by
M.I. AL-HAMED
Division of Hydrobiology and Fisheries
Ministry of Agriculture
Baghdad, Iraq
Abstract
Fish culture in ponds was started for the first time in Iraq in 1955. The carp, Cyprinus carpio, is the principal species cultivated; but some Barbus species are also reared separately or in combination with carp.
Feeding experiments indicated that carp production increased four to five times by using corn, barley or cotton seed meal. About one ton of any of the mentioned feeds per donum (1 donum = 2,500 sq m) per season produced 350 to 450 kg while that without feeding did not exceed 86 kg per donum.
Commercial fertilizers 13-13-5-1.5, N-P-K trace elements and 8-9-2, N-P-K, increased the productivity from 200 to 250 kg of fish per donum on an average.
Inorganic fertilizers 13-13-5-1.5 or 8-9-2 with barley increased carp production from 6.7 to 7.6 times. Best growth was obtained when stocking density was 600 fish per donum. Fertilization together with the herbicides 2,4-D, 2,4,5-T, and sodium arsenite were effectively used for weeds control.
LA CARPICULTURE DANS LA REPUBLIQUE D'IRAK
Résumé
En Irak, la pisciculture en étang a débuté en 1955. La principale espèce élevée est la carpe, Cyprinus carpio; toutefois, des essais ont également été faits avec l'espèce Barbus, soit en élevage séparé, soit en association avec les carpes.
Des expériences d'alimentation indiquent que la production de carpes a quadruplé, voire même quintuplé, lorsque les poissons sont nourris avec de la farine de blé, d'orge ou de graine de coton. En fournissant une tonne de l'un quelconque de ces aliments par donum (1 donum = 2 500 m2) et par campagne, on a obtenu une production allant de 350 à 450 kg, alors que sans alimentation extérieure la production ne dépassait pas 86 kg par donum.
L'emploi d'engrais commerciaux (13-13-5-1,5, N-P-K-oligoéléments et 8-9-2, N-P-K) a permis de porter le rendement de 200 à 250 kg de poisson par donum en moyenne.
En employant des engrais inorganiques 13-13-5-1,5 ou 8-9-2, avec une nourriture à base d'orge, on a pu multiplier la production de carpes par des chiffres allant de 6,7 à 7,6. Les meilleurs résultat ont été obtenus avec une densité de peuplement de 600 poissons par donum. En utilisant, en association avec les engrais, des herbicides (2,4-D, 2,4,5-T et arsénite de sodium), on a obtenu de bons résultats dans la lutte contre les plantes adventices.
LA CARPICULTURA EN LA REPUBLICA DEL IRAK
Extracto
La piscicultura en estanques fue iniciada por vez primera en Irak en 1955. La principal especie cultivada es la carpa, Cyprinus carpio, aunque también, se cultivan independientemente, o en combinación con la carpa, algunas especies de Barbus.
Los experimentos referentes a la alimentación indicaron que la producción de carpas aumentó de 4 a 5 veces utilizando harina de maíz, cebada o semilla de algodón. Una tonelada, aproximadamente, de cualquiera de los alimentos mencionados por donum (1 donum = 2.500 m2) y por temporada dió una producción de 350 a 450 Kg, en tanto que sin alimentación ésta no excedió de 86 kg por donum.
Los fertilizantes comerciales 13-13-5-1,5, N-P-K oligoelementos y 8-9-2, N-P-K hicieron aumentar la productividad como promedio desde 200 hasta 250 Kg de pescado por donum.
Los fertilizantes inorgánicos 13-13-5-1,5 u 8-9-2 con cebada aumentaron la producción de carpa de 6,7 a 7,6 veces. El mejor crecimiento se obtuvo cuando la densidad de población era de 600 peces por donum. La fertilización junto con los herbicidas 2,4-D, 2,4,5-T y arsenito sódico se utilizaron con eficacia en la lucha contra las plantas adventicias.
Iraq, through its over 20,000 square kilometers of inland waters, produces a wide variety of fresh-water fishes, most of which belong to the carp family. Statistical data collected by the fishery specialists show that the production of these waters does not exceed 30,000 metric tons per year, far below the demand for local consumption. However, biological investigations carried out on inland waters showed that there is a high potential for increase of fish production in the future if proper management and adequate protection measures are applied.
