Tilapia Culture in NEGEV, The Israeli Desert*
1YAFIT (R&D) Laboratory, Fish Breeding Center, Gan
Shmuel 38810, Israel.
2Israel Ministry of Agriculture, Aquaculture Division,
Aquaculture Extension Officer.
3Israel Maritime College, Michmoret 40297, Israel.
desert, the southern part of Israel, covers more than 50% of the total country
area. Since the state of Israeli was established (1948), the governmental
authorities have seriously considered that Negev has high potency for future Israeli settlement plans,
and extreme importance for settling thousands of immigrants, arriving in Israel
after the Holocaust in Europe. The government planned to settle-down small
settlements, like kibbutz or collective villages that can be based on
sophisticated and intensive agriculture, and clustered around several urban
centers. Hydro-geological surveys, initiated soon
after the state has been established, have revealed that the Negev and its eastern part, the Arava valley, possess tremendous amounts of
saline underground and geothermal waters. Although the water contains variable
salt concentrations, it can be utilized for integrated agriculture, e.g.
irrigation of agricultural crops combined with intensive aquaculture. At present
great parts of Negev have been converted into areas of green agriculture, where fruits
and vegetables are successfully grown. In spite of economical constraints, the
fishculture industry in Negev has positive tendency of development.
More than 10 super-intensive fish farms
have been constructed in various parts of Negev, where the geothermal water is passing
through fish culture raceways, and then used for irrigation of crops. The
tilapia is one of the most promising species, among other exotic fish (ornamental
and edible) species that are presently cultured in Negev aquaculture. In order to achieve fast
growing fish, most of the tilapias are either, sex-reversed males derived from
crosses between Oreochromis niloticus and O. aureus, or sex-reversed red tilapias. Due to
suitable climate and plenty of warm underground water, the tilapias are
continuously grown, round-year, to marketable size of 500-700 grams in 6-8
months, in biomass extending the densities of 20-27 kg/m3.
*pp. 60-65 in: R.D. Guerrero III and R. Guerrero-del
Castillo (eds.) Tilapia Farming in the 21st Century
(Proceedings of the International Forum on Tilapia
Farming in the 21st Century, Tilapia Forum 2002)
NEGEV, THE ISRAELI DESERT
The Ottoman rulers, followed by the British Mandatory
authorities (1918-1948), considered the Israeli Negev desert as an uninhabitable territory whose main
importance was strategic and political. They invested only limited efforts in
developing the region and improving the standard of living of Bedouins, at that
times the only inhabitants of Negev. At present, though the Israeli desert extends over 2/3 of the country, it is inhabited by less than 10% of
Although the State of Israel borders the Mediterranean Sea,
its climate is profoundly affected by the proximity of vast deserts (Sinai and
Arabian) to the south and east. Precipitation is limited to the winter season
(400 and 800 mm north to Beer-Sheba), which extends essentially from November
to March, and declines sharply toward the south and east, dropping almost to
zero. Thus, Israel is characterized as semiarid, and the Negev
region, which extends over more than 50% of the
country, is classed as arid and needs to be irrigated all year round to sustain
agriculture (Fig. 1). Even where
precipitation is relatively high - in the northern and western parts of Israel
- summer crops require irrigation between April and October. Stronger solar
radiation, extreme temperatures (Fig. 2)
and higher levels of water evaporation from the ground surface characterize the
more aridic areas.
Fig. 1. The NEGEV desert, in the southern
part of Israel.
Beneath this desert are huge aquifers containing extremely large
quantities of fossilized and geothermal water, either fresh or saline. The
research detected tremendous amounts of water, stored millions of years ago in
an underground reservoir, the largest underground high-quality fresh water
lakes existing in Israel. In close neighborhood to these lakes are brackish and
geothermic (Ĺ400C) waters trapped in separate pockets. These waters
cannot be replenished. Hydro-geological surveys have
revealed that the Negev and its neighboring Arava valley possess considerable reserves of
saline underground water with a variable concentration of salts. For the last 30 years the brackish water has been
successfully used for irrigation of agricultural crops (e.g., tomatoes,
water-melons, graves, jojoba, olives, etc.). At the beginning of 1970's Israel
started investigation of hydrology in the Negev, the arid and the semi-arid part of Israel (Issar et
al., 1983). Presence of water in this region has been incorporated into
national plans of population distribution and agricultural development. The
hydrologists estimate that billions cubic meters of water are stored
underground, which can be exploited during hundreds of years, supplying demand
of the growing population and agricultural development. From the very inception of modern Israel, settling the desert and
turning it into farming land was considered a matter of national priority.
