2. AQUACULTURE

2.1 GENERAL

The total fish production from aquaculture in Syria in 1981 was 982 t, corresponding to 23% of the total capture fisheries (4 282 t) and to 29% of total freshwater fishery (3 359 t).

For 1982, the General Establishment of Fisheries (GEF) predicted an increase in its aquaculture production of 79.4%; of 48.3% for the freshwater fishery and 48.4% for the marine fishery (Table 1).

The GEF justifies the increase as due to improved technology; no additional fish-farms have been established. At present, the GEF has 10 plants of which 9 are main fish-farms (2 producing trout and 7 carp and tilapia) and one producing carp with floating net cages. These plants are divided into 5 of the 6 branches of the GEF, each relative to a geographical area and each with a director (Table 2 and Figure 1).

They cover a total surface of about 300 ha of which almost 250 ha of water, with a total water supply of about 2.5 m³/sec (Table 3)¹.

¹ All data are derived from interviews with the plant directors and their staff. Different information was obtained on the same subject from different sources. Figures reported here appeared the most realistic.

Table 1

CATCHES FOR 1981 AND ESTIMATED CATCHES FOR 1982

Table 2

ORGANIZATION OF THE GENERAL
ESTABLISHMENT OF FISHERIES

¹ Reservoirs

Table 3

CHARACTERISTICS OF THE PLANTS

Table 3 shows structural characteristics of the plants as well as the species reared and production during 1981 and that planned for 1982. The total production of 1981 differs from that declared by GEF (Table 1) because some production (e.g., Nib Al Sin) is over a 2-year period (1980 and 1981), and for others (Ain Al Taka) it is only nominal. To the planned production for 1982 must be added 55 t of carp from the dams (Jarine, Sha Raba Dam and Homs Dam). A detailed description of the 1982 planned production for aquaculture is reported in Table 4.

Table 4

PLANNED AQUACULTURE PRODUCTION FOR 1982

2.2 DAMASCUS BRANCH

2.2.1 Zabadani Fish-Farm

2.2.1.1. General

The farm is located in the hills near Lebanon, 45 km northwest of Damascus, at about 1 150 m above mean sea level. It has a total surface of about 6 ha, of which about 0.5 ha of water. The main activity is the production of trout fingerling for all the other trout farms; and second, a limited production of market size trout (Salmo gairdneri).

2.2.1.2 Facilities

(Figure 2)

The farm consists of:

A hatchery: in a building of about 400 m² (Figure 2 [2]) containing:

• 50 fibreglass Californian troughs (4 × 0.6 m) with 6 boxes each (0.4 × 0.4 m)
• 20 glass Zugg jars of about 10–1 capacity
• 1 plastic and aluminium incubation case (new)

The total contemporary hatching capacity is of about 1.5 million eggs comprising:

• 2 concrete tanks for breeders (6.5 × 0.8 × 0.8 m)
• 1 concrete tank for breeders (3.5 × 1.5 × 0.8 m)

The water supply for the hatchery is by pipe with a maximum total capacity of 50 1/sec.

The temperature of the water in the hatchery was high (14°C) and therefore now, before its utilization in the incubation system, the water passes through one of the breeder tanks and goes out of the hatchery by one of the discharge canals. This canal is uncovered and about 20 m long. During this passage, the temperature of the water drops by about 2°C (air temperature during this period is about 3–4°C) and can equilibrate with air; it is pumped again to the incubation devices at a temperature of about 12°C.

2.2.1.3 Nursing tanks

(Figure 2 [3])

Near the hatchery, under a roof of 1 200 m², there are 204 fibreglass nursing tanks (Figure 3).

They are rectangular in shape and measure 350 × 60 × 50 cm; they are trapezoidal in sections and are arranged in 6 rows of 17 pairs each. The water level is regulated by two holes on the front of the tank. The water is supplied by iron tube (2 inch) with a ½ inch value placed on the head of the tanks. The maximum water exchange is 1 1/sec for each tank.

2.2.1.4 Concrete nursing basins

(Figures 2 - A-B-C)

There are 98 circular-shaped underground basins, 5 m diameter, 1 m depth, about 20 m³ capacity. They have a central discharge on the bottom with an external level pipe and a lateral safety discharge. The water supply is by a radial 2 inch pierced tube with a water exchange of 1.5–4 1/sec. Twenty double rectangular raceways (21 × 1.5 m) are divided in 3 sections of 7 m each. The water supply is about 2.5–4 1/sec. Finally, there are 6 double raceways 30 m long and 5 m wide for the parent stock. All these basins are in concrete (both walls and bottom) (Figures 4 and 5).

2.2.1.5 Water Supply

The water is continuously pumped from a spring 3 km away with a pump of 250 1/sec capacity (1 working and 2 supply) by means of a 60 cm diameter tube to an elevated tank (≃ 10 m) from which the water is distributed by gravity through tubes to all the basins. A new pipeline is being built and will be ready shortly. The total water supply (2 pumps working) will reach about 500 1/sec. The maximum water supply for each breeding facility is:

The temperature of the water in the spring is 14°C; there is no decrease of temperature in the underground pipeline and the temperature in the basins ranges between an average 13°C during the winter and an average 16°C during the summer (maximum 19°C) according to the air temperature.

The following analyses were made by the GEF operators (at Ath Thawra Laboratory) on 24 May 1982 (14.00 h) by means of a HACH portable equipment.

(1) Inlet water;
(2) Into the tank;
(3) Outlet water

2.2.1.6 Management

In the hatchery, reproduction is carried out with domestic parent stock, but until now with a very low survival rate (5.4% at the fry stage, 1981–82 reproduction). Incubation of eyed eggs from abroad (mainly from Italy - Piscicoltura Leonardi, Priore di Trento) is also carried out. These eggs are incubated for 7–10 days in the Californian troughs until they hatch. During this period they are treated with iodine and malachite green (2.5–4.5 ppm for 30 min). The larvae remain there for 12–14 days and the fry are then transferred into external nursing tanks where they stay until they weigh about 0.5–0.8 g. At this point they are transferred into the concrete nursing basins, both circular and rectangular, at a density of 1 500–2 500/m². With imported eyed eggs the survival rate is higher with ≃ 16.9% at fingerling stage for the 1980–81 reproduction (and improved further with ≃ 50% at fingerling stage 1–2 g), due to the adoption of the cooling system of the water used for incubation (see Section 2.2.1.2). They stay in the nursing basins until they weigh about 5 g at which stage they are either transported to other fish-farms or grown in the Zabadani basins to a marketable size (200–250 g). The food used is Trouvit (Trouw Italia S.p.a., S. Zeno di Mozzecane, Verona, Italy) for the fingerlings at a ratio of 4% daily distributed by hand every 2 hours and locally-made large pellets (4.5 mm in diameter) for the larger fish. The conversion factor is 1.7:1 for the fingerlings and 1.5–2:1 for the others.

