AQUACULTURE (FISH FARMING)

FISH POND CONSTRUCTION AND REPAIR


Draining and drying. Drain and dry the pond completely. Dry for about a week or more, depending upon the weather, until the bottom cracks or harden sufficiently to support a man on his feet without sinking more than 1 cm.


Make sure the pond soil is dried every time the pond is harvested. Periodic drying stabilize soil colloids and oxidizes organic matters that encourage the growth of natural fish foods. Draining and drying eradicate competitor fishes and predators, and kill disease-causing organisms.


Cultivation of pond bottom.

Till or cultivate the pond bottom as soon as it is drained. Do this by stirring or cultivating with a shovel or a rake for small ponds. For large ponds, use a rotavator. Cultivation makes sub-surface nutrients available at the surface for the growth of fish food in the pond, eradicate burrowing predators like mudfish and eliminate undesirable pond weeds like "aragan."


Levelling.

Level the pond bottom after this is cultivated. Levelling makes the pond bottom slope gradually from its farthest end down towards the drainage structures - the deepest portion of the pond.




Repairing gates and screens.

Check all gates and pipes for broken slabs and other parts. Repair screens to prevent predators and pests from entering the pond system. Clean to remove debris which may cause clogging.


Repairing dikes.

Check all dikes for leakages and seepages. All dikes must be water-tight. Put a puddle trench excavated about 30 cm wide and 50 cm deep or more along the dike. Build this at the center of dike towards one side, or dig two puddle trenches at both sides of pubbled trench long enough to cover the entire seepage and sufficiently deep to go beyond the general level of the pond floor. Fill the trench with new mud or soil. Allow the soil to settle well to give a firm line of earth