Rural Industries Research & Development Corporation

The New Rural Industries
A handbook for Farmers and Investors

Abalone

Introduction

Abalone are slow-growing herbivorous marine snails. There are over 100 species worldwide in the same genus, Haliotis, of which less than 10% are commercially important.

They are found from the intertidal to the depth limit of marine plants (approximately 80-100 m), from tropical to cold waters. Aquaculture of abalone began in Australia about 16 years ago in Port Lincoln, South Australia and in Tasmania, through research into spawning blacklip and greenlip abalone.

In contrast, abalone aquaculture is over 50 years old in Japan. The impetus for developing abalone aquaculture in Asian countries, and later in the USA, Mexico and South Africa has been the decline in their wild harvest fisheries because of over-exploitation.

Australia has been fortunate that fisheries management has controlled the level of commercial abalone harvest at sustainable levels. Even so, Australia's abalone catch has declined from 8000 t in 1971-/72 to 5200 t in 1995-96.

Abalone are high price species that are grown intensively in both sea and land-based systems. Importantly, the trend in abalone culture has matched that worldwide for other aquaculture species in that successful culture in highly developed countries is dependent on total control over the grow-out conditions. The vagaries of climatic extremes that are experienced in the marine environment result in variable commercial viability with higher risk. The trend is to develop land-based systems that permit total control over growing systems. Seawater may be derived from shore-based pumping, artesian aquifers or by combining raw marine salt with inland freshwater sources. Aquifers have an added advantage in that temperature is often elevated and constant, but volumes may be low, and inland disposal of spent water is a problem.

Increases in world abalone prices in the last 15 years have made abalone aquaculture in Australia a more viable proposition. Australia supplies over 40% of the world's wild-harvested abalone, and its two main commercial species (blacklip and greenlip) have significant price margins over abalone species harvested from the tropics, subtropics, New Zealand, Chile and Europe. In 1994-95 prices for Australian abalone reached record levels of $38-45/kg (whole weight). Since then market price has steadied at
$35-40/kg.

South Australia and Tasmania have led Australia's abalone aquaculture development in the past 10 years. There are currently 9 farms in South Australia and 12 in Tasmania, with development expenditures to date being $5.5m and $7.5m, respectively. Both Victoria and Western Australia are in the early stages of introducing abalone aquaculture, with three new state-of-the-art shore-based facilities being developed in Victoria.

In the past 20 years, China and Taiwan have developed abalone aquaculture industries with annual production estimated at 500 and 1500 t, respectively. However, during this period both countries have continued to be net importers of abalone products, as their internal demand for product cannot be met by domestic production. China is reaching the limits of sites suitable for development. Further, typhoons frequently cause extensive damage to sites in China. Taiwan has continued to experience water quality problems that have plagued its prawn industry, and this is expected to restrict future development.

Most of the first business plans for abalone aquaculture in Australia used a figure of
4-5 years to reach a market size of 70-80 mm. The rapid industry acceptance of manufactured diets and improved tank technology over the last three years has seen this figure reduced to 3-4 years. This makes investment far less risky and provides for a faster return on investment. The development of hatcheries producing millions of juveniles has allowed new operators to establish grow-out operations without the need to develop a hatchery, further reducing the time for positive cash flow.

Abalone farming is much like intensive rearing of livestock, in particular pigs and poultry. The skills required involve a mixture of biology, engineering and innovation. Abalone farmers in Australia have come from professional, farming and fisheries backgrounds. Key staff, in particular those working in the hatchery phase of production, are usually aquaculture graduates.

Markets and marketing issues

It is important to differentiate the market for cultured abalone and the wild product. Wild product from Australia has limited markets as it is restricted by the minimum harvest size limits imposed on capture (120-145 mm). It is sold by weight. The aquacultured product, on the other hand, can be sold at any size.

The world market for aquacultured abalone is primarily for live individuals in the size range 50-100 mm. The aquacul-tured product fetches a premium over wild product. The small quantities of cultured product that have been marketed domestically have usually fetched prices in the range $40-45/kg (live, whole weight) for 70-80 mm Australian product. With a decline in wild-harvested abalone stocks and growing demand in Asia, prices will con-tinue to rise for the next 20 years.