Because of the shortage in animal protein production, the Government of Iraq is fostering a program to increase its production. This program aims at encouraging fish culture in ponds to increase the protein in the population's diet and to counterbalance the decrease in catches from natural waters. This decrease in catches is attributed to several factors, foremost amongst which are improper fishing practices, rivers and stream obstructions, soil erosion and silting and intensive fishery.
The object of this paper is to summarize pertinent findings derived from the experiments that have been carried out on carp (Cyprinus carpio) culture in the Republic of Iraq.
Fish culture in ponds started for the first time in Iraq in 1955 with an experimental fish farm of 32 ponds at the Zafraniyah Experimental Farm, 16 kilometers south of Baghdad. Since then, these ponds have been increased to 55, covering a total area of 15 hectares of water. These ponds are operated by the Division of Hydrobiology and Fisheries of the Ministry of Agriculture. About twice this area of ponds have been built and operated by the Local Administration of the Ministry of Interior.
In the ten years from 1955 to 1965, the Division of Hydrobiology and Fisheries provided technical assistance to farmers' cooperatives, individual farmers, and land owners for the construction of over 100 ponds, that covered a total area of 30 hectares.
The carp, Cyprinus carpio, is the principal species cultivated in ponds throughout the country. However, the following Barbus species are being tested to evaluate their suitability for pond culture: Barbus grypus, B. xanthopterus, B. luteus, B. sharpeyi.
Each of these species was first tested in a separate pond to study its biology and behaviour and to find out whether it will reproduce in ponds under ordinary pond conditions. After two years it was found that these species failed to spawn in ponds. Because of the high commercial value of these species they were kept separately and in combination with carp in independent ponds for the purpose of evaluating their production in fertilized waters and with supplemental feeding.
These experiments will be conducted for several years before selecting the species that are best adapted to pond fish culture.
A preliminary experiment on the artificial propagation of these species was also conducted in the spring of 1965, without reaching a positive conclusion. It is therefore necessary to resume this work in the future.
As no definite results have as yet been obtained on the suitability of any of these four Barbus species for pond culture, the present paper will deal with the cultivation of common carp only.
Two strains of scaled common carp were introduced from Indonesia (punten carp) and Holland (Japanese multi-colour carp) and transferred immediately into ponds. The fry were left in ponds for one year without supplemental feeding and with occasional fertilization. During the second year of life inorganic fertilizers and supplemental feeds were applied as needed to induce rapid growth (Al-Hamed, 1960).
In the spring of the second year fish spawned in ponds and the fry were left in the same ponds until they reached fingerling size before being stocked in other ponds for experimental purposes.
The experiments on carp at the Zafraniyah Fish Culture Station started in the summer of 1959. Investigations were carried out on supplemental feeding, fertilization, rate of stocking, weed control, mixed culture with the Barbus species and other interrelated subjects. The findings of these preliminary experiments are recorded here.
Preliminary experiments on the effect of various types of supplemental feeds on carp production in ponds have been conducted in ponds of ¼ donum size, i.e. 625m2 (1 donum = 2,500 m2 = approximately 0.6 acre). The results indicated that corn, barley and cotton seed meal increased carp production from four to five times as compared with ponds receiving no supplemental feeds (Al-Hamed, 1961). These results are tentative pending further experimentation on the suitability of various other types of feeds, and the level of feeding under different climatic conditions. However, the production of carp receiving approximately one ton of any of the above mentioned feeds during the experiment period (one vegetative period) ranged from 350 to 450 kilograms per donum, while the production in those ponds receiving no supplemental feeds did not exceed 86 kilograms per donum (Al-Hamed, 1961). These figures indicate that carp production in ponds can be greatly increased provided the proper types and amounts of supplemental feeds are given.