First by trial and error and later on followed by research and development,
agricultural know-how was incorporated into practice and became a highly useful
tool for turning the desert into productive and habitable land.
Monthly minimum-maximum average temperatures of air and water at EinYahav tilapia farm,
during the winter season (ARAVA Valley - NEGEV Desert).
AQUACULTURE IN DESERT
plateau highlands are a district in the Israeli desert with a community of
about 5000 inhabitants, which currently use about 4.5-million m3
brackish water per annum, for agriculture-aquaculture purposes. These demand is
supplied by means of several wells, at the depth of 550-1000m, equipped with
separate pip-lines, supplying brackish-water at the salinity of 2680-4360 TDS
and high quality fresh-water (at 39-41ÂˇC)
Fig. 3. A model of multiple and integrated utilization of brackish
and geothermal water in Negev.
In the past ten years, investigations have shown the
significant potential of the geothermal, brackish water for the successful
culture of aquatic organisms (fish, crustaceans, algae, etc.). In order to
improve the economic viability of both sectors - aquaculture and agriculture -
it is obvious that a chain of users of the desert water is indispensable. A
practicable, efficient chain of users is illustrated in Fig. 3.
IsraelĂ•s semi-arid climate, in which water is
a scarce commodity, required the development of an intensive form of
aquaculture. In the Negev,
brackish water allows its application only for limited agricultural purposes.
Therefore, advanced technologies are employed to make maximum use of every
cubic meter of water.
Impressive yields have been achieved recently using
all-plastic Ă”bubbleĂ• tanks. Through the entire arid Negev and Arava region, in which air and water temperatures are kept constant
throughout the year, yields have been up to 35 times higher than those of
fish grown in subtropics in conventional outdoor ponds, and have been achieved
in half the growing cycle.
ADVANTAGES OF DESERT AQUACULTURE
the paradoxical context - aquaculture in desert - several clear and
significant advantages in development of tilapia aquaculture in Negev desert
have been defined at planning:
Exploitation of brackish
water, incompetent for utilization in routine methods of "green" agriculture.
protection of crops (and fish) grown in greenhouses, allow suitable control of
optimal temperature levels, due to high temperatures and intensive solar
irradiation, existing in desert, almost all year around.
Availability of warm
geothermal water, which permits optimal temperature levels, during the extreme,
although short, cold winter season, existing in the desert.
Extreme dry climate that
facilitates cooling of geothermal water during hot summer, by strong
Abundant low-cost land.
Presence of high-level
which facilitates possibility of adequate animal quarantine husbandry.
Possibility of culturing
aquatic organisms without endangering ecological systems or environmental
Possibility of growing
highly priced off-season fish, vegetables and fruits.
Round year fish
THE PROGRESS OF TILAPIA CULTURE METHODS IN NEGEV
Tilapia growth-rates and disease resistance decline at
temperatures lower than 200C. Unfortunately; fish farming in Israel
faces the problems of low temperatures during five months of the year. In order
to keep tilapia alive, development of an over-wintering storage systems become
a must. Such systems require relatively high investments in order to support
fish with optimal surviving conditions at cold winter. For instance, plastic
covered structures have been constructed over fishponds to maintain optimum
water temperatures during the course of commercial scale fish growth. Several
types of tanks, and methods of polyvinyl coverage have been recently examined:
A metal frame greenhouse (with special anti-corrosive treatment of the metal
piping), the "Aquabubble" (a frameless inflated plastic cover made of
net-reinforced PVC), and other shapes such as the "Igloo" or
"Tent" are set up similarly. The cover material selectively blocks
infrared radiation escaping from the pond, thus reducing heat loss, while
allowing the sun's rays to pass through and warm the pond during the day.
production strategies used for culturing of tilapia in Negev, have been changed and improved with time.
