MANILA, Philippines – It is always rewarding to talk to people who have the know-how and who are willing to share their expertise.

Dr. Aida Palma of the Tanay Research Station of the Bureau of Fisheries and Aquatic Resources is one fish scientist who can be very helpful.

She was a guest a few Sundays ago at the radio program which we co-host (Kaunlaran sa Agrikultura, aired every Sunday, 4:30 to 7:30 in the morning). There she shared the latest results of their experiments in tilapia production. She said that the optimum stocking rate in tilapia is 10 pieces per cubic meter of water, whether it is in the fishpond or in cages in the lake. They experimented on stocking 5, 10, 15 pieces per cubic meter. The best result was obtained from stocking of 10 pieces. More than that, the fish are too crowded and will not grow as fast.

Another practical technique is what she calls skip feeding. This means that the tilapia should be fed every other day instead of every day. This will not only economize on feeds, it will also result in less pollution of the water which could result in fish kill. Recommended rate of feeding is 3 percent of body weight.

There is also what she calls the stocking of “advance” fingerlings. This means stocking the pond or cage with bigger fingerlings. Instead of stocking the pond with fingerlings that are less than one inch, she recommends stocking two-inch fingerlings or bigger. This will result in less mortality and there will be a shorter culture period in the pond. One other advantage is that since there is a shorter growing period to attain marketable size, the fish are exposed to possible typhoons and floods for a shorter period.

She also has some practical suggestions on cage culture of tilapia. The size of the cage will depend on the financial capacity of the fish farmer. If he can’t afford a very big cage, he can use 10 meters by 10 meters with the depth of the cage depending on the depth of the lake and the quality of the water.

She cited the cases of Lake Buhi and Lake Bato in Camarines Sur. The water in Lake Buhi is deep and is less polluted than Lake Bato. So the net can be as deep as five meters. Which means that more fish could be cultured per cage because there is a bigger volume of water.

In the case of Lake Bato, the water is just 2 to 3 meters deep. In this case, the suggested depth of the fish cage is one meter. Dr. Palma also said that the bottom of the netcage should be at least one meter higher than the bottom of the lake.

Avoid feeding tilapia too early in the morning because there is less dissolved oxygen at this time. Wait for 8 to 9 o’clock before feeding.