Rural Industries Research & Development Corporation

The New Rural Industries
A handbook for Farmers and Investors

Barramundi

Introduction

Barramundi (Lates calcarifer) farming in Australia started in the mid-1980s in north Queensland. The industry has grown rapidly, and although the bulk of the production still comes from north Queensland, the fish is now farmed in all mainland States except Victoria. Barramundi is also farmed in many countries in South-east Asia, where it is known as sea bass.

Barramundi has many attributes which makes it an excellent species for aquaculture. Broodstock can be spawned easily (all year round under controlled conditions) and they produce many offspring. Fingerling production is reasonably straightforward.

They can be raised intensively indoors, or in extensive outdoor ponds. The species is easily weaned onto pelleted diets and grows very quickly. It is a hardy fish and adapts well to crowding.

It can be grown in fresh and salt water, so it can be farmed on the coast or inland. Barramundi also adapts well to indoor, environmentally controlled recirculating water systems. It is a sought-after table fish and commands a premium price in the market. About 460 t of farmed barramundi was produced in Australia in 1995-96, valued at about $5m. The knowledge base and facilities of the current producers could support a two- to four-fold increase in production.

Barramundi farmers have come from all walks of life, although most are from a farming background. The successful ones share several personal attributes, such as the ability to learn new skills associated with fish husbandry and marketing, a commitment to building a new business in the face of early difficulties and unprofitable periods, a willingness to take financial risks, and adequate capital to support the initial establishment phase.

Marketing issues

Most farmed barramundi (ca 70%) is marketed as plate-size product, ie. 350-500 g. The remainder is sold as large (> 2 kg) fish. Prices at the point-of-first-sale in 1995-97 generally ranged from $9.50-11.50/kg. Most product is sold by direct consignment to wholesalers in Sydney and Melbourne, although smaller producers tend to trade via the auction floor. There is also a small trade in live fish, generally supplied by the producers in southern Australia.

A premium is paid for the Australian product, even though Australian wholesalers can import fresh, chilled barramundi from south-east Asia, often at prices below the cost of production in Australia. Although the exact quantity is not known, the amount imported is probably more than that farmed in Australia.

The key constraint to future expansion is the ability of the industry to develop the domestic market and identify profitable overseas markets. Increasing the production of plate-sized barramundi to more than
500 t/year, without extensive promotion, will result in a fall in the price paid by Australian wholesalers. The Australian Barramundi Farmers Association (ABFA) is currently conducting a marketing campaign so that the anticipated production increase will meet a 4ñì

In the longer term the industry is looking at product diversification and market opportunities overseas. It is envisaged that the diversification will include fillets from larger fish (up to 3 kg), for which there is a large domestic market, and the production of barramundi cutlets for sale in supermarket chains. In addition, product diversification will pave the way for export development.

Production requirements

There are three quite different methods currently used for growing fingerlings to market size. The most common grow-out system is cage culture in purpose-built freshwater ponds. Another method is cage culture in estuarine waters, although relatively few companies are doing this at the present time. The third system is intensive production indoors, in controlled-environment buildings, using underground (ie. pathogen-free) water and a high level of recirculation through biological filters.

Barramundi require warm (tropical) temperatures to sustain commercial growth rates. For this reason, farming in ponds and estuaries should be undertaken only in areas where the water temperature in winter remains above 20^°C. In coastal regions this means areas north of Townsville (see map). Barramundi can live at temperatures as low as 16^°C, but growth virtually ceases and the immune system is depressed, making the fish very susceptible to disease.

The controlled-environment systems can be operated anywhere in the country. The capital and operating costs for these facilities are usually greater than for the equivalent level of production in outdoor cage operations. However, they can be located close to markets, thus defraying costs associated with transporting product to market.

Other factors to consider when assessing the suitability of a site for barramundi farming include:

• an abundant supply of high-quality water;

• for pond systems, impermeable soils on a gently sloping terrain;

• proximity to essential services and infrastructure such as a work force, technical and veterinary expertise, support industries (feed manufacturers, hardware, mechanical, electricity) and processing facilities;

• ability to secure the site against poachers and predators;

• future adjacent developments that may have environmental impacts affecting fish health;

• proximity to local and domestic markets; and

• proximity to a major airport.

As with other forms of aquaculture, a range of government permits is required for farming barramundi.

Varieties

There has been no selective breeding of barramundi. To implement such a program would be difficult because of the logistics associated with maintaining adequate numbers of family lines through generations.

Fish husbandry

There are three distinct phases to barramundi aquaculture: the hatchery phase, involving broodstock maintenance and larval rearing; nursery rearing; and grow-out. Salt water is essential for broodstock maturation and larval rearing, while the nursery and grow-out phases can be conducted in either salt or fresh water.