Nineteen persons are employed on the farm plus 1 Japanese volunteer.

2.2.1.7 Production

In 1980 the production declared was 27 t of trout of marketable size and 1 million fingerlings of 5 g. In 1981 the production of trout was less (17 t and 5 t for brood stocks, and 1 million declared fingerlings (however, a more realistic figure would be 623 999) of 5 g, of which 450 000 for Sin farm).

A production of 20 t of edible trout (31 t planned) is foreseen for 1982 and 1 million fingerlings.

The potential production of the plant is 1.5–2 million fingerlings.

2.2.1.8 Observations

• In general there is a lack of care in management of the facilities and lack of cleanliness in the troughs, the tanks and the working tables with a consequently high possibility of transmission of pathologies.

• The water is pumped from a distant spring at high cost for the pumping system, the pipeline, the electricity and the supply remain precarious. The quality of the water is probably not very good.

• The pH is relatively high (8.0) (the higher the pH value, the higher the percentage of toxic unionized ammonia, dangerous particularly when the exchange rate is not very high and the metabolites accumulate).

• The free CO₂ is relatively high (22 mg/1). (High levels of CO₂ cause acidosis of the blood and of the urine. This can interfere with the normal kidney activity and cause the formation of calcium phosphate deposits, nefrocalcinosis.)

• The DO is not very high and represents 90% of the saturation.

• The content in dissolved gases, such as N₂, is probably high, and this can cause the gas bubble disease and other problems during incubation, e.g., the formation of a gas-cushion under the eggs that stops the water flowing through them.

  The elevated distribution tank is too small and the water arriving and departing by tube cannot equilibrate with the air to liberate CO₂ and N₂ and increase the O₂ content.

• Eyed eggs from abroad are unnecessarily put into the Californian trough and then transferred to the nursing tanks. They could be released directly into the nursing tanks thus reducing stress.

• In general all the tanks and basins are small; the farm is divided into many small units, and is built and arranged in a bizarre fashion.

• The growth of grass between the basins and the ground is irregular; therefore the internal transport and daily management are difficult and tiring.

• Imported food is stocked in large quantities in a warehouse in open bags and the food becomes stale losing vitamins and nourishing power. The local food is generally more than 3 months old and sometimes even more than 9 months old.

• The basins are often overcrowded, particularly considering the water supply.

• Fish do not show symptoms of any particular disease. There are some fish in the basins which are dark in colour, showing normal liver under necropsy, empty gut, normal kidney; the gills are a little anaemic. No parasites have been found either on the gills or on the skin. No gas bubble disease symptoms have been recorded at present. Several fingerlings showed bacterial and traumatic lesions on the first ray of the dorsal fin, probably connected with overcrowding.

• There is no laboratory for quality control of the water and general health of the fish.

• Trout is not at the moment a fish which is well accepted by the market both because of the price (£S 15¹) and because of the unfamiliar shape. Given this fact, the potential production of Zabadani (1.5–2 million fingerlings) is excessive.

2.2.1.9 Conclusions and recommendations

As it is not possible to modify the structure of the plant or the characteristics of the water supply system, few recommendations can be made:

• to identify the dissolved gases and their quantity in the water of the spring and the basins;

• to build a degasing-equilibrating tank between the elevated distribution tank and the distribution system, with overlayed screens and other degasing systems (water mill, etc.) in which the water can liberate CO₂ and N₂ and increase the O₂ content;

• to put the eyed eggs on pierced aluminium trays directly into the external nursing tanks to avoid one point of transfer and subsequent stress to the fry;

• to utilize good quality food, both for fingerlings and for larger size fish not older than 2–3 months;

• to calculate on a weekly basis the exact quantity of food the fish in each tank need, by sampling and weighing a suitable number of fish;

• to institute a laboratory to check frequently the quality of the water and the health of the fish;

• the basins should not be overcrowded but stocked in accordance with the supply and the quality of the water;

• to instruct personnel in better management with particular reference to prophylactic treatment and cleaning of tanks and basins, etc.

• to pay particular attention to the conditions of breed stock, both for food quality and for water supply.

2.2.2 M'zeirib Fish-Farm

2.2.2.1 General

The farm is located near the Jordanian border, about 100 km to the south of Damascus; the total area is about 8 ha, of which about 6 ha of water. The plant produces carps and tilapia, both fingerlings and marketable size.

2.2.2.2 Facilities

(Figure 6)

The farm is formed of:

• 17 fattening earthen ponds (Figure 6: 1–17) (Figure 7)

• 2 ponds for parent stock (A carp - B tilapia)

• several concrete basins (20 × 4 m and ≃ 6 × 4 m) for spawning and nursing (Figure 8).

There is also a warehouse and a house for the director.

¹ Exchange: US$ 1.00 = Syrian pounds 3.90 (June 1982)

2.2.2.3 Water supply

The water is pumped from a ≃ 30 ha lake, formed by warm springs with an average temperature of about 24°C. The water is pumped to an elevated tank and from this is distributed to the basins by means of underground pipes by gravity. There are 3 pumps of 135 1/sec capacity each, one working and two of supply; the water is collected from the ponds by canals and brought back to the lake. The temperature in the ponds ranges from a minimum of 17°C to a maximum of 29°C.

2.2.2.4 Management

The species reared are common carp (Cyprinus carpio) and tilapia (Sarotherodon aureus, S. nilotica, Tilapia zilii) for both fattening (marketable size respectively 400–600 g for carp and 150–300 g for tilapia) and fingerling production, both for the same farm and for other plants (Shata; Ath Thawra). The reproduction is natural in ponds or in concrete basins; tilapia can survive with this water temperature during the winter.

2.2.2.5 Production

The annual total production is 15–17 t of marketable fish (50% carp and 50% tilapia) and 600 000 carp fingerlings and 40 000 tilapia fingerlings.

The tilapia fingerlings are only for the same plant, the carp fingerlings are also destined for the Room Dam plant.

The food used is locally-made pellets, broken for the smaller fish. The conversion factor is 3.5:1 for fish up to 100 g and 3:1 for larger fish.

2.2.2.6 Observations

In general, the farm has no major problems and the temperature of the water is good both for growth of fish and for reproduction, and for survival of tilapia brood stock during the winter.

