As development of warmwater fisheries cannot be based on regularly imported fry, and proper control of purity, good health and high genetic value cannot be guaranteed, every country must be able to produce her own fish seed requirement.
In addition to maintaining a broodstock of high genetic value, and the production of fingerlings according to the requirements of the commercial food fish production, an extension centre is also needed for dissemination of information on up-to-date fish production methods by demonstrations and training courses conducted by qualified extension officers. All these activities can be concentrated in a central warmwater fish seed production and demonstration centre.
Such a centre has to be designed according to the revised development plans of the Animal Husbandry Department so as to provide some 100 000 fingerlings by the end of the fifth Five-Year Plan and some 250 000 fingerlings in the long term. These objectives could have been easily achieved if only common carp were used in a monoculture system. However, taking into account that Bhutan has recently become a net importer of cereals and that the per caput income is relatively low, it is not feasible to establish a carp monoculture based on more or less intensive feeding.
When introducing polyculture, common carp, grass carp and silver carp should play equally important roles by utilizing the available natural food resources; and catla, bighead and rohu should fill the gaps as secondary species of a well balanced polyculture.
Naturally, not all of these species should be raised in all of the private ponds, but the centre must maintain a proper number of selected breeders from all of the species in the broodstock ponds. Because the natural spawning of most of the above fish species cannot be achieved, moreover, induced breeding methods will have to be applied. For this, a construction of a simple but flexible hatchery is recommended. The hatchery should also include adequate larval-rearing facilities.
After the brief period of larval-rearing, swim-up fry should be stocked to well prepared small nursery ponds, where the fry will be nursed up to a size of 2–3 cm. Although it is recommended to harvest the nursery ponds after the fry reach the proper size and then stock them in bigger fingerling ponds, a part of the nursed fry could be restocked in the harvested ponds at the end of the breeding season. Fingerling ponds should be stocked in polyculture. At this stage it is also possible to introduce integration with other animal husbandry practices (preferably with pig and/or duck production), as stable manure is not readily available and imported fertilizers are too expensive to be used for regular pond fertilization. The centre also has to demonstrate, therefore, integrated fish farming methods to the farmers.
Thus, the centre must have the following basic facilities:
broodstock ponds
multispecies hatchery
nursery ponds
fingerling ponds (with pig stalls)
auxiliary facilities, e.g., residence for staff, office, field laboratory, store, garage, workshop and public utilities (e.g., drinking water supply, electric power, telephone, access road, fence, etc.)
When elaborating the basic concept of the centre, all these facilities have to be taken into account. However, it is possible to implement the construction in at least two phases, the fingerling requirement of the country is low at the beginning and it increases only step-by-step. Therefore, it is recommended that the construction of the broodstock ponds, the hatchery, the nursery ponds and the required extent of the auxiliary facilities be completed in the first phase and the construction of the fingerling ponds be left to the second phase of development. In such a case the land acquisition costs, as well as the capital investment, could be spread into two more or less equal shares.
1. SITE SELECTION
Although the southern reaches of all Bhutanese rivers offer potential sites for the warmwater fish seed production and demonstration centre, the areas of Gaylegphug, Sarbhang and Chirang were selected by the Government for closer survey, because of their central location, presence of infrastructure facilities, and the existence of operational private ponds in the neighbourhood.
The Mission investigated five of the possible sites in the above region, which offer some 3–5 ha suitable for pond construction, as well as possibilities for future expansion. The findings of this field survey are given in Table A.1.
Table A.1
QUALIFICATION OF POSSIBLE SITES INVESTIGATED
| Denomination | Chirang | Sarbhang | Khalikhola | Phonphone | Gaylegphug |
| Area | limited | limited | enough | enough | enough |
| Topography | bad | bad | good | fair | fair |
| Soil texture | fair | good | fair | good | excellent |
| Water supply | temporary | temporary | excellent | good | excellent |
| Access road | close | close | very far | very far | close |
| Power line | close | close | very far | very far | close |
Chirang and Sarbhang were rejected because of their bad water supply and limited suitable area, Khalikhola and Phonphone were rejected because of their difficult access (during the monsoon period, the traffic cannot be maintained across the swollen river). Thus, a site at Gaylegphug was selected.
