BARRAMUNDI

This information comes from DPI Queensland handout

Barramundi, (Lates calcarifer). Occurs naturally throughout the northern areas of Australia. In Queensland they predominantly occur in the central and north parts but some fish are caught as far south as the Noosa River. Genetic differences have been detected between fish from the different river systems. Barramundi(Lates calcarifer) are known as Sea Bass in southeast Asia.

Culture Environment

Barramundi(Lates calcarifer) are a tropical species requiring water temperatures between 20° C and 30° C. Commercial growth rates require temperatures above 25° C. Being euryhaline (able to tolerate a wide range of salinities), barramundi can be grown in sea, brackish or freshwater. This allows them to be cultivated in ponds, sea cages and recirculating systems. Ponds and sea cages need to be located in areas that will provide the longest growing seasons.
Barramundi(Lates calcarifer) production in freshwater ponds is usually carried out in cages suspended from a walkway, anchored across the pond. Cages vary in size from 2m x 2m to 5m x 10 m and are 1.5 to 2 metres deep. Pond sizes range from 0.5 to 1 hectare and are 2 to 3 metres deep.
Growout in sea cages occurs in floating cages with the same dimensions as in freshwater operations. Large round (Polar Circle) cages provide additional production potential.
Intensive heated indoor recirculating systems are established in the southern areas of Queensland. Most farmers utilise a series of 5 or 10 tonne production tanks connected to a solids removal device and a biological filter. The systems may be located close to markets and other infrastructure because of their ability to control environmental parameters.

Breeding and fingerling production

Barramundi(Lates calcarifer), in the wild, spend their juvenile years in fresh or brackish water before migrating as adults to estuaries to spawn. Spawning occurs during full and new moons over the summer season. Hatcheries are now able to spawn barramundi in captivity year round with controlled lighting and temperature. Juveniles mature first at 3 to 4 years as males and change at 6 to 8 years of age to females. Females are capable of multiple spawnings and generally produce 3 to 6 million eggs per season. The sexually mature broodstock can be induced to spawn by injecting with a synthetic luteinizing hormone releasing analogue (LHRHa). Fish spawn 24 to 36 hours after the injection. The eggs and larvae require saltwater for successful fertilisation and survival. Larvae are either raised using tanks or more extensive rearing ponds. Linking an intensive green-water tank phase (2 weeks) with a subsequent pond phase provides the best results with high survivals (90%) and low size variation.
The larvae metamorphose at 8-10 mm long and are then called fry. Weaning the fry onto artificial feeds starts at about 18 mm. Once the fry are over 20 mm they are normally called fingerlings. Cannibalism in fingerlings can cause massive losses unless they are graded every 10-14 days. Grading normally starts at 30-50 mm or earlier if there is a large size variation in the batch and continues until the fingerlings are lOO mm long.

Growout

Commercial growout in ponds or recirculating systems is started once the fingerlings reach 30-80 mm. Fingerlings are stocked at up to l5 kg per m3 of water. The fingerlings are fed a semi-floating pellet 5 to 6 times per day when they are small. This decreases to once or twice daily as they grow. Pellet size increases as the fish size increases. Pellets are fed until feeding ceases. The quantity of feed utilised by the fish decreases rapidly with a decrease in water temperature. Maximum intakes occur at 27° C to 29° C and decreases to almost zero at 20° C. Feed conversion ratios (total weight of fish produced per total dry weight of feed consumed) of 1.5: 1 to 2: 1 can be expected in well managed operations at optimum temperatures.
Seasonal variations in temperature cause growth rates of pond reared fish to decrease rapidly' over the winter months, even in north Queensland. In southern Queensland, the lower year round water temperatures makes this method uneconomical even if they survive the winter. Death is reported to occur when water temperatures drop below 13° C, although stress related mortalities and disease outbreaks become increasingly frequent as the water temperature drops below 200 C. Ponds are normally aerated with aspirators, which circulate the water through the suspended cages. Water exchanges are carried out to remove ammonia and control algal blooms. Production from these ponds can reach 20 tonnes per hectare.
Intensive heated recirculating systems require a higher level of management than the pond systems because of the incorporation of a biofilter system, which removes toxic products (ammonia and nitrites), by a process, called nitrification. There are many different designs of recirculating systems, which can be used. Some are more suitable than others for barramundi.

Marketing

The majority of the product has been marketed to restaurants in the gilled and gutted form weighing 350-475 g. Some fish will reach this size in 6 months over the summer period. More recently some of the farms are holding the fish over the second summer and getting fish to 2-3 kg, which are suitable for the fillet market.

References

"Barramundi (Lates calcarifer) farming information package", (1996), DPI, Freshwater Fisheries and Aquaculture Centre, Walkamin.
Rimmer, M., (1995), "Barramundi farming an introduction", DPI, Northern Fisheries Centre, Cairns.
Johnston, W. et al. ( 1999). "Barramundi Farming CD" Barramundi profitability and technical information. Cost $200. DPI -Bribie Island Aquaculture Research Station and Freshwater Fisheries and Aquaculture Centre, Walkamin.
The State of Queensland. Department of Primary Industries 1999 Bribie Island Aquaculture Research Centre, PO Box 2066, Bribie Island Q 4057. 14 December 1999 Information contained in this publication is provided as general advice only. For application to specific circumstances, professional advice should be sought. The Department of Primary Industries, Queensland, has taken all reasonable steps to ensure the information in this publication is accurate at the time of publication. Readers should ensure that they make appropriate enquires to determine whether new information is available on the particular subject matter.