Nevertheless it is observed:

• the quality of the water is not controlled, particularly in this closed-cycle situation

• in 1982 a massive infestation of Argulus sp. has been recorded on carp brood stock fished in the ponds

• there is no regular schedule of prophylactic treatment

• there is a general lack of care in management.

2.2.2.7 Conclusions and recommendations

The farm does not present any particular problem and is representative of the general status of the fish-farm in Syria.

The following can be recommended:

• the food should be no older than 2–3 months and should be stored in a place which is both dry and closed

• the quality of the water should be monitored as well as the health of the fish by frequent checking and sampling

• the brood stock should be disinfested before being released into breeding ponds to avoid transmission of parasites

• all farm operations should be recorded so that the population of the ponds and the status of the farm are known.

2.2.3 Room Dam

2.2.3.1 General

The plant is located at about 100 km southeast of Damascus on the hills below a dam near Suwayda, at approximately 1 100 m above sea level; it occupies about 8 ha of which 6 ha of water. It cannot be enlarged. It is only used for fattening carp during the summer.

2.2.3.2 Facilities

The plant is formed mainly by 10 earthen ponds of different sizes and one concrete pond (Figures 9 and 10). There is also a house for the director.

2.2.3.3 Water supply

The water supply comes from the bottom of the lake formed by the dam, and by collecting snow and rainwater off the surrounding mountains. The waters are mainly destined for drinking purposes by the nearest town population and thus the water is not always available for the farm. The water is drawn from the lake by a pipe passing under the dam with a maximum of 50 1/sec. The temperature is low (approximately 14–15°c) and reaches a maximum of 30°c in the ponds during the summer.

2.2.3.4 Management

This farm is concerned with the fattening of carp only during the summer, with fingerlings coming from M'zeirib in the spring. The food used is locally-made large pellets and sometimes maize. (Fingerlings are transported to the plant by road from M'zeirib and the yield is transported in the same way to the market.)

2.2.3.5 Production

The annual production is about 20 t (planned 21) of carp of marketable size, corresponding to a yield of about 3 t/ha.

2.2.3.6 Observations

The plant depends for its water supply on the availability of water from the lake - water which is mainly devoted to drinking purposes; the temperature of the water, moreover, is low, and the growth of fish is possible only in the summer.

2.3 SIN BRANCH

The sin Branch includes the Masab Fish Complex Farm formed by the two farms of Nib Al Sin and Masab Al Sin, which utilize the water of the springs of Lake Sin. Here, many small springs form a number of small lakes and finally one big lake is formed by a dam, on the other side of which the water forms a small river. In the springs the water is clear, in good quantity (8–12 m³ /sec) and spouts out of a deep source at a temperature of about 15–16°C. There are numerous gas bubbles rising from the bottom of the water. They are odourless and the pH of the water is 6.5–7. The vegetation is poor and unvaried and so are the animals (few tadpoles, crustaceans and Gambusia sp.). An experiment with trout transported from the Sin farm was negative and the fish died within one hour. The water for the Nib Al Sin trout farm is pumped from the big lake (depth 4–10 m); on the other side, water is drawn by gravity from the little river for the polyculture activities of Masab Al Sin, located 4 km away.

2.3.1 Nib Al Sin Fish-Farm

2.3.1.1 General

The farm is located 50 km south of Latakia near Baniyas; it has a total surface of 3 ha of which 1.6 of water, and trout is reared to a marketable size.

2.3.1.2 Facilities (Figure 10)

The plant is formed by 112 concrete basins of 36 × 4 × 1.30 m with a capacity of 144 m³ of water each (Figure 12). The water has an inlet by a pipe of 3 inch and an outlet in a corner on the opposite side ≃ 40 cm wide (Figure 13). The basins are coupled and underground. Only 110 of them are working. Underground concrete canals collect the discharged waters.

2.3.1.3 Water supply

About 1 m³ /sec of water is pumped from the Sin Lake at a depth of 4–5 m to an elevated tank from which it is distributed by iron pipes by gravity to all basins.

The maximum flow rate for each basin is 8–9 1/sec. The temperature of the inlet water ranges from 15° to 20°C with a reported medium content of oxygen of 9 mg/1 (7.5–10 mg/1). At the outlet the oxygen is reported to be on average 6 mg/1 (3.5–7 mg/1). In the basins the temperature increases during the summer to a maximum of 23.5°C and minimum of 18°C in August and decreases during the winter to a maximum of 17°C and a minimum of 14.5°C in January.

2.3.1.4 Management

The fingerlings come from the Zabadani farm some 400 km away, a journey of 6–10 h; they have an average weight of 7–15 g (20–30 g depending on the year). They are released into the basins at a density of about 15 000 to each basin. When they reach an average weight of 40–50 g (70–80 g), they are selected and divided. The final density is of about 2 500–3 000 fish (weighing 250 g each) for each basin. The water supply for each basin is always 8–9 1/sec.

For 1980/81 data are as follows:

• early 1980 eyed eggs imported from Italy to Zabadani

• June 1980 - fingerlings are transported to Sin farm (average weight 20–30 g)

• from August to December 1980 - selection (average weight 70–80 g)

• from February to November 1981 - yield (medium weight ≃ 200 g)

The selections are made by means of a 4 inch pump and a set of 4 different bar grades and by netting the fish manually.

The food is distributed manually three times each day to fingerlings (imported food - Trouvit, Trouw Italia) and twice each day to larger fish (locally-made big pellets). The expected conversion factor is 1.4:1; the factor obtained with Trouvit is 1.7:1 and 2:1 with the local product.

The cleaning of the bottom of the basins (detritus and vegetal matter) is done manually by brooms and rubber rakes; a staff of ten is employed on the farm plus one Japanese volunteer.

2.3.1.5 Production

The total production of 1980–81, collected over a period of 10 months, was 67 t of trout weighing 200–250 g. The yield of each single basin is about 650–750 kg of fish (2 300 fish of 250 g or 3 700 fish of 200 g).

The theoretical production of the plant at present can reach 75–80 t. The planned production for 1982 is 150 t.

2.3.1.6 Observations

In spite of the quantity of pumped water (1 m³ /sec), the production is low. This may be attributed to the general structure of the farm, with many small basins with too little water flow in each. Thus, with the poor quality of the water (high temperature, high content of dissolved gases - CO₂ and N₂, low values of dissolved oxygen), and the poor quality of the food, the conditions are not very good for the fish which show general discomfort.