Almost all of Australia's abalone product is sold to Asian markets, with only a small amount being sold on the domestic market. For live product the farmer usually sells direct to a distributor in Hong Kong, Singapore or Japan. Canned or fresh-frozen product is sold to local abalone processors who then sell to wholesalers in Asia when the price and shipment volumes are right. Successful abalone farming will require good market knowledge. At present abalone farmers are using Australia's wild fishery market links. Value adding will be achieved in future with the development of specific aquaculture markets and labelling promoting the quality of the product.

Production requirements

Abalone require water of the same chemical composition as seawater.

Siting of farms is one of the most important development decisions. The most important factors for siting land-based abalone farms are:

• access to marine quality water that has low daily and annual temperature variations, and averages the optimum temperature requirement for the species;

• freedom from pollution, in particular urban development run-off;

• low cost land;

• low head height for pumping water from either ocean or aquifer;

• access to environmentally approved methods for waste seawater disposal; and

• close to infrastructure and services, including three-phase power, airfreight terminal and trades people.

Existing land-based abalone farms are located on the coast in rural regions. In South Australia the main constraint has been finding sites close to three-phase power supply which have access to clean water supplies. Similarly, in other States access to sites is limited by coastal parks, electricity supplies, and isolation from services and infrastructure. The development of recirculated temperature-controlled systems (using less water) could see small abalone farms utilising inland aquifer saline water that has the added benefits of relatively constant temperature and of being pathogen free. However, coastal sites will be the preferred land-based sites.

Species

Abalone are marine snails belonging to the class Gastropoda of the phylum Mollusca. These are molluscs with single shells, or no shell at all, and which move by means of a broad muscular foot. Currently only two species of abalone are being farmed in Australia: greenlip (Haliotis laevigata) and blacklip (H. rubra). Greenlip is farmed in SA, Victoria and Tasmania, and blacklip in Victoria and Tasmania. Greenlip is preferred for culture because it has a faster growth rate (20-30 mm/year) than blacklip (15-25 mm/year) and a higher market price.

In Western Australia, Roes abalone shows promise, and its intertidal habitat means that it is tolerant of a broad range of culture conditions. The tropical abalone, H. asinina, has created interest because preliminary growth trials have shown it to be one of the fastest growing abalone (>40 mm/year) in the world. New ventures are proposed in Broome and Cairns using this species.

Farmers in SA, Victoria and Tasmania are interested in developing the hybrid between greenlip and blacklip abalone. There is evidence that this hybrid grows more rapidly and is easier to handle than its parents in certain grow-out designs. The `tiger' colour variation of blacklip found in Victoria has potential as this form is similar in colour to the premium-priced Japanese species. Crossing the cold-water species H. rubra with H. cyclobates, is yielding individuals that may have a broader temperature tolerance.

Fish husbandry

Farm types. There are two types of land-based abalone farms: hatchery based and grow-out only. The former method is vertically integrated, comprising three stages of production:

1. hatchery;

2. nursery; and

3. grow-out.

Hatchery-based farms are more technically difficult to operate, require greater capital costs and are riskier, as the production cycle is considerably longer. Conversely, the rate of return on hatchery-based farms is higher. In Australia, hatchery-based farms are more akin to industrial aquaculture that employ a large number of staff (>30) and plan to produce large quantities of product (> 200 t).

Grow-out only farms buy juvenile abalone (20-25 mm, 1 year old) from hatcheries and aim to grow abalone to production size in less than 2.5 years. The grow-out farm requires tank structures of only one type and the farmer's principal jobs are system maintenance, cleaning, feeding, stock grading and harvest. This farming method is more suitable for a family operated business with one or two staff.

Typical grow-out farm layout. A typical land-based grow-out farm starts with the seawater intake system. This must be capable of pumping upwards of 5-100 ML/day. An ideal site has a low head for pumping and low suspended solids in the water, reducing the need to filter or backwash. Most farms have a primary filter before the pumps, then sand filters after the pumps capable of filtering down to
10-20 microns nominal.