This site has the following advantages:
plenty of topographically-suitable area is available for present and future development;
the soil is an excellent, watertight, deep clay or silty clay; excavations down to 100–120 cm are possible without encountering gravel or rock layers;
water supply by gravity is continuous (even the hatchery will not need pumping);
closeness of a sizeable township (which is a district centre) ensures accessibility to the existing road, power and telephone network, as well as drinking water supply;
housing facilities for a part of the staff might be solved more economically within the town area.
There is only one disadvantage, namely:
the area selected has traditionally been used for agriculture purposes. The entire area is a terraced paddy field, therefore, acquiring the land may be difficult and expensive.
In order to avoid problems arising at a later date, the site selected was shown to the Dzongda of Gaylegphug, who in consultation with the local leaders involved, approved the selection.
After approval, a topographic survey was carried out, covering not only the area required, but also the area of possible future development (altogether 8.4 ha).
1.1 Location
The site selected is 0.6 km southeast from the centre of Gaylegphug, lying roughly 210 m above sea level. Its northwest corner is fairly rugged, the southeast part flatter. There is 5 m vertical difference between the northwest and southeast corners. The topographic survey was made in a relative scale, taking the crown of a concrete gate on the main irrigation canal in the northwest corner as a reference point (10 000 m relative elevation).
1.2 Water Source
Irrigation water is supplied to the territory by an existing main irrigation canal delivering the diverted water of the Mao River to irrigated agricultural areas east and southeast of the town. The flow rate of the main canal in the second half of May (in the dry season) was 0.25–0.35 m3/sec, and it was only partly utilized by the farmers concerned. The estimated flow rate in the monsoon season may reach 1.8–2.0 m3/sec, based on the dimension of the existing structures.
There are two concrete plastered masonry gates within 25 m distance on the main canal at the northwest corner of the area. The first has a 3.7-m wide and 0.65-m high opening, the bottom being at 9.90 m relative elevation. The second has a 4.4-m wide and 1.0-m high opening with the bottom at 9.01 m relative elevation (the crown of this gate was taken as a reference point, as this structure was in better condition than the weathered first gate). Thus there is a drop of almost 0.9 m in the water level of the canal at the first gate.
The existing secondary irrigation ditches serving the area are supplied with water from above the first structure. The minimum water level of the main canal (10.00 m relative elevation) extends over the entire area with at least 0.5 m, except for a 0.4-ha area in the northeast corner of the territory.
From north, northeast and east, the site is bordered by a deep, natural, temporary watercourse, which serves as a recipient of excess waters. As this watercourse is 1.5–2.0 m deeper than the adjacent areas, it offers an excellent drainage facility for the ponds to be constructed. On the west, the area is bordered by a deep artificial canal functioning from the main irrigation canal just before the second gate. This canal brings water to more distant irrigated areas; its bottom is some 1.0–2.0 m deeper than the adjacent areas, and therefore it can also be taken into consideration as a recipient.
1.3 Soil
The soil texture of the area is exceptionally favourable. The heavy, thick, grey clay (or, at least, loamy clay) soil is used as raw material in an adjacent brick factory. The watertight layer is at least 1–1.5 m deep, as shown on the profiles exposed on the west, north and east borders of the area. Coarse gravel and rock are to be found only below 2-m depth.
The stony river bed is separated from the selected site by a wide terrace of agricultural area having also heavy clay soil. This stretch of land grants safe protection against possible alternations of the river course.
2. DESIGN OF THE CENTRE
2.1 Design of the Ponds
Taking into account the topography of the selected site, the following ponds were lined out:
4 broodstock ponds (min. 0.21, max. 0.27 ha)
5 nursery ponds (min. 0.29, max. 0.37 ha)
7 fingerling ponds (min. 0.26, max. 0.51 ha)
Total net surface area (water surface) of the ponds is 5.04 ha, while the total gross area of the site is 8.4 ha. Detailed data of the ponds are given in Table A.2.
The ponds have a slightly elongated contour, their bottom sloping toward the outlet structure thus allowing complete drainage. Material of the dikes is dug out from the higher portions of the pond bottoms, retaining, however, at least, 0.5 percent slope. The water depth of the ponds is at least 1.5 m at the drainage structures. The crown of the dikes is 0.5 m higher than the water level, their inner slope is 1:2 and their outer slope is 1:1.5. Except for those 5-m wide dikes on which vehicle traffic is expected and/or an irrigation canal is running, the crown of the dikes is 2 m wide.
