When aquaculture projects struggle to meet expectations, the cause is often traced back to feed, seed quality, or farm management. Yet, in practice, many challenges originate much earlier in the decision-making process. Site selection is one of the most consequential choices a farm makes, shaping biological performance, operational cost, and long-term resilience.
In the African context, where environmental variability, infrastructure gaps, and regulatory complexity are common, site selection is not a technical checkbox exercise. It is a strategic decision that determines whether a farm is working with its environment or constantly compensating for it.
This article focuses primarily on freshwater systems, which dominate aquaculture production across the continent, with particular attention to pond and cage-based systems. A short section on marine and brackish water sites is included to highlight key contrasts.
Why Site Selection Matters More Than it Appears
A well-chosen site reduces risk before the first fish is stocked. It influences water availability and quality, temperature stability, disease exposure, logistics, labour access, and operating costs. Poor site selection, by contrast, locks farms into permanent mitigation mode, relying on additional inputs, labour, or infrastructure to compensate for avoidable constraints.
In many African projects, site selection decisions are driven by land availability rather than suitability. While this is understandable, especially for smallholders or emerging farmers, it increases the importance of understanding trade-offs and constraints from the outset.
Freshwater Aquaculture in Africa:
Dominant Systems and Site Implications
Freshwater aquaculture in Africa is dominated by tilapia and catfish production, with systems ranging from small earthen ponds to large cage arrays on lakes and reservoirs. Each system places different demands on site conditions.
Pond-based Systems:
Working with Land and Water Together
Earthen ponds remain the most widespread freshwater production system across Africa due to their relative simplicity and scalability. However, not all land that can hold water is suitable for productive aquaculture.
Key site considerations for ponds
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Water availability and reliability
Ponds require a dependable water source throughout the production cycle. Seasonal rivers, rainfall-dependent filling, or shared irrigation canals introduce risk unless carefully managed. Farmers should assess not only average water availability, but also dry-season minima.
Soil characteristics
Clay or clay-loam soils reduce seepage losses and construction costs. Sandy soils may require liners or compaction, increasing capital and maintenance requirements.
Topography and drainage
Gently sloping land supports gravity-fed filling and drainage, reducing energy costs. Poor drainage increases flood risk and complicates harvesting.
Water quality baseline
Temperature range, turbidity, and nutrient load influence growth and health. Sites downstream of agricultural or urban runoff require careful evaluation.
Biosecurity exposure
Shared water sources increase disease risk. Sites that allow some level of water control and isolation offer long-term advantages.
Pond sites that appear cheaper at acquisition often carry hidden costs through pumping, repairs, or disease management. A conservative assessment upfront usually proves more economical over time.
Cage-based Freshwater Systems:
The Environment as Infrastructure
Cage farming in lakes and reservoirs has expanded rapidly across parts of East and Southern Africa. In these systems, the water body itself becomes the primary infrastructure, shifting site selection priorities.
Key site considerations for cages
Water depth and circulation
Adequate depth supports waste dispersion and reduces benthic impacts. Consistent water movement improves oxygen availability but must remain within tolerable limits for fish and structures.
Wind and wave exposure
Moderate wind supports mixing, but excessive exposure increases structural stress and operational risk. Seasonal wind patterns should be assessed, not just average conditions.
Water quality stability
Large water bodies can buffer temperature and chemistry, but stratification, algal blooms, or low-oxygen events still occur. Historical data and local knowledge are valuable here.
Navigation and competing uses
Fishing activity, transport routes, and community access affect both safety and social licence. Sites must be technically suitable and socially workable.
Regulatory clarity
Permitting frameworks for cages vary widely across countries. Secure tenure and clear regulatory status reduce long-term uncertainty.
Cage systems can achieve high productivity, but only when site conditions support consistent water exchange and manageable risk exposure.
Comparing Pond and Cage Sites: Different Risks, Different Controls
Pond systems offer greater environmental control but higher dependence on land and water management. Cage systems benefit from natural water exchange but expose farms to broader environmental and social dynamics. Neither system is inherently superior. Success depends on alignment between site characteristics, farmer capacity, and production objectives.
A Brief Note on Brackish and Marine Sites
While freshwater systems dominate African aquaculture, brackish and marine farming is growing in selected coastal regions. Site selection here adds additional layers of complexity.
Key considerations include salinity stability, tidal range, current velocity, storm exposure, and corrosion risk. Coastal land tenure, environmental permitting, and competing economic activities often play a larger role than in inland systems.
Marine sites offer strong growth potential but demand higher upfront assessment and more robust operational systems.
Site Selection as a Long-Term Commitment
Once infrastructure is in place, relocating a farm is rarely feasible. Site constraints therefore shape every subsequent management decision. In practice, many farms succeed not because they chose a perfect site, but because they understood its limitations and planned accordingly.
The most resilient projects treat site selection as an iterative process. They combine technical assessment, local knowledge, seasonal observation, and conservative assumptions. They also recognise that what matters is not only biological suitability, but operational and social context.
Closing Reflection
Site selection is not simply about where fish can survive. It is about where farming systems can function efficiently, adapt to change, and grow sustainably. In African aquaculture, where variability is the norm rather than the exception, thoughtful site selection remains one of the strongest foundations a farm can build.
For those interested in revisiting the fundamentals of system design and environmental interaction, the Basics of Aquaculture Management course on ACMS InDepth offers a structured way to think through these decisions step by step.
The most resilient projects treat site selection as an iterative process. They combine technical assessment, local knowledge, seasonal observation, and conservative assumptions. They also recognise that what matters is not only biological suitability, but operational and social context.