Aquaculture research and development

The research arm of the DAC is currently working on a four year, Australian Centre for International Agricultural Research (ACIAR) funded project entitled, 'Sea ranching and pond culture of sandfish (Holothuria scabra) in Asia-Pacific - Trial of sea ranching of sandfish in an Australian Indigenous community'. This project is undertaken in collaboration with the Warruwi Community on Goulburn Island and The WorldFish Center partners in Vietnam and the Philippines.

The DAC also manages research programs to develop giant clam and tropical oyster farming methods suitable for remote Indigenous communities. This includes developing hatchery techniques to produce oysters and clams and addressing constraints facing grow out of these species in remote NT regions.

The centre produces fingerlings for restocking Manton Dam and some of the approved lakes around Palmerston, and a golden snapper breeding program has commenced in 2016 for stock enhancement of Darwin Harbour.

The DAC has often taken a collaborative approach to aquaculture research and development, partnering with Queensland, Western Australia, New South Wales, South Australia and overseas organisations so that a critical mass of researchers and technicians can be gathered to address particular projects. The research and development at the DAC has been generously supported over the years by the Fisheries Research and Development Corporation, Australian Centre for International Agricultural Research, and Ausindustry. We have also been fortunate to benefit from collaboration and support from a range of other organisations including:

• Skrettings
• Marine Harvest
• Clean Seas
• McRobert Aquaculture Systems
• Southeast Asian Fisheries Development Centre (SEAFDEC)
• Australian Research Council
• Western Australian Fisheries (WA Fisheries)
• Queensland Department of Agriculture and Fisheries
• Cooperative Research Centre for Aquaculture (CRC for Aquaculture)
• Tasmanian Seafoods
• Paspaley Pearling Company
• Arafura Aquatic Fish

All commercial aquaculture activities require the operator to have an appropriately endorsed aquaculture licence. Grant of the licence will require prior approval from various agencies and includes the requirement for an environmental management plan.

Sea cucumbers

The Darwin Aquaculture Centre became a member of the Australian Seafood CRC in 2010 and began a three year research program in collaboration with its commercial partner to improve the hatchery and nursery production of sea cucumbers.

Sponges

In response to growing interest in sponge aquaculture a Sponge Aquaculture Development Group was formed in 2003. This group was instrumental in raising funds for a two year programme to examine the feasibility of sponge farming in the Northern Territory.

A range of Aboriginal communities and organisations supported sponge farming development and trial grow-out of sponges in 2004. Late in 2003 researchers from the Australian Institute of Marine Sciences sponge resources along the Arnhem Land coast. This survey provided information on suitable species to trial near the various participating communities. Training was undertaken to assist Aboriginal peoples take part in the sponge grow-out trials. An economic assessment of sponge aquaculture was completed at the end of the trials to determine the economic viability of sponge farming under NT conditions.

Unfortunately, no sponge culture enterprises operate in the NT today. This is largely due to the type of species that occur in the NT, problems with developing suitable technology for the high energy environments and the reliance on divers to maintain growout structures. However, this work led to the development of a viable Indigenous led industry in the Torres Strait assisted by the Australian Institute of Marine Sciences and James Cook University.

Reef fish aquaculture

As the aquaculture industry develops around the world there is increasing interest in investigating the potential of new species for aquaculture.

Many fish farmers are looking to diversify production to mitigate risk and develop a competitive edge for their businesses. Of particular interest are tropical marine finfish or reef fish. This term covers a wide range of fish, but most recent work has been on the snapper and grouper families.

Fish such as barramundi cod (Cromileptes altivelis), coral trout (Plectropomus species) and tropical snappers (Lutjanus species) have recently been the subject of research projects in Australia, Southeast Asia, the South Pacific and Latin America. These fish have wide market acceptance for their excellent eating characteristics and generally command high market prices.

In 1993 the Darwin Aquaculture Centre (DAC) began on a research program to develop aquaculture techniques for the golden snapper, Lutjanus johnii. By 1997 DAC’s finfish research team had developed a new technique for snapper culture based on a locally available copepod (a small crustacean found in the zooplankton of the world’s oceans). Using this technique golden snapper were reliably produced in commercial numbers.

Although a commercial partner has still to be found to continue developing golden snapper farming, these culture techniques are suitable for a wide range of fish species, including difficult-to-rear tropical marine aquarium fish, grouper species and even mahi mahi (dolphin fish).

For the moment, reef fish research at the DAC has been scaled back to concentrate on the commercial production of barramundi in support of the NT's barramundi aquaculture industry.

Prawn aquaculture

In Australia, prawn farming generally refers to the farming of marine or brackish water species (often termed shrimp in other countries) as opposed to fresh water 'prawns' such as cherabin.

In Australia, prawn farming generally refers to the farming of marine or brackish water species (often termed shrimp in other countries) as opposed to fresh water 'prawns' such as cherabin. In the NT, the main species farmed is Penaeus monodon, more commonly known as the black tiger prawn. Prawn farming is carried out in earthen ponds filled with sea water and aerated to supply oxygen and maintain the good water quality needed for optimal growth. The prawns are manually fed with specially formulated, pelleted feeds.