It is planned to construct the irrigation canals with vertical masonry walls laid on rock and thin concrete base, and plastered from inside with thick concrete (this is a traditional construction method in the country and especially advantageous for dike of fish ponds). As the dike system follows the marked slopes of the terrain, bottom steps have to be constructed at several places (as shown on the longitudinal sections of the irrigation canals. Dimensions of the irrigation canals (60 × 60 m by the main canal and 50 × 50 m by the laterals) will allow rapid flooding of the ponds; all of them might be filled within 8–14 h (3 ponds might be filled simultaneously).
Feeder structures are similar to the irrigation canals. Three pairs of grooves, constructed in their side, allow watertight closure by wooden slabs and also screening of the water.
The canal itself must also be supplied with a pair of grooves after each inlet in order to withhold the water and divert it to the pond being filled. Starting from the inlet structure down to the bottom of the pond, the slope of the dike has to be lined, and also at least 1 m2 of the bottom, below the inlet structure to prevent erosion. The lining can be thin concrete or rock laid in thin concrete (both on gravel fill).
It is not planned to line the drainage canals, except for those sections where the outlet structures drain water. The drainage canals are 0.5 m deeper than the deepest parts of the pond bottoms. The drainage structures of the ponds are specially designed monks comprising a strong masonry monk-tower, prefabricated RCC span tubes and a masonry catch-box connected to the drainage canal. The monk-tower has to have three pairs of grooves (two for wooden slabs for watertight closure and one for a screen to retain fish), the pond bottom and the slope of the dike have to be lined in its vicinity.
Specifications of the structures of the canal system are given in Table A.3.
Maximal annual water requirement of the centre (after the fingerling ponds are also completed and reckoning with two harvests and stockings annually) will be as follows:
| - | filling the ponds | (2 × 5.04 ha × 15 000 m3) | = | 151 200 m3 |
| - | evaporation losses | (5.04 ha × 20 000 m3) | = | 100 800 m3 |
| - | seepage losses | (5.04 ha × 10 000 m3) | = | 50 400 m3 |
| Total | 302 400 m3 |
Table A.2
SPECIFICATION OF THE PONDS
| Symbol | Net water
surface (m2) | Dike level (m rel.) | Water level (m rel.) | Deepest ground level (m rel.) |
| Phase 1 | ||||
| Broodstock ponds | ||||
| B-1 | 2 590 | 9.50 | 9.00 | 7.50 |
| B-2 | 2 650 | 9.50 | 9.00 | 7.60 |
| B-3 | 2 070 | 9.00 | 8.50 | 6.90 |
| B-4 | 2 660 | 9.00 | 8.50 | 7.10 |
| Total | 9 970 | - | - | - |
| Nursery ponds | ||||
| N-1 | 3 720 | 9.00 | 8.50 | 7.10 |
| N-2 | 2 970 | 8.50 | 8.00 | 6.40 |
| N-3 | 3 150 | 8.20 | 7.70 | 6.20 |
| N-4 | 2 900 | 8.10 | 7.60 | 6.00 |
| N-5 | 2 410 | 7.50 | 7.00 | 5.60 |
| Total | 15 150 | - | - | - |
| Total of Phase 1 | 25 120 | - | - | - |
| Phase 2 | ||||
| Fingerling ponds | ||||
| F-1 | 3 160 | 8.10 | 7.60 | 6.30 |
| F-2 | 3 330 | 7.50 | 7.00 | 5.40 |
| F-3 | 3 680 | 7.20 | 6.70 | 5.10 |
| F-4 | 5 140 | 7.30 | 6.80 | 5.40 |
| F-5 | 3 930 | 8.20 | 7.70 | 6.10 |
| F-6 | 2 570 | 8.30 | 7.80 | 6.30 |
| F-7 | 3 420 | 7.70 | 7.20 | 5.70 |