In particular the following can be observed:

• There is no long-term information on the quality of the water and in particular on the nature of the gas which forms the bubbles in the spring and which caused a massive mortality of fish in September 1981 through “gas bubble disease” with its typical symptomology.

• The water supply for each basin (8–9 1/sec) is too low. The current flow in the basins is about 0.2 cm/sec, one-tenth of the velocity of the water in trout fish-farm in general in Italy. This causes a deposit of suspended solids, like the faeces of fishes, and so encourages the growth of vegetal matter which consumes oxygen during the night and increases the quantity of solids.

• Some of the collecting discharge canals are not the correct size or depth, and therefore it is not always possible to dry all the basins completely.

• The cleaning operations with brooms and rubber rakes can damage the gills of the fishes and cause trauma and stress.

• Specific pathologies are not present but a condition of discomfort can be identified by the presence of dark coloured fish - some fish with exophthalmus, dirty and kneaded gills. Under necropsy the fish are normal with slightly light-coloured liver.

  The gills are dirty and ematoma is present in the secondary lamellae. No parasites have been found either on the gills or on the skin.

• There is no accurate schedule for farm operations and the time of the release of the fingerlings from Zabadani; their size and the general management of the plant seem to depend on circumstances.

2.3.1.7 Conclusions and recommendations

The dimension of the basins, the quantity of the water supply and the other characteristics of the farm cannot be changed, and every structural modification requires substantial investment. (One possibility was to unify 4 basins into one, to obtain 10 new basins about 150 m long plus 13 old basins; i.e., to have 26 basins 150 × 4 m with 40 1/sec each).

Without any change in the present facilities, it is recommended:

• that the nature of the gas of the spring be determined. However, whatever the gas is, the water should be stirred both to eliminate this gas and to increase the O₂ content. This may be done in the same elevated tank or at the inlet into the basins.

• that the quality of the water and the state of health of the fish be checked frequently so that the situation of the basins may be known at any given moment.

• that the cleaning system be changed utilizing a pump that sucks up detritus instead of raising it in the water with brooms and rubber rakes.

• that the food be no older than 2–3 months; after this it loses vitamins and the fish suffer.

• all operations such as the distribution of fingerlings and the food supply should be well planned and well organized for good management.

2.3.2 Masab Al Sin Fish-Farm

2.3.2.1 General

The farm is located on the coast near Baniyas, 50 km south of Latakia and 4 km from Nib Al Sin with which it constitutes the Masab fish-farm complex. It uses the water of a river that comes from the same springs of Sin Lake; it has a total surface of about 80 ha of which about 60 of water and it produces mainly carps and tilapia both in polyculture and in monoculture.

2.3.2.2 Facilities

(Figure 14)

The plant is mainly formed by:

The ponds are made of earth with a maximum water depth of 1.8 m and a minimum depth of 1.2 m (Figure 15). They are rectangular in shape; the inlet is by a tube on a corner and the outlet by a concrete monk on the opposite corner. A concrete platform (harvesting sump) is located near the monk.

2.3.2.3 Water supply

The water comes by gravity from a river originating in the same springs of Sin Lake. During this passage, the water can equilibrate with air. The total water supply is of 250–300 1/sec at maximum, with a pH of 7.25.

The temperature of the water in the ponds without exchange can reach high values, considering also the temperature of the air reported below (the values are averages for the years 1955–1973):

2.3.2.4 Management

The species reared are:

• common carp (Mirror carp) (Cyrinus carpio)
• tilapia (Sarotherodon aureus) (best)
  
  (Sarotherodon galileus) (good)
  (Tilapia zillii) (now abandoned)
  (Sarotherodon niloticus) (experimental)
• grass carp (Ctenopharyngodon idella) (to control vegetation)

  occasionally the following are also present:

• mullet (Mugil cephalus)
  
  (Liza saliens)

  catfish (Clarias lazera)
  eel (Anguilla anguilla)

Fattening is carried out with fish reproduced on the same farm. Reproduction for carp is natural with “hapa” in the nursing ponds (Figure 16). In 1981 the nursing ponds were treated with lime (400–600 kg/ha) and fertilized with chicken manure (3 t/ha).

Reproduction of grass carp (Ctenopharyngodon idella) was tried by hormone stimulation, and obtained eggs both by natural spawning and by stripping. The fertilized eggs hatched but the larvae died probably because of a massive presence of Cyclops which had grown in the tanks used as a warming reservoir to increase the temperature.

The schedule for common carp is as follows:

During 1981 polyculture of carp and tilapia were carried out as well as heterosexual monoculture of tilapia.

An example of polyculture is reported in the following table and was carried out in a pond of 3.23 ha.

Species	Start (Spring)		(August) W (g)	End (Autumn)
	No. /ha	o (g)		Mortality (5%) (No.)	No. /ha	i (g)	Wtot/ha (kg)	Wtot (t)
Tilapia	7 500	50	-	375	7 125	330	2 351	7.6
Carp	5 000	25	(698 ± 170)	250	4 750	830	3 942	12.7
Grass carp	25	3 000	-	-	-	-	-	-
Total	12 525	-	-	-	-	-	6 293	20.3

In monoculture an experiment was made with Sarotherodon aureus in a 0.44 ha pond, fertilized only once with cow dung (3.4 t/ha). With the water supply necessary only to maintain the level and with artificial food (locally-made pellets, 14 t) a yield of 4 345 t of marketable size fish was obtained (corresponding to about 10 t/ha in 194 days) plus 200 000 fingerlings collected continuously during the period.

The conversion factor was of about 3:1. The average weight (g) of fish is reported in the table below:

¹ Average between males and females assuming a sex ratio of 1:1

During 1981, the fertilization plan was:

For 1982 the following is planned:

2.3.2.5 Production

The production (t) of 1980 and 1981 and planned for 1982 is shown in the following table:

On the basis of availability of fingerlings, the anticipated total production for 1982 is 280 t.

A production plan for Masab Al Sin by the UN volunteer¹ estimates a possible total carp production of 303 t of 900 g carp/year with 50 ha of fattening ponds stocked with 7 500 fingerlings of 30 g each and a 10% natural mortality.