At the beginning a simple "flow-through"
system was used for culturing tilapia. In this system, large volumes of water
continually passed through the fish growing compartments, flushing out
suspended solids and harmful nitrogenous wastes. Such system was efficient in
summer, when the final user (agriculture) needed plenty of fertilizers and
water for irrigation of crops. However, at winter, when agricultural demand for
water decrease (due to low irrigation levels), excessive amount of water was
disadvantageous. As consequence, water recirculation systems were developed,
which involved bio-filtration and removal of solid-wastes, to maintain optimal
quality of water (reviewed by Avnimelech, 1998). In such systems the daily water
exchange rates for fresh as well as for brackish water can vary between 5% and
In order to maintain optimal oxygen concentration in
the super-intensively stocked tilapia ponds, all farms are equipped with
mechanical paddle-wheel aerators and/or venturi air-aspirators. The solid and
suspended particles in culture tanks are biologically treated by means of
aerobic nitrification and flocks of bacteria. Usually such systems are also
supported with a trickle-filter, comprised of polystyrene particles or other
inert substrates, characterized by large surface, on which nitrifying bacteria
form thin films, improving oxidation of ammonia to nitrate. The commercial fish
farmers continue to improve the bio-filtration methods. Fluidized beds and
trickling filters undergo additional refinements to maintain good water
Fig. 4. Tilapia farms in
With addition to the mentioned above, experimental
pilot projects involving hydroponics bio-filtration carried out at the "Desert
Aquaculture Research Station",
indicate that application of sophisticated filtration methods into the existing
bio-filters can largely improve and sustain the quality of water. Such
improvement permitted integration of aquaculture and agriculture, ("dual
cropping"), whereby herbs and vegetables could become an additional income
as by-product of aquaculture.
Skilled personnel and superior management abilities
are indispensable prerequisites for production of average annual yield between
20 and 27 kg/m3 of fish. Data collected from four model farms in the
Negev and Arava region have shown promising yields and profits. The
fish growers, owners of the model farms, who started with total yields of 30-50
tons/annum, decided to expand their production, in order to reach average
annual yields of 100-150 tons, with financial assistance of the Israeli
Ministry of Agriculture.
Tilapia management in the desert involves all
conventional stages known in tilapia culture. Fish are produced either by
crossing females Oreochromis niloticus with males O. aureus, or spawning of red tilapia. The fry produced in
spawning ponds are sex-reversed by means of male-hormones. Then the fry are
nursed in intensive nursing ponds, where they are grown to fingerlings of 5
grams. The fingerlings are transferred to rearing ponds where they reach the
size of 80-120 grams. At this size, the tilapias are transferred to fattening
ponds, where the fish are grown to the marketable size of 500-700 grams.
Due to suitable climatic conditions and availability
of huge reservoirs of underground geothermal water, the fish are continuously
round-year produced, which enables permanent and reliable supply of fish supply
to the markets.
Avnimelech, Y. (1998). Minimal discharge from intensive fish
ponds. World Aquaculture, 2:32-37.
Issar, A., Oron, G. and Porath, D.
(1983). Warm brackish groundwater as a source of supply for integrated projects
of root zone warming, aquaculture, irrigation and recreation projects. Pp.
105-115 in: L. Fishelson and Z. Yaron (comp.). Proceedings of International
Symposium on Tilapia in Aquaculture.
Tel Aviv University, Tel Aviv, Israel. 624 pp.
Pruginin, Y., Fishelson, L. and Koren,
A. (1988). Intensive tilapia farming in brackish water from an Israeli desert
aquifer. Pp. 75-81 in: R.S.V.
Pullin, T. Bhukaswan, K. Tonguthai and J.L. Maclean (eds.). The 2nd
International Symposium on Tilapia in Aquaculture. ICLARM Conference Proceedings 15. Dept. of Fisheries,
Bangkok, Thailand and ICLARM, Manila, Philippines. 623 pp.