Paua Farming in Northland
Moana New Zealand is ensuring traceability and sustainability in its paua production process
When the rest of the world was struggling with pāua breeding and finding innovative and affordable technology, OceaNZ Blue was succeeding, and 14 years on it remains a growing aquaculture venture. Markets have become highly competitive so again OceaNZ Blue is looking to innovate and adapt – streamlining their sustainable environmentally friendly operation and marketing their tender, and unique colourful pāua to the world.
Established in 2002, OceaNZ Blue limited was NZ’s first commercial paua farm. The OceaNZ Blue Abalone farm is located next to the Niwa Bream Bay Aquaculture centre and utilises the same water intake pipe. Aotearoa Fisheries bought the farm in 2013. In June 2016 Aotearoa Fisheries became Moana New Zealand.
The company innovated early, developing a unique water purifying system at a fraction of the price of what was available at the time. The farm utilises the water intake pipe from what was the Marsden Power Plant where they take 1,500 litres of water per second. Water is filtered and cleaned both coming into and going out of the plant. Outgoing water is run through a rotating drum filter and UV disinfection channels to assure the health of the local Bream Bay and the health of the pāua.
The farm is presently producing 80-90 tons of pāua a year and the company is expanding with a view to lifting production to 120 ton per year. About 15% goes to the local market and the rest is exported offshore, predominantly to Asia, Hong Kong and China. Secondary exports are Europe, followed by the USA.
Recent years have seen a fall in demand for pāua exports. This is due to the technology and techniques being improved internationally and a related expansion in pāua farms around the world. Further anti-corruption crackdowns in some countries where pāua was a popular gift have also impacted the market. The Chinese market especially prizes pāua. It was regarded as the food of emperors and is a high status food that is used for gifting and a show of appreciation.
OceaNZ Blue are now looking to better position their unique product in this competitive market. While other countries are able to produce cheaper pāua due to lower costs, traceability and sustainability are becoming increasingly important to the consumer and here OceaNZ Blue has the edge. OceaNZ Blue product has always been environmentally friendly and sustainably farmed. The pāua are disease free and all water put back into Bream Bay is thoroughly cleaned so the Bay remains a safe swimming beach.
The company is presently completing the paper work in order to achieve certification by the Aquaculture Stewardship Council. The ASC certificate will assure consumers that the pāua comes from an environmentally sustainable and socially responsible farm. They have not had to change anything within their farm processes in order to comply with the standards demanded by this certification.
New Zealand has three native species of pāua – all unique species of abalone found only in New Zealand. Many countries have their own unique species but New Zealand’s pāua are distinguished by a black outer ‘skin’ and an iridescent colourful shell. The creamy white flesh is more pronounced in the farmed pāua – this is due to selective breeding and a diet that is low in melanin.
OceaNZ Blue are also accentuating the unique features of NZ pāua such as the tender texture and the shell. Their pāua remains in the shell when snap frozen in order to display a key point of difference – the iridescent colours of the NZ pāua shell.
Farming pāua is not without it’s challenges. Operations manager Ryan Lanauze says that while “pāua are reasonably forgiving” in terms of water temperature and pH, it’s getting optimum conditions right for growth that presents challenges. Growing pāua to optimum size within the 4 years means that they are constantly refining the technology for each size pāua from season to season.
For example, the recent El Nino summer has meant higher water temperatures and the pāua took a 2 month hiatus from growing. Now they need to catch up these 2 months. Methods to increase growth include:
Grading the pāua so the bigger ones don’t force the smaller ones out to the edges where food is less available.
Feeding the right amount of food for the size and water temperature (pāua will happily eat 3 times what they need but they do not grow at a faster rate when over fed – they simply excrete it).
Balancing the protein and carbohydrate needs of the paua.
Thinning out runts very early.
Of note, pāua are hemophiliacs – they will bleed to death if ‘ripped’ from rocks or trays. As such pāua need to be anesthetized when they are moved on the farm. This is done with Epsom salts in the water. They then drop off from the trays and can be moved safely.
The farm process starts with the broodstock. The original broodstock some generations ago was gathered from Stewart Island to the Chathams and Northland. This assured good genetic diversity. The generations and broodstock are all carefully tracked to allow for ongoing selective breeding.
Broodstock are conditioned in tanks where they’re fed seaweed. The pāua needs the right foods and water temperature conditions to develop gonads.
After 6 months, spawning is induced by adding chemicals to the water that mimic a storm. The subsequent spawning of eggs and sperm are captured in buckets.
These buckets are then combined as desired and added to a water column. Here the spat grow for a few days and then they are moved into an ‘A tank’ for feeding on algae. They settle on the base of the tank.
After 6 months these juveniles are then weaned from algae onto an artificial food and moved into the big ‘Vee tanks’.
After another 6 months – when they’re just over a year old, the pāua are moved into tub tanks with wave action that mimics a rock pool.
After about 2 years when they’ve reached 60mm they’re moved into trays to finish growing.
They’ll spend the final year of the 4 year cycle growing to maximum size – 75-85mm.
The harvested pāua are introduced to cool water to relax them. This assures tender meat and that they do not try to right themselves when laid out for freezing.
The pāua is then frozen using a cryogenic (nitrogen) freezing technology. This assures the meat remains very tender and top grade and can be used raw by the chef or consumer for dishes such as sashimi.
Some pāua is exported live while some is sent to Christchurch for canning, although market forces have seen the demand for canned pāua reduce.