Barramundi aquaculture

Market and industry

Most barramundi is marketed to domestic wholesalers and supermarket chains as whole fish or fillets, but export markets are growing.

The main market is for larger fish (2–3kg), with plate-sized fish (400–800g) also taking a significant portion of sales. Queensland's climate permits pond-based production of plate-sized barramundi in the first year of farming. To reach weights of 2–3kg, barramundi require a second grow-out season.

Despite an increase in formulated feed costs, production costs are decreasing. As with other aquaculture industries, economies of scale are important to reduce production costs.

Download the annual aquaculture industry report for the latest barramundi valuation and production data. You can also contact the Australian Barramundi Farmers Association (ABFA) for advice and support.

Culture environment and production systems

Barramundi can tolerate a wide range of salinity and can be grown in seawater, brackish waters or freshwater. This means you can cultivate barramundi in ponds, sea cages and recirculating systems.

In Queensland, most barramundi farms use ponds. Both ponds and sea cages need to be located in areas with warmer water that will allow for the longest growing seasons.

Water temperature

Barramundi requires water temperatures from 20–30°C. To achieve commercial growth rates, the ideal temperature is 25–30°C. The growth rates of outdoor fish are slow during the winter months, even in North Queensland.

Variations in water temperature can seriously affect barramundi:

• below 20°C, there is an increase in the frequency of stress-related deaths and disease outbreaks
• below 13°C, deaths will occur.

To ensure viable growth, farms in southern Queensland use heated, re-circulating, indoor production systems, rather than ponds, due to lower year-round temperatures.

Freshwater ponds

Barramundi production in freshwater ponds involves the use of floating cages for the first part of the grow out period. Cages are accessed from walkways and individual cages vary in size from 2m x 2m, to 6m x 12m, and are 1.5–2m deep.

Most farmers choose to release barramundi from the cages once they reach a size that makes them less vulnerable to predators (usually heavier than 300g). The fish are then grown free–range in a pond to a weight of 2–3kg.

Annual production from ponds can reach 30t per hectare, but is more often 10–15t per hectare.

Sea cages

Barramundi grow out takes place in floating sea cages, which are generally larger and more robust than the cages used in freshwater operations.

Recirculating aquaculture systems

In southern Queensland, intensive heated indoor recirculating aquaculture systems (RAS) are used. Most RAS farmers use a series of 5–10t production tanks connected to a solids removal device and a biological filter.

There are many different recirculating system designs, some are more suitable than others for barramundi. Ensure you thoroughly research and seek expert advice on which design is best for your farm site

Breeding

Hatcheries are now able to spawn barramundi in captivity year-round with controlled lighting and temperature. Juveniles mature first at 3–4 years as males and change at 6–8 years to females; however, under aquaculture conditions maturation occurs in about half that time.

Egg production

Female barramundi are capable of multiple spawnings and generally produce 3–6 million eggs per season. Sexually mature broodstock can be induced to spawn using a hormone injection.

Fish spawn 24–36 hours after the injection. The eggs and larvae need salt water to be successfully fertilised and survive. Larvae can be raised using tanks but are more often grown in extensive rearing ponds.

Chemicals used in aquaculture, including hormones, require veterinary advice and prescriptions before use.

Fingerling production

Larvae metamorphose at 8–10mm and are then called fry. At about 18mm, you can wean the fry onto artificial feeds. Once the fry are over 20mm (at 2–3 weeks of age), they are called fingerlings.

Cannibalism in fingerlings can cause massive losses unless they are regularly graded (sorted by size) every 7–10 days (for smaller fingerlings). Grading normally starts at 30–50mm, or earlier if there is a large size variation in the batch. Grading continues until the fingerlings are at least 100mm long.

Feeding and growing

Commercial grow out in ponds or recirculating systems starts once the fingerlings reach 30–100mm in size. Fingerlings are stocked at up to 15kg per cubic metre of water.

Feeding

Small fingerlings are fed a semi-floating pellet 5–6 times a day. This decreases to 1–2 times a day as they grow. Pellet size increases as the fish size increases. You should feed pellets until all feeding stops.

A decrease in water temperature lowers the amount of feed required by a fish, barramundi:

• achieve maximum food intake at 27–29°C
• decrease their intake to almost zero at 20°C.

If operations are kept at optimum temperatures (25–30°C), you can expect feed conversion ratios (total weight of fish produced per total dry weight of feed consumed) of 1.2:1 to 1.8:1.