NIWA has been at the forefront of paua (abalone) aquaculture research for over 20 years.
Scientific name: Haliotis iris
Common name: Abalone
Māori name: paua
Paua belong to the molluscan genus Haliotis that is more commonly known as abalone. The name Haliotis derives from Latin and means sea ear, reflecting the ear like shape of the abalone shell. In other parts of the world abalone are also known as ear-shells, Venus's-ears, muttonfish or muttonshells in Australia, ormer in Jersey and Guernsey and perlemoen in South Africa. The number of species recognized world-wide ranges from about 100 to 130 (due to the occurrence of hybrids). Three species of abalone occur naturally in New Zealand; black foot paua (Haliotis iris), yellowfoot paua (Haliotis australis) and white foot paua (Haliotis virginea). Only black foot paua are currently farmed in New Zealand, which can be attributed to the larger size of the black foot over the other two New Zealand species.
Black foot paua is the largest abalone species found in New Zealand and is most commonly found in shallow waters at depths less than 6 m all around mainland New Zealand and the Chatham Islands. They often form large clusters in the sub-littoral zone on open, exposed coasts where drift seaweed accumulates and there is good water movement. Black foot paua grow to about 180 mm in shell length (legal size for harvesting is 125 mm, measured as the longest shell length)
Why are paua farmed?
In many markets worldwide abalone are considered to be a highly prized molluscan delicacy and fetch a high price at market. Because of their high market value the prospect of aquaculture of abalone has and continues to be extremely attractive. Food and Agriculture Organisation statistics show that worldwide farmed abalone production has reached 22,000 tonnes, with China and Taiwan producing the bulk of this at around 19,500 tonnes. South Africa, Australia, USA and Chile account for most of the remaining production. Here in New Zealand paua are farmed not only for their meat and but also for pearls grown within their shell.
How are paua farmed?
Overseas, a number of other production technologies are used to farm abalone. China and Taiwan rely on low technology, highly labour intensive pond systems where abalone are fed on wild harvested or farmed seaweed. In South Africa, they have opted for land based, pump ashore systems. These systems are highly labour intensive and also rely on seaweed diets. The South African abalone (H. midae) is considered to be one of the most desirable of the farmed species. In Australia artificial diets are used in pump ashore systems that are much less labour intensive than the South African systems. Abalone farming in Chile has developed rapidly in recent years, using sea based systems, and production here is likely to continue to increase.
The New Zealand paua industry has been in existence since the mid 1980’s when NIWA (as part of New Zealand's Ministry for Agriculture and Fisheries) developed hatchery techniques for the species.
Paua farms in New Zealand have traditionally been land-based and configured to operate on flow-through water supply where the water is pumped from the sea, over the paua and then allowed to return to the sea. Currently, the industry in New Zealand is based around 12 farms. These farms are mostly on-shore systems that on-growing hatchery reared juveniles for market size for their meat. The largest of these is the OceaNZ Blue Paua Ltd (OBP) located at NIWA’s Bream Bay Park facility in Northland. OBP is on track to become the first 100 tonne production facility in New Zealand and operates using recirculation technology.
Recirculation technology has gained favour in recent years and offers several advantages over flow through by improving performance, raising efficiencies, reducing costs and reducing risk. These advantages include maintaining consistent rearing temperatures, protecting farms from fluctuating environmental conditions and improving overall biosecurity. Although the trend is towards recirculation, at least two farms currently operating use sea-based barrel culture technology; however, the focus for these is on the production of paua pearls which employs a more extensive approach using fresh harvested seaweeds.
Early efforts on paua commercial production also used seaweeds. However, now most land based farms rely on manufactured pellet feeds imposed on farmers due to the difficulties in obtaining sufficient quantities of seaweed and also the additional benefit of reducing the black pigment in the foot. In the early days the existing export markets for paua required the black foot pigment of paua to be removed; latterly those export markets now appreciate the darker pigment characteristics of the New Zealand black foot product.
How is NIWA research helping paua aquaculture?
NIWA research is addressing three key areas of paua production:
Improving our knowledge of the biological requirements
Although we know much about paua biology a number of questions specific to culturing this species remain unanswered. We are currently undertaking research to gain a clearer understanding of the impact of water quality in commercial culture conditions on paua and to better define the nutritional requirements for this species in culture.
Improving system designs
Our focus is currently on the role of water movement and gas and acidity regulation with paua culture systems addressed through improved understanding of these environmental requirements and development of innovative designs that can deliver high quality water at a commercial scale.
The aim is to progress the reliance of farmed paua stocks are currently derived from predominantly wild caught broodstock. NIWA and OceaNZ Blue Paua Ltd are collaborating to undertake a selective breeding program that aims to significantly improve growth rate and product quality in farmed paua by 2012.
NIWA provide NZQA accredited training courses on paua farming and water quality control in closed systems.
For more information, contact
Dr Philip Heath