The hatchery component of barramundi farming is very specialised, as it requires dedicated and expensive facilities, access to salt water, preferably saltwater ponds for larval rearing, and a considerable degree of technical skill.

Broodstock can be kept in spawning condition year-round if housed in environmentally controlled tanks, with temperature and photoperiod emulating the natural spawning season. Spawning requires the injection of reproductive hormones.

Fertilised eggs are collected from the spawning tanks and transferred to incubators. Hatching takes about 14-17 hours, and larvae commence feeding
1-2 days after hatching. Larval rearing is conducted intensively in hatcheries, or extensively in fertilised saltwater ponds. Larvae change to juvenile fish at
11-12 mm total length, which corresponds to about
12-20 days after hatching, depending on food supply and water temperature during the larval phase.

Some hatcheries do not maintain broodstock, but buy fertilised eggs from other hatcheries, which are then reared to fingerlings. The majority of farmers, however, neither maintain broodstock nor operate hatcheries, preferring to source their stock as fingerlings from the few large farms with hatcheries. Fingerlings are generally sold at between 25 and 45 mm total length. Larger fingerlings are more expensive but easier to rear.

Fingerlings are maintained in nursery facilities until approximately 80 mm total length. Nursery facilities are small fibreglass tanks or fine-mesh cages (about 1 m³) floating in larger tanks. Weaning of fingerlings from natural live food organisms to manufactured diets is conducted in the nursery. Cannibalism can be a major cause of mortality during the nursery phase. To prevent this, the fish are size graded regularly.

Fish are transferred to grow-out cages when they are over about 80 mm total length. Cages are made from knotless mesh netting, and vary in size from
4-50 m² surface area and 2-4 m deep. Biofouling can reduce the size of the mesh openings and thus restrict the flow of water through the cages, leading to poor water quality. Consequently, the mesh must be changed and cleaned regularly.

Stocking densities of between 15 and 40 kg/m³ are most common, but higher densities are used on some farms. Barramundi are fed on commercially available pelleted diets. Fish are fed up to 6 times/day when first weaned. The frequency of feeding is reduced progressively to once per day when the fish weigh more than about 100 g. Semi-floating pellets, rather than sinking pellets, are now widely used because they are available to the fish for a longer time and feeding activity is more easily observed.

Water quality parameters such as dissolved oxygen, pH, temperature and light penetration need to be monitored frequently. Aerators are used to maintain dissolved oxygen levels at greater than 5 ppm. Water exchange rates vary depending on the intensity of production, but generally about 5-10% of the pond water is exchanged daily.

Provided good husbandry is practised, and fingerlings are supplied at the beginning of the growing season (late Oct-early Nov), marketable, plate-size fish will be attained in 6-8 months. Growing fish to 2-3 kg may take 2-2.5 years.

Disease control

Like all other cultured animals, barramundi is subject to a range of bacterial, fungal, viral and parasitic diseases. Disease outbreaks are usually associated with some form of stress, such as, for instance, extremes of temperature, low dissolved oxygen, poor nutrition or handling of the fish. Stress can be reduced by ensuring water quality remains near optimal levels, by reducing densities (to a practical yet economic level), and by feeding high quality diets. Watching for signals such as appetite depression, irregular swimming patterns, increased frequency of gill movement and any general irregularities facilitates rapid diagnosis, enabling early treatment and reduced mortality.

Bacterial infection is by far the most common cause of disease in barramundi aquaculture. Columnaris disease is particularly common in small fingerlings held in water below about 25^°C. Other bacterial diseases are seen throughout the year but generally become more prevalent in mid-winter and mid-summer. Another factor that is often associated with bacterial disease is frequent grading. Once fingerlings are moved from nursery tanks to grow-out cages and grading frequency declines, disease incidence also declines. Bacteria have numerous points of infection, but damaged skins in badly affected fish seem to be common.

Fungal infections are most prevalent in cold waters (less than about 22^°C), and are equally common in fish reared in fresh and salt water. Fungal infections appear as white blotches on the skin, and usually follow skin damage resulting from handling.

Two viral diseases have been reported in barramundi in Australia. Both are of relatively minor significance in terms of affecting production, and are easily prevented by maintaining hygienic conditions in hatcheries and grow-out environments.

Small numbers of parasites are often found in farmed barramundi. Disease outbreaks are relatively uncommon, but when they do occur rapid diagnosis and treatment are necessary to avoid large losses. The most commonly encountered parasitic disease is white spot in broodstock held in salt water. White spot is caused by the protozoan Cryptocaryon irritans, and is controlled by bathing the fish in fresh water for several days.