| Total of Phase 2 | 25 230 | - | - | - |
| Grand total | 50 350 | - | - | - |
Table A.3
SPECIFICATION OF THE STRUCTURES OF THE CANAL SYSTEM
| Code | Denomination | Crown level (m rel.) | Bottom level (m rel.) | |
| Phase 1 | ||||
| Irrigation canal I-1 | ||||
| 1-0 | Gate with screen | 0+000 | 10.60 | 9.90 |
| 1–1 | Gravel filter | 0+005/12 | 10.60 | 9.90 |
| 1–2 | Function with gates | 0+014 | 10.50 | 9.90 |
| 1–3 | Culvert 050 cm | 0+014/20 | 10.50 | 9.90 |
| 1–4 | Feeder with gate | 0+053 | 9.50 | 8.90 |
| 1–5 | Function with gates | 0+151 | 9.50 | 8.85 |
| 1–6 | Culvert 050 cm | 0+131/135 | 9.50 | 8.85 |
| 1–7 | Feeder with gate | 0+147 | 9.00 | 8.50 |
| 1–8 | Feeder with gate | 0+232 | 8.50 | 8.00 |
| 1–9 | Feeder with gate | 0+269 | 8.20 | 7.70 |
| 1–10 | Feeder with gate | 0+312 | 8.10 | 7.60 |
| 1–11 | Feeder with gate | 0+347 | 8.10 | 7.58 |
| Irrigation canal I-11 | ||||
| 11-1 | Culvert 050 cm | 0+075/81 | 10.48 | 9.88 |
| 11-2 | Culvert 050 cm | 0+098/104 | 10.45 | 9.85 |
| 11-3 | Feeder with gate | 0+107 | 10.45 | 9.85 |
| 11-4 | Feeder with gate | 0+127 | 9.00 | 8.50 |
| Irrigation canal I-12 | ||||
| 12-1 | Feeder with gate | 0+008 | 9.50 | 8.85 |
| 12-2 | Feeder with gate | 0+125 | 9.00 | 8.50 |
| Drainage canal D-1 | ||||
| 0–1 | Outlet with catchbox | 0+028 | 7.50 | 5.35/4.85 |
| 0–2 | Outlet with catchbox | 0+075 | 8.10 | 5.85/5.35 |
| 0–3 | Outlet with catchbox | 0+115 | 8.20 | 5.85/5.45 |
| 0–4 | Outlet with catchbox | 0+155 | 8.50 | 6.35/5.85 |
| 0–5 | Outlet with catchbox | 0+192 | 9.00 | 6.85/6.15 |
| 0–6 | Culvert 050 cm | 0+24/225 | - | 6.20 |
| 0–7 | Outlet with catchbox | 0+254 | 9.50 | 7.35/6.25 |
| 0–8 | Twin outlet with catchbox | 0+256 | 9.50/9.00 | 6.85/6.25 |
| 0–9 | Outlet with catchbox | 0+254 | 9.00 | 6.60/6.25 |
| Drainage canal D-2 | ||||
| 0–12 | Culvert 050 cm | 0+009/14 | - | 8.10 |
| 0–13 | Hatchery outlet | 0+032 | - | 8.30/8.15 |
| 0–14 | Outlet | 0+075 | - | 8.45/8.35 |
| Phase 2 | ||||
| Irrigation canal 1–11 | ||||
| 11–5 | Feeder with gate | 0+173 | 8.30 | 7.80 |
| 11–6 | Feeder with gate | 0+233 | 7.70 | 7.20 |
| Irrigation canal 1–12 | ||||
| 12–3 | Feeder with gate | 0+128 | 9.00 | 8.50 |
| 12–4 | Feeder with gate | 0+167 | 8.20 | 7.70 |
| 12–5 | Feeder with gate | 0+208 | 8.20 | 7.68 |
| 12–6 | Feeder with gate | 0+231 | 8.20 | 7.67 |
| 12–7 | Feeder with gate | 0+250 | 7.20 | 6.70 |
| Drainage canal D-1 | ||||
| 0–10 | Outlet with catchbox | 0+016 | 8.10 | 6.10/5.55 |
| 0–11 | Outlet with catchbox | 0+028 | 7.50 | 5.10/4.60 |
| Drainage canal D-3 | ||||
| 0–15 | Outlet with catchbox | 0+016 | 7.20 | 4.85/4.45 |
| 0–16 | Outlet with catchbox | 0+090 | 7.30 | 5.10/4.60 |
| 0–17 | Outlet with catchbox | 0+181 | 7.70 | 5.50/5.00 |
| 0–18 | Twin outlet with box | 0+245 | 8.30/8.20 | 6.00/5.50 |
Remarks: By outlet structures bottom level of both the drainpipe and the catchbox is given. By twin outlet structures the crown levels of the two monks are not necessarily equal
This annual requirement is equal to 9.6 1/sec continuous water discharge, which, when compared with the 250–350 1/sec discharge of the main canal (observed at the end of the dry season), is really negligible. The establishment of the centre, therefore, will have an adverse effect on the traditional irrigated farming in the vicinity.
