1. Management scheme
Recent developments in West Africa indicate that intensive mono-culture of Tilapia nilotica, using males only, in certain settings may be commercially viable. Such a culture is analysed in this annex. Calculations will be made for three different farm sizes: 1, 5 and 15 hectares.
The farm has three types of ponds, all about 0.2 ha in size. Fry is harvested continuously from brood ponds and raised for two months in rearing ponds before being subject to manual sexing. The females are sold and the males stocked in production ponds for growth to market size.
2. Inputs
Excavation accounts for the major part of pond construction costs (assuming that land is suitable, i.e., not covered by trees or dense brush). Therefore the costs of pond construction do not decrease markedly with the increase in size of the farm (assuming, as we have done, that the size of individual ponds remains about the same). See Table 12.1.
However, for a commercial farm of 5–15 ha size, staff quarters, offices, stores and vehicles, must also be provided and the investment quickly becomes substantial when compared to the value of yearly production. Because of the considerable investment, depreciation and interest occupy between 30 and 40 percent of annual cost for a farm under full operation. Amongst the recurrent costs, feed and salaries account for the greater part.
3. Output
The production of 7 t of tilapia per ha (of production pond) and year, using a feed consisting of 75 percent rice bran and 25 percent cotton seed cake, has been proven feasible elsewhere. In our calculations seed cake has been replaced by wheat bran and fish meal (5 percent). As part of the pond area is used for brood stocks and for grow-out of fingerlings, the effective yield is about 5.95 t/ha of pond area and year.
4. Returns
The revenue generated, under different assumptions of prices at the farm gate, is shown at the bottom of Table 12.2. Comparing gross revenue and costs it is amply evident that this type of corporate fish culture, for the local market, is not now commercially possible in Sri Lanka.
The price of Cey.Rs. 12/kg at the farm-gate, may be considered the equivalent of an export price. Even at that price the farm is a doubtful proposition. It hardly reaches commercially viability. Even were the price of feed halved, or the conversion factor halved (from 4 to 2), the effects on the commercial viability are not as drastic, as for example, in cage culture, as in this example of pond culture feed only accounts for some 30 percent of total costs (in our analysis of cage culture, cost of feed accounts for 60 percent).
The above analysis is carried out under two very favourable assumptions: (a) that the cost of land is zero (i.e., no lease is paid or other agricultural production foregone), and (b) that water can be obtained through gravity flow. In fact, in most Sri Lankan inland fish culture stations, pumping is necessary during most of the year.
Table 12.1 Pond construction and associated investments for tilapia farms
| Items | Units | Cey.Rs./unit | Farm Size | |||||
| 1 ha (5 ponds) | 5 ha (2 ponds) | 15 ha (60 ponds) | ||||||
| No.of units | Cey.Rs./unit | No.of units | Cey.Rs./unit | No.of units | Cey.Rs./unit | |||
| Land clearing | ha | 3 600 | 1 | 3 600 | 5 | 18 000 | 15 | 54 000 |
| Excavation and building bunds | m3 | 39.00 | 4 500 | 175 000 | 21 000 | 819 000 | 60 000 | 2 340 000 |
| Monks/sluice gates | ea | 9 500 | 5 | 47 500 | 50 | 190 000 | 60 | 570 000 |
| Turfing and watering bunds | m2 | 7.75 | 3 400 | 26 350 | 15 000 | 116 250 | 42 000 | 325 500 |
| Water canals, inlets | 115 000 | 200 000 | 550 000 | |||||
| Miscellaneous | % | 10 | 36 050 | 10 | 134 750 | 10 | 383 500 | |
| Sub-total | - | - | - | 404 000 | - | 1 478 000 | - | 4 223 000 |
| Buildings: | ||||||||
| store, office, watchman's hut | m2 | 1 500 | 50 | 75 000 | 60 | 90 000 | 100 | 150 000 |
| house for foreman | m2 | 1 500 | 80 | 120 000 | 80 | 120 000 | ||
| house for manager | m2 | 1 500 | 120 | 180 000 | ||||
| Sub-total | - | - | - | 75 000 | - | 210 000 | - | 450 000 |
| Vehicles: | ||||||||
| jeep | ea | 70 000 | 1 | 70 000 | 1 | 70 000 | ||
| pick-up | ea | 100 000 | 1 | 100 000 | 1 | 100 000 | ||
| manager's car | ea | 100 000 | 1 | 100 000 | ||||
| Sub-total | - | - | - | - | - | 170 000 | - | 270 000 |
| Total | 479 000 | 1 858 000 | 4 943 000 | |||||
Table 12.2 Yearly revenues and cost of operation for tilapia farms
| Items | Units | Cey.Rs./unit | Farm Size | |||||
| 1 ha (5 ponds) | 5 ha (20 ponds) | 15 ha (60 ponds) | ||||||
| No.of units | Cey.Rs. | No.of units | Cey.Rs. | No.of units | Cey.Rs. | |||
| Personnel: | ||||||||
| - unskilled labour | man-year | 6 000 | 4 | 24 000 | 15 | 90 000 | 40 | 240 000 |
| - watchmen | " | 6 000 | 1 | 6 000 | 1 | 6 000 | 2 | 12 000 |
| - drivers | " | 9 000 | 1 | 9 000 | 2 | 18 000 | ||
| - foremen | " | 12 000 | 1 | 12 000 | 1 | 12 000 | 1 | 12 000 |
| - manager | " | 24 000 | 1 | 24 000 | ||||
| Sub-total | 42 000 | 117 000 | 306 000 | |||||
| Feed1 | kg | .845 | 23 800 | 20 100 | 119 000 | 101 000 | 357 000 | 302 000 |
| Fertilizer | ton | 1 000 | 1 | 1 000 | 5 | 5 000 | 15 | 15 000 |
| Transport | 20 000 | 30 000 | ||||||
| Maintenance | % | 8 000 | 27 000 | 76 000 | ||||
| Sub-total | 29 100 | 153 000 | 423 000 | |||||
| Depreciation | 12 000 | 100 000 | 225 000 | |||||
| Interest2 | % | 10 | 26 000 | 10 | 103 000 | 10 | 273 000 | |
| Total cost | 109 100 | 473 000 | 1 227 000 | |||||
| Gross sales proceeds: | kg | 4 | 5 950 | 23 800 | 29 750 | 119 000 | 89 250 | 357 000 |
| kg | 6 | 5 950 | 35 700 | 29 750 | 178 500 | 89 250 | 535 500 | |
| kg | 12 | 5 950 | 71 400 | 29 750 | 357 000 | 89 250 | 1 071 000 | |
