When mass production of Clarias larvae is initiated at the Landjia hatchery, the technique described can be applied, incubating great numbers of eggs in Zug-Weiss type jars. The larvae collecting technique also can be applied here.
When the larvae production starts on a commercial scale, larger females (1–2 kg) can be used for egg production purposes.
The simplest and cheapest larvae-rearing technique is in nursery ponds on pond-produced natural food. When mass production of the Clarias fingerlings starts special nursery ponds should be constructed for this purpose. The description of the nursery ponds and their conditions has already been given.
The duck-raising system on the farm should be changed. The young ducklings should be adapted to life on the water as early as possible. A shallow ditch (a few square metres in surface) can be constructed near to the present keeping place where the few-days-old ducklings can swim during the daytime. They dry in the sun soon after swimming. The bottom of the shallow ditch can be made from PVC sheet to avoid the seepage of the water. The ditch has to be drained and cleaned each day; continuous water supply of the ditch would be preferable.
Adaptation to life on the water should start on the third day but in case of cold or bad weather at the latest on the fifth day of life. At night the ducklings should be closed in for their safety. Light, food and drinking water should be provided also at night. The water-accustomed ducklings can be put on the ponds at least from 10–14 days of life.
The ponds of Landjia farm are rather poor from the production point of view. Organic manure is essential for maintaining the productivity of the ponds. It is advisable to extend duck-keeping on the farm. This implies a bigger brood duck stock and 3–4 incubators.
To control the water weeds and utilize the grass which grows on the farm area, the introduction and rearing of grass carp is advisable. But only the bigger size of grass carp (0.3–0.5 kg and more) is effective in grass control. The hatchery, with adequate apparatus, can carry out propagation activities also of carp. (More and bigger jars and concrete tanks are needed for propagation purposes.)
As the grass is plentiful grass-feeding experiments can be started. In the pond, the grass carp would be the main fish and Tilapia and others secondary species.
Because of the presence of small phytoplankton and rotifers in well manured ponds, silver carp (Hypophthalmichthis molitrix) could also be introduced. The silver carp would not disturb the Tilapia-raising activity.
In Bouar farm the artificial propagation of common carp should be repeated in October or November when the reproductors are ready for propagation.