It has to be noted, however, that the existing structures of the main canal are not adequate for sophisticated water management. Simultaneously with the construction of the pond system the existing two gates have to be redesigned and reconstructed, facilitating impounding also during the dry season in order to ensure a high enough water level for the operation of the hatchery's gravity water supply.
As the water of the main canal is actually the diverted water of the river, it might be contaminated with fish pathogens, parasites and even unwanted wild fish. Therefore, it is recommended to construct a coarse gravel filter where the water enters the centre, and a finer sand filter before the hatchery. This latter has to be constructed within a settling pond (which will also serve as a buffer reservoir), because during the hatching process the turbidity of the water may also result in heavy losses.
2.2 Design of the Hatchery
Broodstock of the centre (some 200 sexually mature males and females of six fish species) will be raised in the broodstock ponds in polyculture, but separated by sex in order to avoid unwanted natural spawning. Before the induced breeding, the broodstock ponds have to be harvested (preferably by netting), the best breeders must be selected and transported to the ward tanks constructed both outside and within the hatchery.
The outdoor ward tanks are 7 × 2.5 m; the indoor ward tanks are 1.5 × 2 m, and both types have 1.1 m water depth. Their bottom is gently sloping toward the discharge where it suddenly deepens to form a refuse channel for the fish, thus ensuring complete drainage. The ponds are drained by turn-pipes which also allow the desired water level in the tank to be maintained.
Breeding is induced by multiple injections of fish pituitary gland extract. Pituitary glands could be collected and preserved locally, using market fish, discarded breeders and discarded breeders candidates as donors. Ripe breeders are stripped, the eggs fertilized in plastic bowls. Fertilized eggs are hatched either in immersed incubators or in Zoug-jars. For the immersed incubators, an elongated twin tank has to be constructed in the hatchery, length of which is 7 m. The tank for incubators is 1 m wide, and the tank for larval-rearing devices is 1.5 m wide. The partition wall between the two sections must be lower than the parameter wall in order to allow larvae to swim through from the incubators to the larval-rearing devices. The Zoug-jars are mounted on the side wall of the ward tank.
Larval-rearing is carried out either in funnel-type or in box-type rearing devices within the hatchery, protected from the sun. The rearing lasts for 3–4 days depending on the fish species. When the yolk-sac of the larvae is absorbed, the swim-bladder is filled with air and feeding starts. These early fry (or swim-up fry) can then be transported to the nursery ponds.
Water requirement of the hatchery is about 15–20 1/sec, the greater part of this is consumed in the ward tanks, the water of which has to be changed frequently (once an hour). Water supply of the hatchery must be totally safe and good in quality. Therefore, a settling buffering reservoir must be constructed and the water must be filtered by a fine-gravel or sand-filter. Although the main canal will grant gravity supply to the hatchery (thus pumping can be avoided), the head of the water in the dry season is just marginal. Therefore, the connecting pipeline between the settling tank and the hatchery must be thick, some 3 inches in diameter.
The piping within the hatchery must also be overdimensioned for the same reason (2-inch diameter is necessary). For the water supply to the ward tanks, locally available threaded taps would be sufficient and safe; but for the hatching and larval-rearing devices, finely adjustable ball valves are recommended.
The building of the hatchery has only one purpose - to provide protection against the strong sunshine. A simple wooden structure with split bamboo walls and thatched roof would suffice. However, taking into account the wet conditions within the hatchery, the foundation has to be made of masonry, elevated well above the floor of the hatchery.
