Bioeconomic feasibility of aquaponics in South Africa: leapfrogging for sustainable development of freshwater aquaculture.
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Date
2020
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Abstract
Food security is being threatened globally due to a combination of factors, such as climate
change, anthropogenic pressures and burgeoning competition for limited water and land
resources. The need to adopt environmentally and economically sound sustainable food
production systems which are adaptable to the prevailing environmental stressors is
imperative. Aquaponics sustainably converts aquaculture waste into nutrients for plant
uptake resulting in an unconventional food production system which potentially provides
an economically viable means of food production. Integrated recirculating aquaculture as
adaptive technology is complex and capital intensive, thus, must be financially
sustainable. This study, therefore, assessed the bioeconomic feasibility of aquaponics (a
branch of aquaculture) in South Africa as a potential leapfrog technology for the rapid
development of aquaculture, attainment of food security and local economic
development. Quantitative and qualitative SWOT analyses, and key success factors of
leading aquaculture players in Africa (Egypt, Nigeria and Uganda) were used as a
benchmark to assess the South African aquaculture sector.
Qualitative analysis of South African aquaculture sector vis-à-vis the leading aquaculture
players in Africa reveals a suboptimal environment that is not suitable to drive costeffective
and competitive conventional large-scale commercial aquaculture. Also,
inadequate enabling environment due to bureaucratic hindrances towards the
implementation of well-crafted aquaculture development policies and framework, and
higher operating cost were identified.
The quantitative SWOT analysis of key aquaculture players in Africa revealed Egypt was
having the highest aquaculture development competitive strengths, and Nigeria showed the highest aquaculture development and market opportunities. Quantitative SWOT
analysis of key aquaculture species in South Africa showed trout and tilapia have the
highest competitive strengths, while abalone, oyster and marron crayfish showed good
market opportunities but weak in competitive strengths.
Growth performance of Oreochromis mossambicus and the yields from plants – tomato,
pepper and cucumber due to the effects of plant density and stem pruning were assessed
in a twin system designed, constructed and operationalized as a low-cost, small-scale
aquaponic system. The economic viability of the aquaponic system was assessed using
the price trend analysis of fresh produce in South Africa, biomass yield, cost inputs and
revenue models using conventional aquaponic cultural methods. Financial performance
was determined using financial metrics such as return on investment (ROI), net present
value (NPV), internal rate of return (IRR) and profitability. Analyses were modelled to
determine the financial performance of the aquaponic system.
The growth performance and yield of fish cultured in the aquaponic system showed
excellent performance based on FCR (1.25 %), survival rate (97.5 %), LWR r2 (0.945),
regression coefficient b (3.1) and condition factor K (1.93). Total and marketable yield of
vegetables (tomato, sweet pepper and cucumber) significantly increased (p < 0.05) with
a higher plant density of 8 plants /m2 compared to 5 plants/m2. Plants with a higher stem
pruning to two and three stems performed significantly better than those pruned to one
stem (p < 0.05). The interactive effects of a higher plant density and stem pruning resulted
in significant (p < 0.05) higher total and marketable yields with all the plants. Economic
analysis of the small-scale aquaponic setup and operation did not present economic
feasibility with the adoption of conventional cultural techniques (a revenue model of 59:41 % fish to plant ratio) as a result of the higher operating cost associated with fish
production. A fish to plant revenue model of 42 : 58 % ratio (achieved by adopting
optimized cultural technique) however, showed marginal economic viability. Plant yield in
aquaponics can be improved for higher economic returns through the synergistic
optimization of plant density and stem pruning while adopting other optimal cultural
management practices. A minimum revenue model of 30 : 70 % fish to plant ratio is
recommended for aquaponic operations in South Africa to attain economic feasibility.
Aquaponics thus presents optimistic potential to drive sustainable and feasible food
production in South Africa with the adoption of viable production and marketing
strategies.
Description
Doctoral Degree. University of KwaZulu-Natal, Durban.