Aquaculture success stories in Southern Africa

There are not too many successful commercial aquaculture enterprises in Southern Africa, but these two are worth mentioning.

Aquaculture success stories in Southern Africa
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To celebrate my 60th aquaculture column, it seems appropriate to feature two success stories from the Southern African warm water fish farming industry. While there are many small, productive systems around, successful commercial-scale ventures are few and far between.

Eastern Cape Tilapia
Eastern Cape Tilapia near Port Alfred was started by Stephen Maartens and Gordon Milne in 2013, and now has seven grow-out tunnels, one fry rearing system and one filtration tunnel. There are 14 large, rectangular grow-out tanks – all self-cleaning – and each stocked with 4 000 red tilapia. Further expansion will include a fish-processing factory as well as feed manufacturing.
The scale of water filtration is the key to success.

The operation has one large gravity-fed filter that uses simple, tried-and-tested technology. Gravity-settlement sedimentation tanks remove sediment without any machinery or electrical devices. Flushing is as straightforward as opening a valve every day to remove solid waste to a sump, to be disposed later.

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The total volume of the filter is far greater than the recommended 30% grow-out volume of 1,29 million litres, and could accommodate a reserve capacity if required. Water is supplied from a quarry-fed stream using gravity, as well as from a strong borehole. The set-up is everything a good recirculating aquaculture system (RAS) should be: uncomplicated, user-friendly and well-built.

Eastern Cape Tilapia currently uses only one strain of male red O. mossambicus. They are bought in at 30mm in size and reared in the nursery to 50mm before stocking. Using the best strains of red Nile tilapia in future would undoubtedly improve the farm’s profitability. Consumers are familiar with marine fish and prefer the red varieties of these. Red tilapia strongly resemble red marine species in both appearance and flesh quality.

Peixe bela vista
Peixe Bela Vista, a large-scale pond farm 42km from Maputo in southern Mozambique, was established in 2013. The climate is similar to that of northern KZN or Musina in Limpopo. A major strength of the enterprise is that it is combined with an intensive poultry operation, which provides plenty of chicken manure. This is added to the ponds to allow zooplankton and phytoplankton – natural fish food – to flourish. No commercial pelletised feed is used, and running costs are therefore low.

The ponds are each 0,5ha in size and stocked with male tilapia to avoid precocious breeding in the ponds. A newly-built hatchery uses tunnel technology, hapa nets and biofiltration of the warm water, to allow year-round breeding. As with Eastern Cape Tilapia, the hatchery’s filtration is extensive yet simple, resulting in an efficient, problem-free operation.

The tilapia are currently nearing market-size and newly-installed processing and refrigeration facilities will allow the harvested stock to be stored, ready for the market. The 26 flooded ponds, and another 26 ponds under construction, will ensure production of about 5t/ha/year. There is no reason that similar projects could not be established in the warmer regions of South Africa.

Nicholas James is an ichthyologist and hatchery owner.