As already mentioned the W. Yabis Fish Farm was established in 1964. It has eight spawning ponds (100 sq m each), two nursery ponds (1,000 sq m each) and three fattening ponds (4,000 sq m each). Due to the very high seepage the ponds, except for one nursery and two spawning ponds, do not hold enough water. In view of the urgent need for ponds to conduct essential experiments, the possibility of improving these ponds was considered. From the end of December 1965 to the beginning of January 1966 studies were made of the seepage rate in the ponds and the results are summarized in Table IV.
Table IV
Seepage Measurements in W. Yabis Ponds
| No. of pond | Beginning of test | End of test | |||||
| Date | Hours | Depth of water cm | Date | Hours | Loss water cm | Seepage cm/hr | |
| 1 | 29.12.1965 | 09.00 | 90 | 30.12.1965 | 04.00 | 90 | 90/19.00 |
| 2 | 29.12.1965 | 11.00 | 100 | 30.12.1965 | 08.30 | 85 | 85/20.30 |
| 1 | 30.12.1965 | 08.30 | 90 | 31.12.1965 | 08.30 | 90 | 90/24.00 |
| 2 | 30.12.1965 | 10.30 | 100 | 31.12.1965 | 10.30 | 85 | 85/24.00 |
| 1 | 31.12.1965 | 10.00 | 90 | 1. 1.1966 | 09.00 | 85 | 85/23.00 |
| 2 | 31.12.1965 | 12.00 | 100 | 1. 1.1966 | 10.00 | 83 | 83/22.00 |
| 1 | 1. 1.1966 | 11.00 | 90 | 2. 1.1966 | 09.00 | 82 | 82/22.00 |
| 2 | 1. 1.1966 | 13.30 | 100 | 2. 1.1966 | 10.30 | 82 | 82/21.00 |
| 1 | 2. 1.1966 | 10.30 | 90 | 3. 1.1966 | 10.30 | 80 | 80/24.00 |
| 2 | 2. 1.1966 | 13.00 | 100 | 3. 1.1966 | 13.00 | 80 | 80/24.00 |
The average seepage rate works out to 5 to 6 cu m per hour. In the opinion of the expert this is too high a rate of seepage to be rectified by any known economical means. However, at the suggestion of the authorities concerned, it was decided to undertake experiments to determine the possibilities of reducing or stopping the seepage.
In one experiment one of the spawning ponds was paved with bricks made of loam soil (using straw as binding material), after removing all vegetation on the pond bottom and banks. The pond was then filled to a depth of 1.2 m and the loss of water determined. The seepage rate in the ponds before and after the experiment was about the same (10–12 m3). The total cost of the experiment was 18 J.D. (180 J.D. per dunam), which equals the cost of constructing a new pond.
In another experiment a nursery pond was lined with plastic film (0.08 mm thick) after clearing all the vegetation and levelling and rolling the pond bottom and embankments. A herbicide was sprayed in the pond before laying the film. It is expected that there will be no seepage from the pond, but as the work was still in progress when the expert left the country, it is not possible to report on the final results. The cost of the experiment was as follows:
| J.D. | ||||
| Levelling | 242.5 | man-days | 97.0 | |
| Earth work | 57.0 | " | 22.8 | |
| Rolling | 4.0 | " | 1.6 | |
| Repairing outlet | 12.0 | " | 5.6 | |
| Plastic film 130 kg × 330 fils | 42.9 | |||
| Total | 169.9 | |||
A further expense of about 40 J.D. is expected to be incurred for transportation and laying of earth over the plastic film. The total cost would then be about 210 J.D. per dunam, which is equal to the highest cost of constructing a new pond.
In view of the high cost involved, it is not considered advisable to conduct any further experiments in improving these ponds. The funds could more profitably be used for constructing new ponds in a more favourable area.
Attempts were made by the expert to demonstrate methods of breeding common carp and growing fry and fingerlings. Seventeen male and 11 female fish in good condition were introduced in three breeding ponds on 19 April 1966 when the water temperature was 28°C and the next day they spawned. The eggs hatched out in seven days. As the hatchlings were not transferred to nursery ponds as instructed and the fishermen did not collect them with care, some avoidable mortality occurred. The rearing of fry was demonstrated with about 2,900 fry of an average weight of 5 g. Yellow corn was used as supplemental feed. In the first two months, 100 kg of the feed was given every month, the third month 75 kg and thereafter 50 kg each for two months. The fry attained an average weight of 60 g at the end of five months of rearing.
With a view to selecting a suitable site for a new experimental fish farm, seepage studies were made at the Faraa and Deir Alla Agricultural Station farm areas with the assistance of the Soil Laboratory at the Central Water Authority. The results are summarized below:
| No. of test | Seepage cm/hr | cu m/dunam | |
| Deir Alla | 1 2 | 0.13 0.14 | 31.25 33.60 |
| Faraa | 1 2 3 | 0.18 0.55 0.36 | 43.20 137.50 86.40 |
Even though the seepage rate is high in both areas, Deir Alla has comparatively better soil. However, before a decision is made to build an experimental farm here, it is necessary to conduct further studies and if necessary the construction and operation of a trial pond.
As there was a very large number of common carp and tilapia fingerlings in the nursery ponds at W. Yabis Fish Farm and in the irrigation reservoir at W. Faraa Agricultural Station, it was decided to conduct preliminary stocking experiments using these.