2.3 Design of the Auxiliary Facilities
2.3.1 Field Laboratory, Office
A building of traditional design constructed of local materials, supplied with drinking water, electricity and telephone. It comprises the following main compartments:
| - | field laboratory | - 20 m2 |
| - | office for technical staff | - 20 m2 |
| - | office for administrative personnel | - 18 m2 |
| - | store-room for chemicals and other supplies | - 24 m2 |
| - | bathroom, lavatory, corridor | - 18 m2 |
| - | built-in area | - 100 m2 |
| - | built-in volume | - 300 m3 |
| - | built-in power | - 15 kW |
2.3.2 Garage, Workshop
A building of wooden frame, with strong wire-mesh or split bamboo walls, thatched roof for storing the project vehicle, making smaller repairs and fabricating home-made equipment for the hatchery:
| - | built-in area | - 35 m2 |
| - | built-in volume | - 90 m3 |
| - | built-in power | - 5 kW |
2.3.3 Residences
As fish seed production is delicate work requiring continuous (day and night) control, at least two technical staff members (one senior and one junior) must live at the farm centre. According to local standards, the housing requirement is 100 m2 and 75 m2 respectively. The residences have to be of traditional design, constructed from locally available materials, but must be supplied with drinking water and electric power:
| Senior residence: | built-in area | 100 m2 |
| built-in volume | 300 m3 | |
| built-in power | 10 kW | |
| Junior residence: | built-in area | 75 m2 |
| built-in volume | 225 m3 | |
| built-in power | 8 kW |
2.3.4 Wardens' Hut
As the fish stock kept at the farm is of high genetic value, protection against poachers is essential. At the far sides of the farm two elevated wardens' huts have to be constructed of local materials (wooden frame, split bamboo walls, thatched roof) to shelter the wardens and give them a good view over the pond area.
Total built-in area of two huts - 10 m2.
2.3.5 Access Road
Within the first phase of development, a blacktopped access road is not planned. However, it is important to construct two culverts across the main irrigation canal, as well as the canal along the western border of the area. The access road, however, has to be improved by gravel and stone-chip filling all along its 600-m stretch (from the paved road of the town to the farm centre). In the second phase of the development, blacktopping of the access road is inevitable.
2.3.6 Drinking Water
The laboratory, offices and residences have to be supplied with drinking water, even in the first phase of development. This requires a 600-m long pipeline from the town to the farm centre and an additional 100-m piping within the farm centre. The main line must have a 1-inch diameter, internal lines can be constructed with 3/4-inch diameter.
2.3.7 Power Supply
Although the built-in power capacity of the farm centre is close to 50 kW, simultaneous energy consumption at any given time will remain below 25 kW even after completing the second phase of development. Therefore, a 600-m primary line, a pole transformer of 40–50 kVA capacity and some 150-m secondary line must be constructed.
2.3.8 Telephone
Smooth operation of the fingerling distribution, as well as accessibility of the extension services, requires connexion to the national telephone network. As only the office must be supplied with a telephone, a line of 600-m length and one plug with three sockets will be required.
2.3.9 Fencing
Minimum requirement of fencing is to protect the farm centre plus the broodstock ponds against intruders. It is advisable, however, to construct a fence all around the farm. This should be a barbed-wire fencing on wooden posts.
2.3.10 Sewers
For the residences and the office sewage collecting, desiccating pits must be constructed. These must be dug to a depth where the rough gravel layer is met in order to ensure proper desiccation.
3. INVESTMENT COSTS
Investment costs were calculated on the basis of local data collected at the Public Works Department (Sarbhang and Thimbu), Agriculture Department, Power Department and the Telcom (Thimbu).
Investment costs of the first phase of the centre's construction are estimated as follows:
A. Land acquisition
| 8.4 ha | B.N. 25 000/ha | B.N. 210 000 |
B. Construction of ponds, structures and canals
Earthwork, by hand, within 30 cm depth, up to 45 m delivery distance:
| 5 440 m3 | B.N. 2.53/m3 | B.N. 13 763 |
As (i), but more than 30 cm depth (normal soil):
| 5 440 m3 | B.N. 3.33/m3 | B.N. 18 115 |
Irrigation canals, masonry, with thick cement plaster (included soil excavation):
| 50 × 50 cm | |||