As fish culture in ponds is a recently established industry in this country, the problems of pond fertilization which arise from differences of water quality, bottom soils and other factors require further research. The complexity of the problems was reflected in the wide variation of fish production among several unfertilized ponds in one area and in different areas having similar climatic conditions. Moreover, it was observed that unfertilized ponds in some instances gave higher production than fertilized ones. Therefore, it has to be stated that the preliminary results so far arrived at are insufficient to draw specific conclusions. However, the results of preliminary experiments obtained at Zafraniyah Fish Culture Station indicated that commercial fertilizers, 13-13-5-1.5, N-P-K trace elements and 8-9-2, N-P-K, increased the productivity from 200 to 250 kilograms of fish per donum (i.e. from 800 to 1,000 kg/ha). Further experiments on the fertilizer requirements with water of different qualities are currently in progress.
The first experiment with inorganic fertilizers and supplemental feeds was conducted in the summer of 1960. The results indicated that the use of superphosphate together with barley or cotton seed meal had a more pronounced effect on the growth and production of carp than either one used separately (Al-Hamed, 1961). With this in mind, a combined experiment with modified levels of fertilizer applications with barley was conducted in summer 1965. Five ponds of ¼ donum (625 m2) in size were stocked with a definite number and weight of fish in April 1965 and were given the following treatments:
Superphosphate and cotton seed meal
Superphosphate and barley
8-9-2, N-P-K and barley
13-13-5-1.5, N-P-K trace elements and barley
Control (without treatment)
At the end of September 1965 the ponds were drained and the fish were counted and weighed. The results are given in the following table.
Table I
The effect of fertilization and supplemental feeding on carp
production in ponds
| Pond No. | Treatment | Yield/kg/donum | kg/ha |
| 1 | Sup. and cotton seed meal | 321 | 1,284 |
| 2 | Sup. and barley | 352 | 1,408 |
| 3 | 8-9-2 and barley | 646 | 2,584 |
| 4 | 13-13-5-1.5 and barley | 720 | 2,880 |
| 5 | Control | 96 | 384 |
As shown in Table I, the use of commercial fertilizers, 8-9-2 and 13-13-5-1.5 with barley, increased carp production to almost twice that obtained from superphosphate and barley or cotton seed meal, and 6.7 to 7.6 times that of the control. It may be concluded that the use of fertilizers together with supplemental feeds leads to much higher production than either one alone. Therefore, more emphasis is given to this type of research in order to establish the best combinations of both fertilizers and feeds which give higher economical production.
Preliminary experiments on stocking densities were carried out in ponds of ¼ donum (625 m2) size. Four ponds were stocked in March 1964 with 150, 200, 250 and 300 fish of an average weight of 130 grams. At the end of October of the same year, ponds were drained and the fish counted and weighed. The results are given in the following table.
Table II
The effect of stocking densities on the growth of carp in ponds
| Pond No. | No. fish | Av. wt. fish | Total weight produced | |||
| per pond | per donum | (g) | (kg) | (kg/donum) | (kg/ha) | |
| 1 | 150 | 600 | 900 | 135 | 540 | 2,160 |
| 2 | 200 | 800 | 740 | 148 | 592 | 2,368 |
| 3 | 250 | 1,000 | 600 | 150 | 600 | 2,400 |
| 4 | 300 | 1,200 | 490 | 147 | 588 | 2,350 |
As shown in Table II, the stocking rate of 1,000 fish per donum (4,000 per ha) gave the highest production (600 kilograms per donum, 2,400 kg/ha) and that of 600 fish per donum (2,400 per ha) gave the lowest. As a fish of 900 grams is more profitable and desirable to the consumers than that of 600 grams the former figure (600 fish per donum, 2,400 per ha) is the recommendation given to pond owners at the present time.
Aquatic vegetation is not a sericus problem in carp ponds when constructed and managed according to the latest techniques. Otherwise, it poses a problem especially when the ponds are shallow and not adequately fertilized. Reeds (Phragmites) and cattails (Typha) are the dominant obnoxious emergent plants in such ponds. When they are once established in a pond they grow very rapidly so that complete eradication is impossible in spite of continued fertilization and control measures with plant growth-regulators such as 2,4-D and 2,4,5-T. However, in an experiment at the Zafraniyah Fish Culture Station, 2,4-D ester, with tributylphosphate as a co-solvent and kerosene as carrier, has been found to be effective in eradicating cattails when used in 0.5 to 1.0 percent solution. Two sprays of this solution, the first in April and the second in August, proved to be of great value in eliminating these weeds.