The Ziglab Dam impoundment was stocked with 700 carp and 100 tilapia fingerlings, weighing on an average 40 g and 100 g respectively. Periodic sampling showed an average weight increment of 11 g per fish in 20 days.
Seven circular cement tanks (12 sq m area each) in the farm of Mr. E. Hamarneh were stocked with 80 fingerlings of carp (average weight 57 g) and 61 fingerlings of tilapia. It was not possible to obtain information on the growth or survival of these fingerlings.
In view of the possible special significance of running-water fish culture in Jordan (see page 10) it was decided to conduct pilot studies. The Sukhneh Spring was selected for the initial experiments.
It has an average discharge rate of about 170 l/sec and a constant water temperature between 20 and 22°C. The chemical analysis of water, conducted by the Central Water Authority on 2 October 1960 gave the following results.
| E.C.Omhos at 25°C | Total dissolved salts ppm | Ca** | Mg** | Na** | K* | CL' | SO4 | CO3 | HCO3 | Total cation | Na% | pH |
| Milliequivalent per l | ||||||||||||
| 0.615 | 394 | 2.40 | 1.70 | 2.20 | - | 2.00 | 0.75 | 0.05 | 3.50 | 6.30 | 34.9 | 8 |
The experimental pond was constructed about 200 metres below the main spring in the farm of Mr. N. Shasham along the Sukhneh Spring Canal, according to the design prepared by Mr. V. Sheric, Engineer, “Energoproject”, Amman. The pond has a surface area of 7.36 sq m and a depth of 1.70 m. It is built of cement concrete with reinforcement iron bars of 8 mm placed every 15 cm. A gate was constructed on the main canal to divert the water to the pond.
The pond was stocked at the beginning of October 1966, with 800 one-year old common carp from the ponds in W. Faraa Agricultural Station, weighing on an average about 100 g and 107 tilapia. The mortality of carp during the fishing and transportation was about 5 percent and that of tilapia about 30 percent. The rate of stocking was 100 carp and 10 tilapia per sq m. Immediately after stocking it rained, and the water remained muddy for about a week.
Feeding was started a week after stocking, with pellets manufactured by the Provimi Feed Co. in Jordan according to the following formula furnished by the expert:
| Percent | |
| “Provimi 55” | 20 |
| Cotton-seed meal | 18 |
| Soybean meal | 20 |
| Yellow corn | 20 |
| Wheat | 15 |
| Milk powder | 4 |
| Brewer's yeast | 3 |
| Total | 100 |
The pellets were made by using 5 percent of molasses as a binding agent. The total protein content of the feed is 30.1 percent. The pellets retain their form in water for 30 to 45 minutes. Feeding was done thrice a day: morning, noon and afternoon, at the rate of 6 kg of feed per day to start with. Regular observations of water quality, etc. were planned, but had to be discontinued on account of the termination of the expert's assignment. On sampling, it was found that the fish had attained on an average 30 g per month or 1 g per day.
During the expert's assignment, preliminary experiments were conducted in the culture of rainbow trout. Badan Spring near Nablus and Sukhneh Spring near Zarqa were considered the most suitable sites for such experiments. Badan Spring has an average water flow of 81 l/sec (maximum: 151 l/sec; minimum: 27 l/sec), total dissolved salts 325 ppm, Cl' about 1.05 ppm and pH 8. The Sukhneh has an average water flow of 170 l/sec (maximum: 301 l/sec; minimum: 140 l/sec), total dissolved salts 394 ppm, Cl' 2.00 ppm and pH 8. The pools formed by the water measurement weir at the Badan Spring and the Sukhneh Spring canal of the farm of Mr. N. Shashaa were used for the experiments.
Eyed eggs were imported from the Yugoslav Hatchery in Gostivar of the Fisheries Institute in Skopje and from the Manchester National Hatchery of the U.S. Fish and Wildlife Service in Manchester, Iowa, U.S.A. The shipment of eggs from Yugoslavia was received on 23 March 1966 and that from the U.S.A. on 2 April 1966. Both were late-hatched eggs and not in good condition.
They were placed in the two springs. In Sukhneh Spring where about ⅓ of the consignment was introduced all the eggs died. In Badan Spring, the eyed eggs hatched after three to six days, as shown below:
| Strain of trout | Date of arrival | Number of eggs | Days taken for hatching | Mortality Percent | Remarks |
| “Vrutok” (Yugoslavia) | 23.3.1966 | 10,000 | 3 | 99 | More than 70 percent of eggs were dead on arrival |
| “Donaldson” (U.S.A.) | 2.4.1966 | 13,000 | 6 | 70 | More than 40 percent of eggs were dead on arrival |
Though the number of hatchlings was small, the experiment was continued to study the growth of fry under local conditions. Feeding was started after five days for the “Vrutok” strain and after 15 days for the “Donaldson” strain. Food for the first 30 days consisted of 50 percent liver and 50 percent spleen. Thereafter they were fed on a mixture of liver and spleen (60 percent) and “Provimi” concentrate (40 percent). The feed was ground and sieved through a mosquito screen. In the beginning feeding was done five to six times each day, but it was later reduced to three times per day. The fry attained a weight of about 5 g by December. A total of 26,000 kg of feed were used in the experiment and the food conversion coefficient was estimated to be 2.2.
On 1 October 1966 all the fish were transferred to the Sukhneh Springs and introduced in the running-water pond constructed there (see page 13) for further rearing.