| 468 m | B.N. 75.44/m | B.N. 35 306 |
As (iii), but 60 × 60 cm
| 131 m | B.N. 91.84/m | B.N. 12 031 |
Masonry structures with thick cement mortar, thick cement plaster, dressed stones
| 43 m3 | B.N. 194.50/m3 | B.N. 8 321 |
Linings, thin concrete on gravel fill
| 300 m2 | B.N. 32.52/m2 | B.N. 10 656 |
RCC span tubes, imported, Ø 38 cm, with collar, 6 ft long,
| 45 pieces | B.N. 132.00/piece | B.N. 5 940 |
As (vii), but Ø 61 cm
| 27 pieces | B.N. 198.00/piece | B.N. 5 346 |
| Component total | B.N. 109 478 | |
| B.N. 110 000 | ||
C. Hatchery
Building of wooden frame, split bamboo walls, thatched roof
| 100 m2 | B.N. 450.00/m2 | B.N. 45 000 |
Masonry tanks with thick cement mortar, thick cement plaster, dressed stones
| 66 m3 | B.N. 194.50/m3 | B.N. 12 837 |
Linings, thin concrete on gravel fill
| 86 m3 | B.N. 35.52/m3 | B.N. 3 055 |
| Component total | B.N. 60 892 | |
| B.N. 61 000 | ||
D. Buildings
Residences (two), traditional design, local materials, supplied with power and drinking water
| 100 + 75 = 175 m2 | B.N. 900/m2 | B.N. 157 500 |
Laboratory-office, traditional design, local materials, supplied with power, drinking water and telephone
| 100 m2 | B.N. 900/m2 | B.N. 90 000 |
Garage-workshop, wooden frame, split bamboo walls, thatched roof, supplied with power
| 35 m2 | B.N. 450/m2 | B.N. 15 750 |
Elevated wardens' huts (two), wooden frame, split bamboo walls, thatched roof
| 2 × 5 = 10 m2 | B.N. 450/m2 | B.N. 4 500 |
Demonstration pig stall, erected above the pond surface, wooden frame, slotted hardwood floor, split bamboo walls, thatched roof
| 20 m2 | B.N. 450/m2 | B.N. 9 000 |
| Component total | B.N. 276 750 | |
| B.N. 277 000 | ||
E. Services
Road improvement with stone chip fill
| 500 m3 | B.N. 30.00/m3 | B.N. 15 000 | |
| - Culvert from Ø 61 cm RCC span tubes | B.N. 800 | ||
| - As above, but from twin Ø 91 cm RCC span tubes | B.N. 5 000 | ||
Drinking water supply, Ø 1-inch zinc coated pipe (with installation)
| 700 m | B.N. 40.00/m | B.N. 28 000 |
Power supply, primary transmission line with transformer
| 600 m | B.N. 25.00/m | B.N. 15 000 |
- As above, but secondary line with outdoor fittings
| 150 m | B.N. 20.00/m | B.N. 3 000 |
Telephone, connecting line to city network
| 600 m | B.N. 15 000/m | B.N. 9 000 |
| - Indoor fittings and installation | B.N. 500 | |
Fencing, barbed wire on local wooden posts
| 1 100 m | B.N. 12.00/m | B.N. 13 200 |
Sewer collecting and desiccating pits
| 3 pieces | B.N. 500.00/pieces | B.N. 1 500 |
| Component total | B.N. 91 000 |
Total estimated costs of investments are as follows:
| A. | Land acquisition | B.N. 210 000 |
| B. | Pond and canal construction | B.N. 110 000 |
| C. | Hatchery | B.N. 61 000 |
| D. | Buildings | B.N. 277 000 |
| E. | Services | B.N. 91 000 |
| Grand total (Phase 1) | B.N. 749 000 | |
While for the first phase of investments detailed calculations were made, total investment costs of the second phase were only guessed, as the future price increases cannot be properly estimated. Rough estimates of the investment costs of the second phase of construction (at the present prices) are as follows:
| A. | Pond and canal construction | B.N.108 000 |
| B. | Hatchery | - |
| C. | Buildings | B.N.284 000 |
| D. | Services | B.N.166 000 |
| Grand total (Phase 2) | B.N.649 000 | |
This sum includes the costs of acquisition of additional 3.7 ha of land, construction of additional 2.52 ha of net pond surface, erection of an additional three residences, blacktopping of the access road, expansion of the drinking water supply, power transmission lines and fencing the new area.
4. IMPLEMENTATION OF THE PROJECT
The project definitely requires international assistance as follows:
local experts are not available for the supervision and control of pond and hatchery construction and for fish pond and hatchery management;
existing technical staff of warmwater fisheries has no experience in broodstock-raising, selection, induced breeding, larval-rearing and nursing techniques;
foreign currency is not available.
As Bhutan does not have a qualified field aquaculture engineer, it is recommended that the construction should be carried out under the supervision and guidance of an international expert, but with the active participation of a local counterpart (an engineer, having practical experience in construction of irrigation schemes). The local counterpart will thus receive in-service training in aquaculture engineering and will be able to supervise construction of the second phase of the centre, as well as future development programme without further international guidance.
