Production of Pompano

The silver pompano, Trachinotus blochii and Indian pompano, Trachinotus mookalee are the candidate species for aquaculture due to its good meat quality and high market demand. They are less cannibalistic and resistant to a wide range of diseases and easily mature under captive condition. Juvenile inhabits sandy coastal waters and estuaries in small schools, while adults are usually solitary. It is a voracious carnivore which feeds on even hard-shelled invertebrates including molluscs. Large adults are mostly golden orange, especially on the ventral side. The dorsal snout is very steep but rounded.

Seed Production

Broodstock management

The collection of sub-adult and quarantine protocol is the same as that explained for cobia. After quarantine, the fish weighing not less than 1.5 kg is stocked in a tank (10 t capacity) having re-circulation facility. The fish is fed with squid, cuttlefish, crab, shrimp and chopped oil sardine along with pelleted feed and fish sausage.

Water quality management

It is practiced in a similar way to that explained for the milkfish.

Spawning

After anaesthetising the fish, cannular biopsy is done periodically to assess ovarian maturation. The female having ova with a minimum size of 500 pm diameter is selected for breeding. Female to male ratio is maintained at 1:2. They are induced to breed by the injection with HCG at 350-500 IU/kg body weight for both the sexes. Spawning occurs in circular tank within 36 hours after hormone injection. Fertilisation is external and the fertilised egg has one prominent oil globule and is buoyant, transparent and yellowish with a size of 0.9-1 mm diameter. It is collected from the water surface for incubation. The unfertilised eggs which settle at the bottom are removed by siphoning. Fecundity is 0.6-1.8 lakh/kg body weight, and the fertilisation rate is 75-90%. The domesticated pompano spawns naturally in accordance with lunar cycle.

Incubation

The fertilised eggs are collected and incubated in a similar way as explained for the cobia. The eggs hatch-out between 18-22 hours. The hatchling is observed under a microscope for pigmentation and appearance of internal organs and deformation or abnormalities, if any. The mouth of the hatchling appears in 3 dph with an opening of 230 micrometer.

Live feed production

The method practiced is the same as that explained for the milkfish.

Indoor rearing

The stocking rate, size of indoor rearing tank and maintenance of phytoplankton is same as that explained for cobia. Larval feeding can be started from 3 dph with enriched Brachionus plicatilis at a density of 8- 10 no./ml for 2-3 times daily until 14 dph. Mixed feeding with rotifer and enriched Artemia nauplii is carried-out during 11-14 dph. The Artemia nauplii are provided at a density of 2-5 no./ml upto 19 dph.

Indoor rearing

Weaning on artificial larval feed starts from 15 dph onwards and mixed feeding with Artemia is continued till 19 dph. From 20 dph onwards, the feeding is entirely on artificial diets. The metamorphosis of the pompano larva starts on 18 dph and metamorphoses into juveniles within 25 dph. Though cannibalism is not much prevailed, grading should be done during 20-25 dph for separating shooters. No water exchange is normally required till 7 dph and later on it is done at 10% from 8 dph which is gradually increased to 100% from 25 dph.

Rearing of fry

After 25 dph, the larvae are graded by size and the different size groups are reared in separate tanks. The fingerling attains 5-7 cm size within 55 dph. The tank capacity, stocking density, feeding and water quality management are similar to that explained for cobia.

Packing and transportation

The method followed is similar to that of cobia.

Farming in Cage

Site selection

Eventhough it is a marine fish, it can be cultured in brackish waters with a salinity of not less than 10 ppt. The site should also be free from turbidity. Other aspects of site selection are similar to that of cobia.

Water quality requirements

• Temperature : 27- 30°C
• pH : 7.5- 8.2
• Salinity : 10-35ppt
• DO : >5 ppm
• TAN : 0.5 ppm
• Turbidity : <10 NTU

Construction of cage

In the case of sea cage farming, the design should be same as that specified for cobia and for brackish water cage farming, it should be done as specified for pearlspot.

Stocking

After acclimatisation, the hatchery-produced seeds of 5-7 cm (2-3 g) size are stocked at a density of 40 no./m³. The mesh size required for the cage net is given below.

Mesh size of cage net

Feeding

Pompano is a fast moving fish and it requires nutritious feed to meet the energy requirement. The growth rate and the details of feeding ration are given in below Table. Other aspects are the same as that of cobia.

Feed requirement

Care and maintenance

Procedures for these are similar to that explained for cobia. The growth rate of pompano is given in Table below.

Growth rate

Harvesting

Selective harvesting of large fish is done from 6th month onwards. In the domestic market, pompano fetches good market demand from 300 g size onwards. The fish usually attains 600 g within 9 months. A production of 16 kg/m³ can be expected from one crop. Survival rate in cage farming is 80-85%. Other aspects of harvesting are similar to that of cobia.

Source : Department of Fisheries, Government of Kerala