1. CULTURE OF ASIAN SEABASS

2. The Asian sea bass Lates calcarifer - important coastal, estuarine and freshwater fish in the tropical and subtropical Indo-Pacific region
It is widely distributed from the Gulf of Arabia to Northern Australia.
Highly Euryhaline with a complex life history
Protandrous hermaphrodite and catadromus fish
Spawning occurs in brackish waters of 28 to 36 ppt salinity, near river mouths

3. Spawns from January to August, spawning is triggered by a rise in temperature.
spawns usually around full moon and new moon days coinciding with spring tides
Highly predacious and cannibalistic, which is the main difficulty in culture of this fish
Stringent size grading is required in the culture environments
The fish is fast growing and commands good price in local and international markets, hence this is one of the species cultured in Australia, Hong Kong, Singapore, Malaysia and Thailand.

4. Source of seed
Fry - produced in hatcheries
Fish - matured in sea cages and bred through environmental manipulation of hormonal injections
Wild ripe spawners can also be collected and stripped followed by dry method of fertilization
Eggs hatch in hours at a temperature of 29-31°C

5. They are hatched in seawater of salinity 30 ppt
Larvae start feeding from the 2nd day onwards when they are fed marine rotifer Brachionus plicatilis
From day 8 post hatch they are fed with Artemia nauplii or cladocerans
25-30 days post hatch they are fed with ground trash fish meat/sub-adult and adult Artemia
Grading is essential to prevent cannibalism starting from 2nd weed post hatch.

6. Grow-out culture
In recent years- floating cages
Problems –cannibalism and feeding
Grow-out - performed in two phases
First phase- fry are grown to a weight of about 20 g in special nursery type of ponds of upto 2000m²
Stocking rate /m².
Besides natural food produced by fertilization, the fry are fed with supplementary feed consisting of ground trash fish twice a day
Exchange of 30% per day
Reared for 30 – 40 days
fingerlings of similar size sorted out and stocked in separate grow out facilities for growing to market size.

7. Grow-out period - for 3-4 months in Philippines, where g fish are acceptable and 8-2 months in other countries where marketable sized fish is 700g to 1.2 Kg
Floating and stationary cages of different sizes (usually 50m²) are used
Stocking density in cages is fish /m³, after 3 months stock is thinned out to 10-20/m³
Feed chopped trash fish or pelleted feed specially formulated for Asian sea bass
They are 10% of the biomass twice daily for two months after which it is reduced to 5% once a day.

8. In poly culture fish are reared with forage fish such as tilapias in the ratio of 1:20
The ponds are first stocked with the forage fish which reproduce rapidly and produce fry and fingerlings as food for the sea bass
When sufficient food is produced sea bass juveniles are stocked at a rate of 3000 to5000 per ha
In monoculture system sea bass juveniles are stocked at 10,000 to per ha with artificial feeding
Intensive culture of sea bass has proved to be economical and a production of about tonnes can be obtained
The stocked fish in ponds grows to 500g in 6 months; 800 g in one year and to 3 Kg in one and half to two years