World Aquaculture - December 2014

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46 DECEMBER 2014 • WORLD AQUACULTURE •
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
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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.