The major pest problem in fresh water is water rats. These are controlled by trapping and relocating. Predatory birds, such as cormorants, are not a serious problem in barramundi farming in fresh waters, because fish are usually held in cages or tanks which the birds cannot access. On marine farms, considerable losses can occur as a result of predators (eg., sharks, crocodiles, dolphins, puffer fish) making holes in nets, thus allowing fish to escape. To exclude such predators, marine farms have heavy-meshed predator nets suspended around the perimeter of the farm.

Harvesting, processing and packaging

As most farmed barramundi are produced in cages, harvesting is relatively simple. It is only a matter of gathering up a corner of the net to concentrate the fish, and scooping them out with nets. Handling nets should be made of a soft knotless mesh, to reduce any physical damage associated with extracting fish from the cages.

After harvesting from the cages, the fish are euthanased by immersion in an ice slurry. They are then graded according to size and packed in plastic bags in styrofoam boxes for transport. The great majority of fish are now sold guts-in; processing takes place at the wholesale or retail points in the marketing chain. Farms have processing and packaging facilities either on site or close by. Department of Health approval is required for processing facilities.

The product is generally transported by air to the large seafood markets in Sydney, Melbourne and other capital cities. Strict packaging regulations are imposed by the airlines. Road transport is used for local markets, and for transport of live fish.

Economics of production

The likely profitability of barramundi farming is calculated using a model farm which is based upon current industry practices in northern Queensland (A detailed report on the economics of barramundi aquaculture is available from the Queensland Department of Primary Industries). The model farm is 15 ha in area and produces an annual turnoff of 50,000 kg of whole, plate-size barramundi.

To establish an early cash flow, it is assumed that 12—month-old fish are produced to provide returns in the first year. Production parameters and capital costs for the farm are given in Tables 1 and 2, respectively. The yearly income and operating costs are given in Table 3.

Table 1. Production parameters for model barramundi farm.

Table 2. Capital cost of establishing the model barramundi farm. (tables to come)

Table 3. Yearly cash income and cash operating costs.

Table 4. Summary of profitability criteria at different prices.

Discounted cash flow analysis is used as the economic evaluation method. This method evaluates a project over its estimated life, assumed to be 20 years, by discounting future cash flows to present values by the opportunity cost of funds employed (8% in this case). Three profitability criteria are shown here:

• Annualised profit—the net present value, the difference between the present value of cash inflows and the present value of cash outflows, expressed on an annual basis (note in this case the annualised profit is net after capital and labour);

• Internal rate of return—the rate of interest at which the net present value is zero. If funds can be borrowed at less than the IRR, the project will pay for itself;

• Payback period—the minimum number of years to recover project costs.

Prices for whole barramundi have fallen over the past few years. The analysis presented in Table 4 illustrates the impact of various price scenarios on profitability criteria. Payback period increases and annualised profit decreases as prices decline. Assuming production remains constant, the breakeven price, the price at which the annualised profit is zero, is $9.33/kg of whole barramundi.

The model barramundi farm analysed above is likely to be profitable, but there are other possible impacts to consider. Loss of production through disease, water quality problems, unforseen environmental conditions and lack of knowledge can severely affect the profitability of the enterprise. Another factor is the lack of markets, mentioned previously. Markets should be sought out and researched before venturing into barramundi production.

Key contacts

Key references

Barramundi Farming Information Package. Available through the Freshwater Fisheries and Aquaculture Centre, Walkamin. The package is regularly upgraded to include recent developments.

Rimmer, M. 1995. Barramundi Farming - An Introduction. QDPI Information Series No. QI95020, 26 pp.

Rimmer, M. and Rutledge, W. 1991. Extensive rearing of barramundi larvae. QDPI Information Series No.QI91012, 6 pp.

Palmer, P., Burke, J., Willett, D. and Simpson, R. 1992. Development of a low-maintenance technique for rearing barramundi larvae. QDPI Information Series No.QI92036, 19 pp.

Austasia Aquaculture is a bimonthly magazine which covers aquaculture in general, and often contains specific information on barramundi farming. A Trade Directory is also produced annually. Subscriptions can be made by contacting Austasia Aquaculture, PO Box 658, Rosny, Tasmania 7018 (phone: 03 - 6245 0064).

Acknowledgments

The author thanks the following people who have contributed to this article: Bill Johnston provided the economic analyses; Ian Anderson, Ian Ruscoe and Les Rodgers assisted in assembling information; Joanne De Faveri prepared the Sydney fish auction data; and Mike Rimmer, Cris Phillips and Dennis Hart commented on a draft of the manuscript.

*About the author