Pond Culture
The majority of freshwater fish are raised in ponds. Water taken from a lake, river, well or other natural source is channelled into the pond.
Fish farming ponds range in size from a few dozen square metres to several hectares (ha). Small ponds are normally used for spawning and baby fish production, while larger ponds are used for the grow-out period. Production ponds larger than 10 ha become difficult to manage and are not very popular with most producers. The ponds illustrated here serve only as examples. The kind of pond a farmer will build depends very much on local resources, equipment and conditions.
It is important that sufficient water is available to fill all the ponds within a reasonable period of time and to maintain the same pond water level. You should also be able to drain the pond completely when the fish are to be harvested. Side slopes should be 2:1 or 3:1 (each metre of height needs 2 or 3 metres of horizontal distance), which allows easy access to the pond and reduces the risk of erosion problems.
Characteristics of a good pond for fish farming
Location- Select land with a gentle slope, taking advantage of existing land contours.
Construction- Ponds may be dug into the ground; they may be partly above or below original ground level. Slopes and bottom should be well packed during construction to prevent erosion and seepage. Soil should contain a minimum of 25% clay. Rocks, grass, branches and other undesirable objects should be eliminated from the dikes.
Pond depth- Depth should be 0.5-1.0 m at shallow end, sloping to 1.5-2.0 m at the drain end.
Configuration- Best shape for ponds is rectangular or square.
Side slopes - Construct ponds with 2:1 or 3:1 slopes on all sides.
Drain- Gate valves, baffle boards or tilt-over standpipes should be provided. Draining should take no more than 3 days.
Inflow lines- Inflow lines should be of sufficient capacity to fill each pond within 3 days. If surface water is used, the incoming water should be filtered to remove undesirable plants or animals.
Total water volume- Sufficient water should be available to fill all ponds on the farm within a few weeks and to keep them full throughout the growing season.
Dikes- Dikes should be sufficiently wide enough to allow mowing. Dike roads should be made of gravel. Grass should be planted on all dikes.
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