The area under culture at Bundala Salt Works can be expanded. Instead of utilizing only the initial 9.8 ha pond, it should be possible to utilize two additional ponds of 20 and 27.1 ha for aquaculture. This would raise the total area under aquaculture to 56.9 ha. The depth of pond water at 60 to 90 cm is deep enough for the culture of penaeid shrimp. In fact, local fishermen used to come and catch both shrimp and fish from the initial concentration pond until the company prevented entry of the fishermen to the pond.
A number of modifications will be required in order to expand and improve culture operations:
a screen box, at least 2 × 4 m and having a mesh size not larger than 3 mm should be installed to filter the water where the intake pipes enter the water canal;
the ponds should be separated from each other by new water gates with adequate screening and water control boards;
internal canals at least 50 cm deeper than the pond bottom should be dug in the second and third evaporation ponds to provide shelter for the fish and shrimp.
The screens would reduce the number of predaceous fish which enter the pond and prevent fish and shrimp from moving between ponds. Milkfish would be stocked in all ponds at a low stocking density, say 500 per ha.
A further improvement would be to divide the second and third ponds into smaller units. With the good supply of pumped water flowing through them these units could be utilized for culturing penaeid shrimp with feeding. An appropriate start would be to construct two shrimp culture units in one evaporation pond (see Figure 3). The larger portion of the pond would still be used to grow fish, but the fish should grow better since the water is being enriched in the shrimp culture tanks.
Once convinced of the favourable economics, management of the salterns might decide to operate the aquaculture units throughout the year instead of closing down during the rainy season. As there are a number of salt works throughout the country where similar programmes exist, production could be significant. In addition, it is possible that a modified water management programme would allow more ponds to be brought into aquaculture production, using the same amount of water.
SKETCH LAYOUT OF SUGGESTED MODIFICATIONS FOR BUNDALA - SALT WORKS