¹ Second Production Plan for Masab Fish-Farm Complex, Sin Fish-Farm Unit, S.A.R. by Mohammad Gulam Hussain, UN volunteer

2.3.2.6 Observations

The farm is probably one of the most productive and active in the country but suffers from technical as well as managerial handicaps, for example:

• the small size of the discharge pipe (now in substitution)

• the small size of the harvesting sump

• the inlet water is far away from the harvesting sump and has no screen to impede the entrance of fish

• one pond cannot be used because of the permeability of the bottom

• it is not possible to empty all the ponds completely, both because the discharge canals are not sufficiently low and because they also collect rain water from the fields and are therefore sometimes full and unable to receive water from the ponds

• there is a large quantity of grass on the embankment and sometimes in the ponds

• there is a conspicuous predation on fry by water snakes and frogs

• there is no small-size food and pellets have to be broken

• the scheduled liming and fertilizing operations are sometimes not carried out because of the lack of quicklime and fertilizers

• the quality of the manure depends on the availability of the moment and is not planned

• the food (locally-made big pellets) is old (6 months and more) and loses vitamins and nutritional power

• there is no support laboratory for water quality control and control of biological and sanitary problems

• the hatched larvae of grass carp died probably because of a massive infestation of Cyclops. During 1981, the fingerlings of tilapia died due to an infestation of Trichodina sp. in March and Chilodonella sp. in December, both connected with low temperature, bad food, etc. A small laboratory which could carry out timely diagnoses would be helpful.

2.3.2.7 Conclusions and recommendations

The farm has good prospects and could have a very high production both because of the characteristics and productivity of the place and the enthusiasm of the staff.

Nevertheless, the following should be borne in mind:

• the drying, liming and fertilizing operations must always be done with the correct quantity and quality of products. The old quicklime (CaO) turns into calcium carbonate (CaCo₃) which has no value as a pond sanitation chemical;

• the food must be no older than 2–3 months to avoid a lack of vitamins;

• the inlet should be screened to avoid entrance of other fish into the ponds;

• the artificial reproduction permits a greater control of the number of fry and allows chemical treatment. In this way a small hatchery could be equipped with filtered heated water coming from a pond with some hatching jars and other facilities;

• the grass can be controlled in the ponds by the grass carp (100–200 fish/ha) and on the embankment with chemical treatment (Dalapon - 2.2 Dichloropropionic acid - aqueous solution of 0.7%; 6–11.5 kg/ha as foliage treatment);

• the snakes can be caught by traps (cylinder made of wire screen - mesh 0.5 mm) Ø 25 cm, 70 cm long fitted with conical entrance at each end) set near the feeding places and near the shores. Frogs need a barrier ≃ 50 cm high around the pond, justified only if they are a big problem;

• polyculture can utilize the productivity of the pond better than monoculture. However, a study should be made on the best composition in relation to the characteristics of the soil and the productivity of the ponds;

• it is recommended, moreover, that routine checks and recordings be made on the main characteristics of the water (T°C, Do, pH, NO₂-, NH₃) and the characteristics of the pond (number of fish, species, mortality, size, growth, etc.) so that the situation may be known at any given moment and management may be adapted to the evolution of each pond.

2.4 AL GHAB BRANCH

The Al Ghab Branch includes four fish-farms all located in the Al Ghab Valley. This valley was a swamp until 25 years ago. Reclaimed by foreign companies that build drainage canals, it is now one of the most fertile regions of Syria, very rich in water coming from many warm springs.

2.4.1 Ain Al Taka Fish-Farm

2.4.1.1 General

This plant is the oldest in Al Ghab Valley after Kalaat Al Moudiq, and is located to the east in the southern part of Al Ghab Valley at about 120 km from Latakia. Near warm water springs, it has a total surface of 44 ha of which 43 ha of water. It produces carps and tilapia for the market, and fingerlings for the same farm and for other plants (Shata).

2.4.1.2 Facilities

The farm is formed mainly by 8 fattening ponds (4–8 ha each) with a total surface of 41.5 ha and 4 nursing ponds (total surface 2 ha) (Figure 17). There is also a warehouse for the food and the director's house. All the ponds are earthen with a maximum depth of 2 m and a minimum of 1 m. There are also small concrete basins to stock the fish before market or transport.

2.4.1.3 Water supply

The water supply is guaranteed by a canal of 300 1/sec maximum capacity coming from a lake formed by the Ain Al Taka springs. The water in these springs is warm with a temperature of about 20°C; the temperature of the water at the inlet of the farm ranges from a maximum of 25°C during the summer to a minimum of 18°C during the winter. A canal distributes the water to all the ponds but some of these have springs.

2.4.1.4 Management

This farm grows common carp (Cyprinus carpio) and tilapia (Sarotherodon aureus and S. galileus) in polyculture; a few grass carp (Ctenopharyngodon idella); and occasionally there are catfish (Clarias lazera) and silurus (Silurus glanis) which enter from the unprotected canal.

The ponds are filled with water and the level is maintained adding water to compensate the losses for evaporation and drainage. Some water is added to increase the oxygen availability in particular periods during the summer. The fertilization programme for 1982 foresees:

• cow dung 5 m³/ha; and once the pond is filled

• ammonium nitrate (25%N) 600 kg/ha (75 kg/ha/month for 7 months)

• triple superphosphate (48% P₂O₅) 200 kg/ha (100 kg/ha twice a year in March and June)

The fingerlings of carp and tilapia are produced in the same plant; both are transported from M'zeirib. Fingerlings of tilapia which in some of these ponds with springs on the bottom, can survive during the winter, are transported from Ain Al Taka to other fish-farms.

For carp fingerlings the schedule is:

For the fattening ponds the following is foreseen:

2.4.1.5 Production

In 1981 the nominal production was of 120 t of tilapia and 85 t of carp.

For 1982 the planned production is:

2.4.1.6 Observations

The plant has no particular problems; however, the following observations may be made:

• a lack of long-term analyses of water quality
• grass is growing on the embankment and some ponds are very rich in phytoplankton
• some ponds are very suitable for the survival of tilapia during the winter having warm springs on the bottom. The same springs prevent the ponds from being drained completely and fishing is therefore carried out by nets with fish remaining in the mud. In this situation, and with the following constraints: transferring to the stocking ponds without water (15–20 min); stocking period in a concrete basin to reach the sufficient number for transport; a new fishing and transporting system with a tank on truck (150 kg fish/m³) to the other farms; transfer in new water without acclimatization; the losses are very high (mortality rate ≃ 70%).

2.4.1.7 Conclusions and recommendations

The conclusions and recommendations for the fish-farms of Ain Al Taka, Shata and Rouje are found at the end of the description of Rouje.

2.4.2 Shata Fish-Farm

2.4.2.1 General

The plant is located to the west of the southern part of the Ghab valley at about 10 kg from Ain Al Taka. The farm has a total surface of 65 ha of which about 61 of water, and grows carps and tilapia both in polyculture and in monoculture in earthen ponds.

