46 DECEMBER 2014 • WORLD AQUACULTURE • WWW.WAS.ORG for salmonids, diadromous fish and cage culture was subtracted. Assuming an average feed conversion ratio (FCR) for salmonids and other diadromous fishes of 1.2 (Marine Harvest 2013) and that the production of these fish totaled 3.73 million t (FAO 2011), 4.48 million t of feed were consumed by these species. Cage culture production was 3.4 million t in 2005 (Tacon and Halwart 2007), but this production included salmonids and diadromous fish. Thus, cage culture production of other species probably was around 1.1 million t. At a typical FCR of 1.75 (Beveridge 1993), 1.92 million t of feed were consumed by fish in cages. Subtracting the total feed used for salmonids, diadromous fishes, and other cage culture species (6.3 t) is from the total aquaculture feed production, suggests that 27.6 t were used for pond aquaculture. Multiplying the amount of feed used in pond aquaculture by the average land area required for plant meals for feed (0.274 ha/t), around 7.6 million ha of land were used for producing plant-based feed ingredients for feed applied to aquaculture ponds. Adding the land for plant crop production (7.6 million ha) to the adjusted water surface area and support area required for farms estimated above (24.8 million ha), indicates that about 32.4 million ha of land are dedicated to pond aquaculture. The production of non-pond fish that was removed before calculating land use for plant feed ingredients for pond aquaculture also requires land for feed. Even cage culture in natural lakes requires land to support production in cages. Global Implications The estimates of pond water surface (Verdegem and Bosma 2009) and the land to water ratios and area needed for plant ingredients are subject to considerable uncertainty. However, even if estimates are 25 to 50 percent too low, aquaculture still uses a very small area of land compared to world agriculture usage of 4,920 million ha (Boyd et al. 2013). Although aquaculture is probably not a major land use in any country, it can bring significant changes to the landscape, redirect other land uses and cause ecological problems. As aquaculture production increases in the coming years, so will production from terrestrial agriculture. Thus, despite having a small impact of total land use at present and in the future compared to terrestrial agriculture, pond aquaculture is and will continue to be of vital importance to the food security of many developing countries, and an important component of the world food system. Ecolabel certification is becoming more popular among farmers as the demand for such products increases. These certification programs have specific standards intended to avoid negative environmental impacts, but they also are used to make farms more efficient in feed, energy, and water use (Boyd et al. 2013). Certification standards could be extended to include a standard related to the maximum allowable land to water surface area ratio. The standards for ecolabel certification typically require farmers to improve on current management practices. The standard for land to water surface area ratio would no doubt be less than the average found by this survey. Notes Lauren N. Jescovitch and Claude E. Boyd, School of Fisheries, Aquaculture and Aquatic Sciences Philip Chaney, Department of Geology Auburn University, Auburn, Alabama 36849 USA 1 www.fao.org/fishery/statistics/en 2 faostat.fao.org 3 www.alltech.com/sites/default/files/2013-feed-tonnage-report.pdf References Alonso-Perez, F., A. Ruiz-Luna, J. Turner, C.A. Berlanga-Robles and G. Mitchelson-Jacob. 2003. Land cover changes and impact of shrimp aquaculture on the landscape in the Ocean and Coastal Management 46:583-600. Beveridge, M.C.M. 1993. Cage and pen fish farming: Carrying capacity models and environmental impact. FAO Fisheries Technical Paper 255. FAO, Rome, Italy. Boyd, C.E. and M. Polioudakis. 2006. Land use for aquaculture production. Global Aquaculture Advocate 9(2):64-65. Boyd, C.E. and J. L. Shelton, Jr. 1984. Observations on the hydrology and morphometry of ponds on the Auburn University Fisheries Research Unit. Bulletin 558, Alabama Agricultural Experiment Station, Auburn University, Alabama, USA. Boyd, C.E., J. Queiroz and A.A. McNevin. 2013. Perspectives on the responsible aquaculture movement. World Aquaculture 44(4):14-21. FAO (Food and Agriculture Organization of the United Nations). 2011. Yearbook of Fisheries Statistics, Summary Tables: Aquaculture Production 2011. Giap, D. H., Y. Yi and A. Yakupitiyage. 2005. GIS for land evaluation for shrimp farming in Haiphong of Vietnam. Ocean and Coastal Management 48:51-63. Green, E.P., P.J. Mumby, A.J. Edwards and C.D. Clark. 1996. A review of remote sensing for the assessment and management of tropical coastal resources. Coastal Management 24:1-40. Marine Harvest. 2013. Salmon Farming Industry Handbook 2013. Bergen, Norway. hugin.info/209/R/1698446/559980.pdf . Sapkota, A., A. R. Sapkota, M. Kucharski, J. Burke, S. McKenzie, P. Walker and R. Lawrence. 2008. Aquaculture practices and potential human health risks: Current knowledge and future priorities. Environment International 34:1215-1226. Tacon, A.G.J. and M. Halwart. 2007. Cage aquaculture: a global overview. FAO Fisheries Technical Paper 498. FAO, Rome, Italy. Verdegem, M.C.J. and R.H. Bosma. 2009. Water withdrawal for brackish and inland aquaculture, and options to produce more fish in ponds with present water use. Water Policy (Supplement 1) 11:52-68. On intensive farms, ponds tend to be smaller than on extensive and semi-intensive farms, and this means a relatively greater area for roads and canals on intensive farms. The intensity of pond aquaculture has been increasing as better management practices were developed and implemented.
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