By Cam McGrath
"With the initiative to increase efficiency and food production, Egypt will have to use water and land wisely to produce food," said aquaculturist Malcolm Beveridge. "It would make sense to combine aquaculture with agriculture to increase food production per unit of land and water," he explained. Currently, the possibility of adopting integrated aquaculture is being explored, which is a holistic approach to food production in which waste from commercial farming of one species is recycled as nutrients and fertilizers for another. Projects usually consist of the cultivation of several aquatic species, but the synergistic model points to greater integration with the production of fish, livestock and agricultural varieties.
"An integrated approach would be the logical next step for aquaculture in Egypt, as it could significantly lower water requirements at the same time and increase fish farmers' income," explained Beveridge. Aquaculture has experienced explosive growth in Egypt in recent decades. Annual fish production soared from 50,000 tonnes in the late 1990s to more than a million in 2013, exceeding the combined production of the other countries in Africa and the Middle East. Fish farming as mostly practiced in Egypt, simply by digging a well and filling it with water and fish, has great disadvantages. An old decree establishes that drinking water and that used for irrigation have priority in the Nile, which forces aquaculture projects to be located in the dirty waters downstream. That pollutes the fish and limits productivity. "About 90 percent of Egypt's aquaculture uses agricultural drainage water, full of pesticides, sewage liquids and industrial effluents," remarked Sherif Sadek, manager of the Cairo-based Aquaculture Consultant Office. "Why do we use the water first for agriculture and then the drainage water for aquaculture?" He asked. "It should be the other way around, first use the water for aquaculture and then to irrigate the fields," he remarked.
Integrated aquaculture reverses the water use paradigm, with tangible benefits for both fish farms and crops.
The practice is still in its infancy in Egypt, but several projects have already demonstrated its commercial viability.
At the El Keram farm, in the desert northwest of Cairo, farmers pump water to grow tilapia, then recycle it for the ponds where they raise catfish. The liquid they drain from there, rich in organic nutrients, is used to irrigate and fertilize clover fields. The goats and sheep that graze there then produce manure with which biogas is generated for heating the hatchery tanks or ponds in winter.
“The project demonstrated how farmers who opted for aquaculture when salinity rendered their land sterile can increase productivity and income, using the same volume of water,” Sadek explained.
Other integrated projects in desert lands consist of cultivating aquatic species, such as croaker and sea bream, and directing the wastewater towards ponds where they have red tilapia, which are tolerant to the high concentration of salts.
According to Sadek, the brine from these ponds is also used to grow salicornias, halophyte plants (with great tolerance to salts), highly sought after for the production of biofuel, forage and as a gourmet ingredient in salads.
"Salicornia can be watered with extremely salty water and produces seeds and oil, as well as forage for camels and sheep," he said.
Specialists ensure that integrated aquaculture offers greater efficiency and requires up to 70 percent less water than non-integrated production systems. It is also a cost-effective method of eliminating waste, as well as saving poorer farmers on the purchase of fertilizers. Beveridge said that small-scale aquaculture initiatives that cannot afford the closed systems used at El Keram can still benefit from this integrated model by allowing them to harvest commercial products year-round. "Aquaculture in Egypt has the problem that the vegetative period is relatively short," he said. Between December and February, temperatures are too low to support fish growth. Farmers who try to hibernate often lose large numbers of animals to stress and disease, he said. Pilot studies have shown that fish farmers can capitalize on the nutrients that accumulate in the mud that covers the bottom of the ponds where the fish are raised.
“The idea is that you empty the ponds in November, collect your fish, and then grow wheat on their bottom, which will be harvested in March, before refilling the stubble area with water and putting the juvenile fish in it,” he explained. Beveridge.
Translated by Verónica Firme