2.4.2.2 Facilities

(Figure 18)

There are 27 fattening ponds (1–27) of 2 ha each; 12 nursing ponds (A 1–12) of 0.5 ha each and 1 rearing pond (B) of 0.6 ha. There are also a warehouse for the food, a house for the director, and 27 unutilized spawning ponds.

2.4.2.3 Water supply

The water is supplied by gravity from a canal (a new one replaces the old one) with a maximum flow of about 200 1/sec coming from a lake formed by springs with an average temperature of 16°C. In the ponds the temperature ranges from a minimum of 9°C during the winter to a maximum of 28°C during the summer.

2.4.2.4 Management

The farm grows common carp (Cyprinuscarpio) and tilapia (Sarotherodon aureus and S. galileus) both in polyculture and in monoculture. The fingerlings are reproduced in the same plant, transported from other farms (Ain Al Taka, M'zeirib).

The feed is locally-made pellets distributed by hand in each pond. No information is available on the fertilization schedule. For 1982, the planned fattening programme is:

Production

In 1981 the production was:

The estimated production of 1982 is:

The planned production for 1982 is:

The low tilapia production in 1981 is due to the high mortality (over 70%) of the fingerlings transported from Ain Al Taka.

2.4.2.5 Observations

• The farm shows a lack of care in general

• grass is growing both on the embankment and in low-level ponds; in particular ponds Nos. 26 and 27 in which the depth of the water is less than 50 cm

• old food is stored in large quantities in an open warehouse where the bags are open

• quicklime is abandoned for a long time in the open air and transforms into calcium carbonate

• longterm characteristics of the water and the general health of the fish are not known

• the slope of some canals is not correct and it is not possible to fill some of the ponds completely, e.g., Nos. 26 and 27, with consequent growth of grass

• when the Asi river, which receives the waters discharged by the farm, floods, it is not possible to dry the ponds

• sometimes the very abundant phytoplankton produces a lack of oxygen in the early morning

• during the winter the tilapia died, the temperature dropping to 8°–9°C

• the mortality of the fingerlings of tilapia transported from Ain Al Taka is very high, both because of the harvesting system, and because of the transport and maybe also because of the different quality of the water.

2.4.2.6 Conclusions and recommendations

The conclusions and recommendations for the fish-farms of Ain Al Taka, Shata and Rouje are to be found at the end of the description of Rouje.

2.4.3 Rouje Fish-Farm

2.4.3.1 General

The plant is located to the north of the Ghab valley near Idlib. The total surface is about 20 ha of which about 60 ha of water. The farm grows carps and tilapia, both in polyculture and in monoculture.

2.4.3.2 Facilities

The plant is mainly formed by 12 fattening ponds of ≃ 5 ha each (Figure 19) 19 rearing ponds of 0.5 ha each, 19 spawning and nursing ponds (Figure 20) and 4 concrete stocking basins (Figure 21). There is a warehouse and a house for the director.

2.4.3.3 Water supply

The water arrives by gravity by means of a canal from the connection between two small spring lakes (Figure 22) with a maximum of 250 1/sec. When the flow by gravity is not enough, because of high withdrawal for irrigation, two pumps can increase the water flow.

For 1983 a well is planned.

The temperature of the water of the spring is about 14°C and the temperature in the ponds ranges from a minimum of 12°–13°C during the winter to a maximum of 31°C during the summer. In May the temperature in the ponds was 22°C on an average.

2.4.3.4 Management

The farm grows carps and tilapia in polyculture and for 1982 also in monoculture. The schedule for 1982 is as follows: 167 000 tilapia fingerlings in monoculture in 3 ponds (33 400/ha) to give a total yield of 30 t (6 t/ha) and 100 000 fingerlings in polyculture with 78 000 carps in 3 ponds (11 800 fingerlings/ha, in total, respectively 6 600/ha for tilapia and 5 200 for carp) giving a total yield of 65 t (4.3 t/ha). Monoculture of carp foresees 260 000 fingerlings producing 125 t.

Feed is locally-made large pellets broken for the small fish, given normally in three or four places on each pond on the bottom near the shore. The food rate is about 4% of the weight of the fish.

Fertilization with cow dung is carried out only in the nursing ponds. The ponds are filled with water and water is added only to compensate evaporation and drainage.

2.4.3.5 Production

The 1981 production and that planned for 1982 are shown in the following table:

All the tilapia fingerlings are for the same farm.

The carp fingerlings K₁ (20 g) are for the same farm; the other (≃ 80 g) are for the floating cages of the Ath Thawra plant.

2.4.3.6 Observations

• The grass invades the embankments and part of the ponds (Figure 23);

• At the moment, all the daily ration of food is put in only one place in the pond, on the bottom near the shore (Figure 24);

• The water is not always available depending on the withdrawal for irrigation;

• No prophylactic treatment is programmed (during 1979-80 a high mortality (about 200 000 fish) occured because of a massive infestation of Ichthyophthirius.)

• The quicklime is exposed to the sun and the air for a long time, transforming into calcium carbonate;

• There is no longterm information on the water characteristics and on the general health of the fish;

• Sometimes there is a lack of oxygen in the early morning which is a cause of the abundant phytoplankton.

2.4.3.7 Conclusions and recommendations

The plants of Ain Al Taka, Shata and Rouje are similar, and therefore the conclusions and the recommendations can be unified.

The characteristics of the plants and of the waters are suitable for warm water fish culture, and the specific production is good. Nevertheless it can be improved with better management with a programmed schedule of operations relative to:

• the production of correct number of fingerlings of suitable size

• the adoption of prophylactic treatment against parasites

• the disinfection of the ponds with quicklime (not CaCO₃)

• the fertilization of the ponds with suitable quantity of fertilizer: the best results can be obtained with continued regular applications. Only one fertilization lowers heavily the DO and the food production is limited in time. Regular fertilization, with chemical fertilizer as well as with manure, allows a better control of pond productivity, avoids peaks of O₂ consumption and provides a continuous production of food for the fish

• the introduction of the fingerlings at the right density

• the feeding of fish with suitable fresh food put in a proper place (near the harvesting sump or by means of “demand feeders”)

• the weekly adjustment of the food ration to the size of the fish

• the routine check of the characteristics of the water

• the routine check of the health and growth of the fish

• in particular a study of the better composition of the species in polyculture is necessary. The ratio must be selected according to the productivity of the ponds, in order to give the best utilization of the natural food and the best fish production

• moreover, in all the plants it is necessary to control the grass, both on the embankment (chemical treatment with Dalapon) and in the ponds (grass carp, 100–200 fish/ha)

• it is important to avoid the presence of undesirable species in the ponds, protecting the inlet canals with screens

• the deleterious transfers of fingerlings from plant to plant must be avoided; and fingerlings should be reproduced in each farm

• to ensure the survival of the parent stock during the winter, floating cages can be put directly into the spring lakes, where the temperature remains above 16°–20°C.

