Murphy and Lilungwe (2012)|
|Per 100 g||Energy (kcal)||Fat (g)||Iodine (µg)||Iron (mg)||Protein (g)||Vitamin A (µg)||Zinc (mg)|
Appendix D: Parameters used for production, utility and biological fish growth functions
|Fish pond production function||Aggregate intermediate input coefficient||24.6||Percent||Own calculation|
|Aggregate value-added (factor) coefficient||75.4||Percent||Own calculation|
|Feed (share parameter of intermediate input use)||31.6||Percent||Own calculation|
|Fertiliser (share parameter of intermediate input use)||3.3||Percent||Own calculation|
|Fingerlings and depreciation pond and equipment (share parameter of intermediate input use)||65.1||Percent||Own calculation|
|Land (share parameter of factor use)||40.1||Percent||Own calculation|
|Labour (share parameter of factor use)||11.7||Percent||Own calculation|
|Fish (share parameter of factor use)||48.2||Percent||Own calculation|
|Utility function||Technical coefficient (ν)||0.25||Coefficient||Winter et al. (2015)|
|Wealth state of household group 1 and 2 (α and β)||0.2||Exponent||Angelsen (1999) and Winter et al. (2015)|
|Wealth state of household group 3 and 4 (α and β)||0.9||Exponent||Angelsen (1999) and Winter et al. (2015)|
|Biological fish growth function||Annual growth rate (r)||10||Percent||FAO (2013)|
|Carrying capacity in Sikunga Conservancy (Zambezi Region); yield for tropical natural fish production systems (k)||1,600,000||kg||Hay et al. (2002) and Welcomme et al. (2010)|
|Fish stock in Sikunga Conservancy (Zambezi Region) (F)||1,000,000||kg||Hay et al. (2002)|
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Gronau, S., Winter, E. & Grote, U. Aquaculture, fish resources and rural livelihoods: a village CGE analysis from Namibia’s Zambezi Region. Environ Dev Sustain 22, 615–642 (2020). https://doi.org/10.1007/s10668-018-0212-1
- Fish resources
- Rural households
- Village computable general equilibrium model