Construction should start with the broodstock ponds, their water supply and drainage, as well as with the hatchery. After having completed one or two ponds, importation of breeder candidates should start (Chinese carp and Indian major carp broodstock should be imported from Nepal or India, common carp broodstock preferably from Hungary). They should be transported by air, using plastic bags filled partially with water and partially with oxygen.
When the construction of the hatchery and its water supply is completed and sexually mature breeders are obtained, involvement of an international aquaculture expert with experience in induced breeding becomes inevitable. Under his guidance, the hatchery facilities will be put into operation, all the equipment required will be procured and/or prepared locally, and the technical staff will receive thorough in-service training in induced breeding techniques.
One of the important tasks of the aquaculture expert should be the orientation of those local farmers who are interested in introduction of improved market fish production techniques (polyculture, integrated fish farming, etc.). In order to facilitate demonstrations and practical training for the local farmers, one of the nursery ponds should be used for demonstrating market fish production integrated with pig production. After the completion of the second phase, the fingerling ponds will be used for this purpose, as well as for demonstrating fish-cum-duck production techniques.
It is highly recommended that during the construction period 2–3 fishery inspectors and/or fishery assistants be sent to Nepal and/or India for 3–6 months of production-oriented practical training. With this type of training, these staff members could easily be upgraded to medium level technicians, who after completing their training by working closely together with the aquaculturist (consultant) of the project may become the leaders of the planned fry distributing and extension subcentres.
The most capable fishery inspector should be selected for 9-months' training, at the Fish Culture Research Institute (Szarvas, Hungary). Here, the trainee will receive production-oriented training in broodstock selection, induced breeding, hatchery and nursery management, and integrated fish farming. After completing this term, the trainee may become the national counterpart of the aquaculturist and, later, the Head of the Warmwater Fish Seed Production Centre.
It should be clearly understood that all these activities require time. A realistic estimate would be a time-period of three years. Stationing international personnel continuously in Gaylegphug for a three-year period would not be required. Terms of the aquaculture engineer and the aquaculture consultant could be planned with some overlapping only, and the aquaculturist should assume his duties in two six-month terms, covering two propagation seasons.
5. OUTPUTS TO BE ACHIEVED
Establishment of a genetically valuable broodstock of known origin in itself might grant 20–25 percent higher productivity, compared with commercial stocks, and 25–35 percent higher productivity compared with fry collected from natural waters. Thus, the establishment of the Warmwater Fish Seed Production Centre's broodstock and the exclusive use of its progeny for market fish production in the private sector might increase the country's fish production by 25–30 percent without any further increase of pond surface area.
The broodstock raising facility of the centre (four broodstock ponds with a total net area of 1.0 ha) will hold some 1.2–1.5 t of fish, of which only 50 percent will serve for induced breeding and for “stand-by” reserve. Another 50 percent will be breeder candidates of various ages, subject to strict selection procedures year by year. Thus, the broodstock ponds will yield as a product annually some 0.7–0.8 t of big-sized market fish (above 2 kg each).
Production capacity of the nursery ponds (1.52 ha total net surface area) will be about 114 000 fingerlings in a 6-month season. The rest of the year might be utilized for market fish production, which may result as an average of 1.4 t/ha, thus producing a total of 2.1 t of small-sized market fish (0.5 kg each) per year. Until the above number of fingerlings are required by the private sector, one or two nursery ponds could be used for market fish production all the year round.
Estimated value of production at the end of the first phase of development:
| - | 114 000 fingerlings of 5 cm size at 10 fingerlings/B.N. 1, | B.N. | 11 400 |
| - | 2 128 kg small market fish, B.N. 20/kg, | 42 560 | |
| - | 750 kg large market fish, B.N. 20/kg, | 15 000 | |
| Total | B.N. | 68 960 |
After completing the construction of the fingerling ponds (scheduled in the second phase of development), as an addition to the above figure, the following production can be expected:
| - | 80 560 fingerlings, 10 fingerlings/B.N. 1 | B.N. | 8 560 |
| - | 3 528 kg small market fish, B.N. 20/kg | 70 560 | |
| B.N. | 79 120 |
When fully operational, the total value of fish and fingerlings produced by the centre is estimated to be B.N. 148 080/year.