2.4.4 Kalaat Al Moudiq Experimental Fish Culture Station

2.4.4.1 General

The station is located to the east in the southern part of the Ghab valley near the Ain Al Taka farm. Built in 1959 with FAO support, it has operated as a training centre since 1964. It was closed in 1979 and some renovations are now being carried out to enable the plant to produce fingerlings for the other farms.

2.4.4.2 Facilities

The station comprises 19 earthen ponds covering a total surface of ≃ 3 ha. The basins are not in use because of renovations (it was not possible to empty some ponds completely and others have broken embankment or monks, etc.). There is a hatchery with 56 Zugg jars of about 25°C capacity each, 8 circular fibreglass tanks (diameter ≃ 15 cm, 40 cm depth) with central elevated drainage outlet for larvae rearing; 8 rectangular tanks (≃ 2 × 1 × 1 m) and outside the hatchery there are 2 concrete basins trapezoidal and in sections ≃ 12 × 6 × 3 m. Only the hatchery was operating (Figure 25).

2.4.4.3 Water supply

The water (maximum 50 l/sec) is derived from the nearby spring lake in which the temperature is 24°–25°C (20°C at minimum). For the hatchery the water is prefiltered by a gravel filter. During reproduction in 1982 the water temperature was about 22°–23°C.

2.4.4.4 Management

Artificial reproduction of common carp (Cyprinus carpio) and grass carp (Ctenopharyngodon idella) is supervised by two Japanese volunteers, the brood stock coming from Shata. The larvae obtained are transferred to other plants.

2.4.4.5 Production

For 1982 planned production is:

As at 2 June 1982 production was:

6 200 000 larvae of common carp

35 000 larvae of grass carp

Grass carp reproduction is being carried out.

2.4.4.6 Observations

• The general impression of the centre is lack of care and a general situation of abandon

• some ponds and monks are broken but renovation and repair seem to be planned

• the hatchery is sufficiently equipped and produces a good number of larvae but they cannot be grown because of lack of ponds.

2.4.4.7 Conclusions and recommendations

Even if only as a training centre for reproduction and early growth of carp and tilapia, the Kalaat Al Moudiq station can be useful both for fingerling production and training activity; and it is desirable that operations begin as soon as possible.

2.5 ATH THAWRA BRANCH

The Ath Thawra branch operates on Lake Assad, formed by the dam on the River Furat (Euphrates). Here the branch has a station with a staff of three who have been trained in the Federal Republic of Germnay in limnology and fisheries during a 3-year project carried out with a German company (GTZ - Gesellschaft fur Technische Zusammenarbeit) which also had activities on the lake.

The activities of the branch on the lake are mainly on:

2.5.1 Fishery

The lake fishery is carried out by cooperatives of fishermen controlled by the branch which imposes a tax on the fish caught.

The station has a laboratory which carries out routine water analyses in 9 stations on the lake and checks the fish to find out the feeding regime and reproductive cycles. Range-values on an average of the main parameters registered are as follows:

The species present in the lake are listed below:

Acanthobrama marmid
Alburnus mossulensis
Aspius vorax
Barbus esocinus
Barbus grypus
Barbus kersin
Barbus luteus
Barbus sharpeyi
Barbus subquinconiatus
Chondrostoma regius
Cyprinion macrostomus
Leuciscus lepidus
Varicorhinus trutta
Mastacembelus mastacembelus
Liza abu
Silurus glanis
Silurus triostegus
Esox lucius (released in 1977, 100 000 fingerlings of 5 g each)
Cyprinus carpio (in floating cages)
Salmo gairdneri (in floating cages)

2.5.2 Aquaculture

2.5.2.1 Facilities

Aquaculture is carried out by floating cages located in a protected bay (Figure 26). The cages came from a project operated by the Federal Republic of Germany and the first four date from 1977. In 1978, 2 more were installed, 50 in 1980 and later a further 50. At present there are 106 cages.

They consist of a metal tubular frame (4.5 × 3 m) with floaters on one side connected to a floating plank on the other (Figure 27). The net is soft and each cage has about 36 m³ of usable volume (Figure 28).

2.5.2.2 Management

In the cages mainly common carp (C. carpio) is grown during the summer (according to the temperature the growing period is from April to November). During the winter an attempt was made to grow trout. Results have been good (from 40 g to 300 g in 5 months) but there is no market for trout in the area. The programme foresees the introduction of 2 000 fingerlings of carp (40–(60)–140 g) in each cage, and they should attain 1 kg at the end of the growing season. Feed is locally-made large pellets supplied by “demand feeders”.

2.5.2.3 Production

In 1981 production was 85 t of carp. The theoretical production (50 kg/m³/year for all cages) is of 200 t/year. The expected production for 1982, considering fingerling availability, is of 125 t.

2.5.2.4 Observations

The correct weight of fingerlings to obtain the marketable size of 1 kg at the end of the growing season is 60–100 g. This size often is not available as the M'zeirib farm keeps this size of fingerling for internal stocking and sends small fingerlings (15–30 g) which in these conditions (the cages, the short period and mainly the quality of the only food available) cannot reach marketable size.¹

Until now there is no programmed prophylactic treatment of fish against parasites before they are introduced into the cages.

The station laboratory works only in routine analysis and lacks an ichthyopathological section. (Some carps present symptomatology of fish pox associated with Trichodina sp. and ematoma on the gill lamellae.)

¹ It is noted that a plant for the production of 60–100 g fingerlings, to supply only the floating cages is being planned

2.5.2.5 Conclusions and recommendations

The plant is generally in good condition and the production (50 kg/m³/year) is good.

• prophylactic treatment against parasites before release into the cages, is recommended

• the health of fish should be checked frequently for an eventual timely intervention

• the food should be no older than 2 or 3 months as thereafter it lacks vitamins

• when fish pox is present, the fish swell; this condition allows for easy identification of the disease

• when a massive parasitic infestation appears the fish can be treated by chemical bath

• it is recommended that the fingerlings released into the cage be the correct size (the problem of availability will be solved by the new farm)

• to avoid food loss in the early growth period and to facilitate feeding of small fish, a plate or plastic sheet can be positioned underneath the demand feeder or some dough can be smeared on a stiff net attached to the demand feeder rod.