To control Phragmites 2,4-D tributylphosphate-kerosene solution was effective, but spraying with 1.0 percent 2,4,5-T solution was more effective in eradicating them.
Submerged aquatic plants are less important than emergents, but sometimes pose a problem when the pond is underpopulated and not properly fertilized. Proper fertilization and adequate stocking rate proved to be effective in controlling such plants. However, sodium arsenite in a concentration of 3 to 4 ppm was found to be very effective in controlling hornwort (Ceratophyllum), water milfoil (Myriophyllum), pond weed (Potamogeton) and naiad (Naias).
These results, obtained from preliminary experiments, are not sufficient to make recommendations on the more effective methods of weed control until further experiments on different methods and materials are conducted.
The results of a survey of existing carp ponds throughout the country indicated that many ponds fail to produce a satisfactory yield. The principal causes of failure have been investigated and are as follows:
(i) Stocking rate
It is a common occurrence to find a pond of an area less than one donum (0.25 ha) stocked with more than three thousand fish. The owners of such ponds complain that fishes do not grow well. For solving such a problem, demonstration ponds were built in certain districts to demonstrate to the pond owners the effect of stocking rate on the growth of carp in both fertilized and unfertilized ponds.
(ii) Undesirable wild fish
One of the common causes of failure in carp culture is the existence of a great number of wild fish species entering the ponds with the water supply. Results of preliminary experiments revealed that 3 to 3.5 ppm of Malathien 50 percent was effective in eliminating all the wild fishes without any harmful effect on carp (Al-Hamed, 1965a, unpublished). This material, together with the use of a screening system on the water supply inlet pipes, was recommended to pond owners.
(iii) Pond construction
Proper construction of ponds has a pronounced influence on their successful management. This means that certain requirements and features should necessarily be fulfilled before selecting the pond site and before pond construction (Lawrence, 1949; Al-Hamed, 1965b and others). Many ponds have been constructed without paying any attention to such requirements. Therefore, they failed to be economically profitable. Assistance in selecting pond sites and planning the layout of the ponds was given by the technical staff of the Division of Hydrobiology and Fisheries. As a result of this assistance, the majority of ponds constructed in recent years meet the necessary requirements.
(iv) Pond fertilization
Farmers know that profitable farming requires proper fertilization, but they do not understand and believe that ponds must also be fertilized for higher fish production. Therefore, the majority of the existing ponds are unfertilized and subsequently, they fail to produce profitable yields.
(v) Muddy water
During the spawning period, the flood water which is heavily loaded with silt poses a serious problem for successful spawning. The deposition of silt on eggs affects hatching of a great proportion of the eggs. Investigations carried out in this respect revealed that the construction of desilting tank or pond is necessary for those fish farms that follow a complete system of fish culture.
Natural lakes and irrigation and flood water relief reservoirs have recently been utilized for carp cultivation. Two lakes, Hammar and Saniyah, and two reservoirs, Habbaniyah and Tharthar, were stocked with carp fingerlings for the first time in 1960. Since then the fisheries authority have continued to release carp fingerlings in lakes and reservoirs for increasing their fish productivity.
Two years after the first stocking, fishes were caught for growth study. During this period measures were taken to prohibit fishing, so that the carp could grow and reproduce naturally. Preliminary results indicate that carp released in lakes grew faster (1 to 1.5 kg in two years) than those released in reservoirs (700 to 1,000 g). Further investigations on the growth rate, environmental suitability and reproductive potential of carp in natural waters are in progress.
Al-Hamed, M.I., 1960 Introduction of carp Cyprinus carpio L., to Iraq. Iraqi J.agric.Res., 1(2):14–23
Al-Hamed, M.I., 1961 The effect of inorganic materials on the growth of carp. Iraqi J.agric.Res., 2(1):27–32
Al-Hamed, M.I., 1965a Toxicity of malathion 50 percent to various fresh-water fishes of Iraq. (Unpublished MS)
Al-Hamed, M.I., 1965b Fish culture in ponds. Tech.Bull.Dep.agric.Res., (21):53 p.
Lawrence, J.M., 1949 Construction of farm fish ponds. Circ.Ala.agric.Exp.Stn., (95):55 p.