The best site has a low inclination away from the water source, which facilitates gravity drainage and the capability to cascade water from tank to tank. Water is delivered by a manifold to tanks set up in parallel. Water is collected at the end of tanks in a common sump that allows wastewater to be processed before returning to the sea or being recharged into the aquifer. Tanks are shallow, permitting use of low pressure/high volume air blowers. The delivery line for the air is usually a 100-300 mm PVC pipe. Reliability is crucial, so it is important that backups of all mechanical equipment exist and that spares are available. All farms must have monitoring systems that alert the farmers if systems fail, with most having automatic switching systems to activate backup equipment.

Production cycle. Broodstock are collected from the wild. Spawning time varies between location. For South Australia, blacklip are in spawning condition in winter and early spring while greenlip are in condition in spring and early summer. Greenlip in Tasmanian waters are in condition in late spring because rises in water temperature lag those in the northern waters. Abalone are cued to spawn primarily by changes in temperature. Male and female abalone are identified by gonad colour, which is green in females and pale yellow-grey in males. The broodstock are transported back to the hatchery and the sexes separated into tanks.

UV-light-irradiated seawater is used to induce spawning, which takes about 4-8 hours to complete. Males usually spawn first and will continue to eject sperm for several hours. Females spawn in pulses with eggs negatively buoyant and green/grey in colour. Eggs are siphoned, cleaned and fertilised with the right quantity of sperm (Fig. 1). A single female can produce several million eggs.

The eggs hatch, releasing larvae, approximately 24 hours later depending on water temperature. Larvae, which are free swimming and do not feed, pass through multiple development stages before they are ready to settle. Settlement occurs 4-10 days after fertilisation. Larvae ready to settle are transferred to tanks which have surfaces that have been preconditioned with microalgae. The microalgal biofilm on the surface is believed to induce the abalone to settle. The settlement period has the highest rate of mortality (Fig. 1), with survival being 5-20%, with the average towards the lower end of this range. Abalone feed on the microalgae (predominantly benthic diatoms) whose growth is managed by the farmer through control of light and nutrients.

Abalone are removed when they are 5-10 mm and transferred to nursery tanks. A typical nursery tank holds 20,000-30,000 animals. Abalone are fed on a manufactured diet from this period on. Some farms still supplement with macroalgae, but the inconvenience and handling costs make this less economic. Feed is supplied at the rate of 1-3% of body weight depending on temperature. The feed-conversion ratio (ratio of feed intake to meat gain) ranges from 1.3-1.5 and feed presently costs approximately $2500/t.

Once abalone reach 20-25 mm they are transferred to grow-out tanks. Tank water turnover ranges from every 2 hours to 30 minutes. Aeration is supplied to tanks as a backup if the water stops. Aeration also assists in removing faecal material by keeping it in suspension.

Abalone remain in the grow-out tanks from 2-3 years. They may be graded once or twice during this period, but the aim is to minimise handling.

Pests and disease control

Abalone farming in Australia and overseas has been relatively free of pests and diseases.

Two main pests have caused some problems in Australia. Sea-based farms have had problems with the polychaete, Polydora sp. The common name is mudworm. It affects the abalone by boring into the shell which the abalone repairs by forming a blister over the worm cavity. The mudworm do not consume the abalone tissue, but infected abalone are weakened and more susceptible to stress. If the infection continues the result can be a mortality rate of over 60% in sea-based farms. Land-based abalone farms have had few mudworm infections. Farmers manage this by removing infected stock. Farmers have found when abalone are kept in fast-growing conditions with good water flow they can overcome the infection and eradicate the mudworm.

Perkinsus olseni, a protozoan parasite, occurs in two main locations in Southern Australian waters. Perkinsus results in pustules within the foot muscle and, in severe cases, causes death. There is no known chemical treatment for the condition. The only known management method is to reduce the water temperature. If infected abalone are grown for over 6 months in waters kept at 12°C, the abalone can overcome the infection. This solution is not feasible for land-based farms that may have annual water exchanges of 5-100 ML/day. The only way Perkinsus can enter farms is from wild stock. It is therefore essential that farmers inspect all broodstock collected from the wild and keep them isolated from cultured stock. In South Australia, farmers take care not to collect broodstock from areas known to be infected with Perkinsus.

