Although the engineering described in this article, and the low level of environmental impact it causes, is from a farm in Saudi Arabia, it is suited to all coastal low plains. It could be adapted easily to sites around the Mediterranean sea, as the coastal areas of South East Turkey: Tasucu lagoon and river delta, Adana province, and the entire area south of Iskanderun, between Ulçinar and the Orontes River mouth.

A new type of coastal shrimp farm, the first full size commercial shrimp farm of the Middle-East was tested and developed on the shores of the Red Sea coast of Saudi Arabia. The main concern of Dr Nasser, then the managing director of Saudi Fisheries Company, was the pollution that he had observed in Asian shrimp farms.

The challenge was thus to re-invent shrimp farming. The concept sprang from trials in a small pond and a makeshift hatchery under a beach tent. It developed first into the design of a pilot farm of 3 hectares before being extended into a full size commercial farm with an output of more than 1,500 tonnes per year. The constant quest for the healthiest living conditions for the shrimps has led the way to the realisation of a new kind of shrimp farm, characterised by its optimal sustainability and its consideration of the environment.

Design, engineering & hydraulics

In 18 months, 228 hectares of ponds were built, comprising 108 hectares of culture ponds. It accounted for 2.5 million cubic metres of earthworks and 26,000 cubic metres of reinforced concrete. The high standard of engineering was realised in close collaboration with civil engineers, from Turkey and Belgium, with specialised experience in earth dams, in sea port civil structures and in complicated urban sewerage systems.

The concept was based on common sense. Experienced aquaculturists learn a simple lesson: the best hydraulics are “bathroom hydraulics”. The best design of aquaculture is in our bathroom: first, we need a lot of water! Second, the hydraulics are strict: there must be an inlet and an outlet, the inlet must be higher than the outlet, and they should not mix. Unhappily this common sense rule is only too rarely respected in aquaculture farm design.

When amateur entrepreneurs build shrimp farms in soft coastal low lands with typical high water-table, they attempt to realise a balance between excavating and backfilling and they create the worst possible mixing of waters. The used waters, loaded with organic matter, get direct access to the underground water table where it rapidly pollutes the entire water environment.

It is one of the obvious sources of most sanitary problems which plague today the world shrimp farming.

In order to respect this principle of an abundant open flow of sea water, civil engineers on the Red Sea farm have designed a gravity flow system without any stagnant water nor mixing of used waters with the water table. The construction technology used floating foundations and monitored settlement of the earthworks. It avoided all excavation: the network of dams and dikes was built on top of the impervious layer, from clay and sand borrowed from other parts of the site.
The application of such strict hydraulics has led to what is today maybe the cleanest and most sustainable large size commercial shrimp farm.

Green water management produces healthy shrimps and clean effluents

Culture ponds of 1 hectare each are round with central drainage and strong whirl current from well positioned aerators. 120 hectares of large and deep upstream buffer-ponds and downstream shallow ponds for treatment of the effluents double the water surface.

The upstream buffer-ponds are especially important: they are fertilised and supply the culture ponds with a constant flow of pre-bloomed green water. This guarantees the stability of the shrimp milieu in the culture ponds.

Furthermore, by allowing the warming-up of the sea-water under the sun during the storage in the buffer-ponds, the technology allows for shrimp farming of marketable tropical species to extend to the Mediterranean coasts with at least one full summer crop and corresponding profitability.

The fine tuning of the system allows for self-cleaning action of the whirl current: up to 20 weeks of culture with no crash of the algae bloom and almost no organic deposit on the pond bottom. Full strength sea water and green water management offer the shrimps a very stable and healthy environment. As a direct consequence, shrimps show no sign of stress, very regular feeding habits, homogenous sizes, perfect shape and cleanness at harvest. The final effluents drained to the sea are clean. Sustainability is maximum and is the very means to higher quality products. Regularity and reliability of quality and quantities allow for marketing contracts on de-luxe segments of the market, which, in turn, mean higher profits.

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