2.6 NEW PLANTS

The feasibility of trout farming is questioned on economic grounds. All new farms for each branch are justified by particular factors other than economic considerations.

2.6.1 Damascus Branch

The Zabadani trout fish-farm in the Damascus branch has to overcome two “bottlenecks”.

1. The theoretical fingerling production is of 1.5–2 million fish. The actual total capacity of seedlings of existing trout farms is limited to 800 000–900 000 fingerlings.

2. Management costs are high.

These two problems can be solved by building a new fish-farm utilizing, by gravity, the water discharged by the existing farm. This new plant can absorb part of the fingerlings produced and lower the production cost per kilogramme, increasing the production of marketable size fish, with the same fixed management cost (electricity, personnel). With the new pipe and a total water supply of ≃ 500 1/sec the new farm could produce 50–60 t. Care must be taken in planning the new farm so that only the good water of the old farm is utilized (with the possibility of avoiding water polluted by chemical treatment and by cleaning operations).

2.6.2 Homs Branch

In this branch a trout fish-farm near Rable is planned. The plant is justified in that:

• there are no fish-farms in this region in spite of the good local market and the nearby Lebanese market

• the farm can absorb part of the Zabadani fingerling production.

The location is in a small valley by the Lebanese border with a small river flowing down from the Lebanese mountains. The available surface is about 2 ha and the water supply from the river can reach 4 m³/sec. An analysis of this water made once by the Ath Thawra laboratory in June 1980 is as follows:

The site appears suitable but attention should be paid to the following:

• to keep longterm records on the quality and quantity of the water

• to verify the possibility of diverting the water before it reaches the Lebanese fish-farm (in Lebanon, near the border, there is a small private trout farm, 20 t/year production) to avoid the risk of transmission of pathologies

• to verify the flood pattern of the river to be able to control it.

2.6.3 Sin Branch

The “bottleneck” of the Sin Branch is the high cost of management of the Nib Al Sin fish-farm. In order to lower this cost, the same staff can be employed on another farm near the Nib Al Sin. The proposed sites for a farm for carp and tilapia are two:

Dugal: this is the first choice. Near the sea, it can use water from the river formed by the Sin springs. The handicap is the nature of the soil which seems sandy and permeable.

The Dugal project foresees a total surface of 120 ha, 80 ha of fattening ponds, 6 ha of nursing ponds, 2 ha of brood stock, a water supply of 500 1/sec by canal from the Sin river; the expected production is 400 t of carp and tilapia.

The second choice:

a farm utilizing water discharged by gravity by the Nib Al Sin fish-farm (1 m³/sec). The available surface is not exactly known but it seems to extend as far as the sea (≃ 2 km away). The remedies for the unsuitable factors in the use of this water (low DO level, high metabolites level, low temperature, transferring pathologies) must be studied.¹

2.6.4 Al Ghab Branch

The Al Ghab valley is a suitable place for the fish-farm of carp and tilapia, particularly for the warm spring water which allows good growth and allows tilapia to survive during the winter. A new plant is planned at Ha Huasch, in the Ain Al Taka region. The ground is now a swamp with springs at 20°C. The available surface is about 100 ha of which 80 ha is utilizable. It seems that all the water flow could be by gravity.

2.6.5 Ath Thawra Branch

At present the fingerlings for the net cages are supplied from M'zeirib and Rouje fish-farms. In order to be able to dispose, at the right moment, of the right number of fingerlings of the right size (100–140 g) a specific fish-farm is being planned near Lake Assad (probably at Maskame). This plant, not far from Ath Thawra, will utilize the same water from the lake derived from an irrigation canal (36 m³ /sec) and will have a surface of 150 ha, with 6 fattening ponds, 50 nursing ponds, 8 broodstock ponds, 2 parent stock ponds, 10 spawning ponds and one for stocking 50 t of fish ready for sale.

The planned production is of 1 million fingerlings, 100 g each, and 150 t of carp and tilapia.

¹ The suitable area near Dugal, with apparently good water and suitable area underneath the falls of the Sin Lake, is not available; during the summer all the water is for irrigation. No alternative place for a trout farm can be found further downstream in the Sin river valley, above the Dugal site. This still has to be investigated. Another location for trout must also be examined : Sourit, not far from Sin, with 3–500 1/sec of water, would appear to be available.

2.7 FEEDING

The food for trout fingerlings is imported from Italy (Trouvit, Trouw Italia) but for larger size trout, carp and tilapia a locally-made pellet is used.

This food is made in a factory which produces mainly food for other animals (cows and chickens) and which has to interrupt this production to convert to fish food production.

The factory follows a given formulation which for 1982 is:

A. food for nursing ponds and floating cages

B. food for fattening ponds

In the formulation, the GEF considers both the nutritional requirements of fish and the availability and the cost of the products on the Syrian market.

In relation to the high cost of the change in production of the factory, food is produced only 2–3 times every year and namely in June, August and October with a unitary production of 1 500 t. The feed is pellets made in two different sizes (2.5 and 4.5 mm in diameter) and packed in 50 kg synthetic bags. It is broken for the smaller fish.

In all the farms, the food is consigned in quantities large enough to last until the next delivery.

2.7.1 Observations

• the food is generally not delivered to the farms quickly and when fed to the fish it is old and has lost most of its vitamins. In particular, this is true for the spring and early summer when the fingerlings start to feed again. At this time, in fact, the food is at least 7 months old. This is partially compensated in the ponds where the fish can find natural food but it can be a problem in the floating cages where the only food available is artificial.

• the system of breaking big pellets to obtain suitably sized food for the young fish, is not satisfactory; a lot of dust is produced and a lot of food is lost. Moreover, each particle is not well balanced with all components.

2.7.2. Conclusions and recommendations

• the present annual requirements of food is about 5 000 t

Considering the high costs of the interruption of the normal production of the food factory and the previous observations, two small factories could be used, one in the Damascus Branch, mainly producing trout food (for Nib Al Sin and Zabadani) and another in the Al Ghab Branch mainly producing carp food (for Ain Al Taka, Shata, Rouje, Kalaat Al Moudiq and Ath Thawra).

Each of these could produce 16–20 t/day of food according to the demand, adapted in formulation and in size.

• the food must not be stored in open and humid warehouses and must be no older than 2–3 months

• at least two formulations with different protein levels have to be available to adapt the final protein content to the size and to the density of fish.