Harvest and handling

Abalone aquaculture product is sold either live, fresh frozen or for canning. The first usually involves direct sale to wholesalers in Asia, the other two methods involve selling to local abalone processors.

Preparation for live harvesting of abalone commences with cessation of feeding several days before shipment. It is important that the gut is empty at harvest. Abalone are harvested using a spatula that is quickly pushed under the foot. This is done in either the early morning or late afternoon to reduce temperature stress. Some farmers have tried using warm seawater to encourage abalone to drop off the tank's surface, but this method increases stress. No chemicals are allowed during harvesting.

Abalone are usually harvested from their tanks the day before shipment and placed in a holding tank with good water exchange. This is done to identify and remove any abalone that may die as a result of being cut during harvesting. Abalone do not have a blood clotting agent so any cut is potentially lethal.

It also makes it easier to pack the abalone on the shipment day as harvesting may take several hours the day before. Abalone are packed in foam containers (airline approved) inside plastic bags.

Within the plastic bag a damp cloth is placed but no water, as excess water will kill abalone during transport. The plastic bag is filled with approximately 20-30% medical grade oxygen and sealed. This bag is placed inside another bag and that bag sealed. Oxygen is required only for transport periods greater than 12 hours. A further refinement is to pack abalone in pairs foot to foot and wrap in damp cloth. This is done only for larger abalone.

It is important to test shipping methods without product to ensure that the foam containers will arrive on time according to the air schedule chosen.

Fresh-frozen and canned product can be harvested on site and placed immediately into an ice slurry that results in death while maintaining tissue quality. Product is then delivered immediately to processors.

Economics of production

Abalone farming is a medium-to-high-risk venture. The reasons are:

1. a single system failure will kill a high proportion of the stock (large abalone die first) which are dependent on water and aeration for survival;

2. the development cycle in Australia has only just completed pilot-scale production;

3. the full production cycle takes over 3 years;

4. the break-even period for pay back has been estimated to be between 8-9 years; and

5. while several farms are selling product, a complete economic analysis of their production costs will not be available until the end of the pay-back period.

Because abalone farming is relatively new, and farms are being developed in a variety of ways, no single analysis would cover the economic situation. Most farms (hatchery based) being developed are quite large, requiring investment of several million dollars. Owners are protective of their business plans.

The development of grow-out only farms has just commenced, with the guarantee of seed supply from the hatcheries. This type of farming will be more suited to smaller investors.

The economic outlook remains positive. Importantly, most business plans were developed in the late 80s early 90s for the current Australian farms and based their internal rate of return on a price of between $25-30/kg.

Since then, the price has increased and the cost of production has declined because of improved grow-out systems and faster growth rates. Further, hatcheries are developing new markets for their product with the development of grow-out only farms and the demand for larvae and seed for stock enhancement of wild fisheries.

Farms are now selling juveniles (10-20 mm) for between 2-10¢/mm depending on volume and larvae for $1000/million.

Key contacts

Key references

FAO/UNDP 1990. Training manual on artificial breeding of abalone (Haliotis discus hannai) in Korea DPR. Training Manual 7, FAO/UNDP Regional Seafarming Project, 105 pp.

Fleming, A.E. and Hone, P.W. (Eds) 1996. Abalone aquaculture: Proceedings of the 2nd International Symposium on Abalone Biology, Fisheries and Culture. Aquaculture (special issue), 195 pp.

Hahn, K.O. 1989. Handbook of culture of abalone and other marine gastropods, USA. CRC Press, 348 pp.

Hone, P.W., Madigan, S.M. and Fleming, A.E. 1997. A hatchery manual for Australian Abalone. South Australian Research & Development publication, Adelaide, 42 pp.

O'Donghue, P.J., Phillips, P.H., and Shepherd, S.A. 1995. Perkinsus (Protozoa: Apicomplexa) infections in abalone from South Australian waters. Trans. R. Soc. S. Aust, 115, 77-82.

Uki, N. 1989. Abalone seedling production and its theory (1). International Journal of Aquaculture Fish Technology, 1, 3-15.

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