The juvenile prawns used to stock the ponds are sourced from purpose-built hatcheries. These hatcheries provide the conditions necessary for the mature broodstock to produce the eggs that will grow to be juvenile prawns. The process of producing eggs and rearing them through to juvenile prawns is a demanding one and is carried out by skilled technicians.

Prawn farming is a capital intensive activity with high overheads and prawn farmers require an appropriate level of aquaculture knowledge and relevant business skills.

The prawn farming industry in the NT commenced in1983 and expanded steadily till 2006. Production for the NT was near 100 tonnes in 2006 with a value of $1.6M. Production declining significantly afterwards due to the impact of cheaper imported prawn products. Consequently prawn farmers gradually changed to barramundi production between late 2006 and mid 2008

Prawn aquaculture useful links

• ABARE
• Australian Prawn Farmers Association
• Queensland - Department of Agriculture and Fisheries
• Western Australian - Department of Fisheries
• New South Wales Department of Fisheries
• SEA-EX - Aquaculture information and links
• Seafarms Group

Redclaw crayfish aquaculture

Redclaw (Cherax quadricarinatus) is a type of freshwater crayfish native to the westerly and northerly flowing rivers of Queensland's Gulf of Carpentaria, the easterly and northerly flowing rivers of the Northern Territory and the southerly flowing rivers of Papua New Guinea.

Redclaw is very similar to the marron (C. tenuimanus Smith), and the yabby (C. destructor sp.). All three have attracted significant commercial interest both within Australia and internationally. Freshwater crayfish production in Australia averaged 272 mt per year (92.4 mt per year for redclaw) for a five year period (2003/04 to 2007/08) with an average value of $17,586 per mt ($13,796 per mt for redclaw).

Since the early 1980s there has been widespread interest in redclaw crayfish aquaculture in Australia. Industry pioneers were quick to learn of the species’ positive farming attributes, such as fast growth rates, ease of reproduction, lack of free-living larval stages, gregariousness, and the ability to tolerate low water quality. Redclaw are cultured in specifically constructed, semi-intensive aquaculture ponds. Average yields are around 1,600 kg/ha. The best farms are producing in excess of 3,000 kg/ha, and up to 5,000 kg/ha. Redclaw can be harvested at any size and can therefore fulfill almost any market order.

Appropriate land and water resources are probably restricted to the northern part of the Territory except for localised pockets in the central regions.

If you would like more information on redclaw crayfish aquaculture contact the Darwin Aquaculture Centre (08) 8924 4260.

Mud crab aquaculture

The mud crab (Scylla serrata) is a highly regarded and valued table food item in both Australia and Asia. Mud crab aquaculture is not currently undertaken in the NT but it has been carried out in a number of Asian countries for many years. Mud crab farming in these areas is generally based on catching juveniles from the wild and using them to stock into mangrove enclosures, pens or ponds for grow out. Aquaculture can supply crabs to a range of markets. As well as the markets for the regular hard shelled crabs there are also niche markets for females with mature ovaries, and soft-shelled crabs.

Mud crab useful links

• ABARE
• SEA-EX - Aquaculture information and links
• FAO - Fisheries Information Centre
• SEAFDEC - Southeast Asian Fisheries Development Center
• Queensland - Department of Agriculture and Fisheries

Cherabin aquaculture

Cherabin are freshwater prawns whose natural distribution stretches from India through to Papua New Guinea, Northern Australia and North to Indonesia and the Philippines.

The native cherabin Macrobrachium spinipes is a large species endemic to the northern rivers of Queensland, the Northern Territory and Western Australia. The global annual aquaculture production of cherabin exceeds 130,000 metric tons, and comes chiefly from Asia. There is currently no production of cherabin in Australia.

There have been several attempts to farm cherabin in Australia since as early as the mid-1970s. Since then, many improvements to production technology have occurred, such as the use of hides or refuges, and feeding regime. Yields have generally risen from about 1000 kg/ha/crop to in excess of 3000 kg/ha/crop. A crop takes about 150-170 days, but depends on preferred market size and rearing temperatures.

Cherabin produce pelagic or free-swimming larvae that prefer brackish water, so a hatchery with access to good quality salt water is necessary for larval rearing.

If you would like more information on cherabin aquaculture please contact the Darwin Aquaculture Centre (08) 8924 4260.

Microalgal aquaculture

Spirulina is the only commercially grown microalgae in the NT. Spirulina is a microscopic, spiral shaped blue-green fresh water alga that grows naturally in warm, highly alkaline lakes in subtropical areas around the world.

It has been harvested, dried and used as a nutritional supplement in many cultures for centuries. It contains all the amino acids, is high in protein, a good source of beta-carotene, vitamin B12, iron, other trace elements and minerals and essential fatty acids.

In 1998 TAAU Australia Pty Ltd constructed a pilot project at Berry Springs to assess the feasibility of growing Spirulina. Based on the technical success of the experimental twelve-pond farm, the operation expanded to ninety-six ponds.

Spirulina is grown in lined ponds 50m x 20m x 300mm deep. Water is circulated through each pond to maintain optimal growing conditions for the algae. To harvest, pond water is pumped through filter mats that remove most of the algae from the water. The resulting green paste on the mats is removed and spray dried to form a powder. The powder is sold to wholesale markets or pressed into tablets for both the retail and wholesale markets.