OCTOBER/NOVEMBER 2004
– are produced in a number of hatcheries using wild-caught or farm-grown broodstock. Spat for the WA farms come from Trevor Sweetman’s Bealwood Pearl hatchery at Carnarvon and the Geraldton-based Elmwood Holdings hatchery. Wild shell are collected by licensees with an ‘Oyster Fishing Licence’ which permits collection of a limited number of adult pearl oysters for use as hatchery broodstock. Eight of the 40 or so non-maxima licensees are authorised to conduct hatchery operations including several TAFE colleges. Although 7,000ha is currently licensed for non-maxima pearl culture, a fraction of that is actually under culture with a number of farms still under-developed stages or awaiting capital injection. WA Department of Fisheries’ Aquaculture Policy and Industry Relations Officer, Andrew Beer, believes that black pearl production may be the third most valuable aquaculture industry in the State – after P. maxima pearling and the marine algae industry – within two years. Around 5,000 black pearls were harvested in WA during 2002/03 and over 35,000 shell seeded in that same period. Harvests of 50,000 pearls per year are predicted in the next two years. That will allow growers to build market value through access to enough pearls for building the well-matched parcels of product necessary for necklace strands and other jewellery. Whilst a pearl on its own is limited in value, alongside 20-30 others of the same colour and grade, the whole is significantly more valuable than the sum of the parts.
An added bonus is the hues of the Abrolhos black pearls – silver, green, peacock and aubergine – quite distinct from the greys, greens and blacks of the Pacificproduct. The bigger the batch the more noticeable the variation. This has boosted demand for the WA black pearls with finished jewellery being snapped up by eager buyers, both in Australia and overseas. “One European buyer is rapt with the aubergine colour of our pearls,” explains Don Woodcock, owner of Abrolhos Pearls with his father Alf and partner Murray Davidson. “The buyer said that our pearls were ‘absolutely fabulous’ and is coming over this October to visit the farm.” Culture techniques are basically the same as for P. maxima. Surface longlines (100 to 250m long) are strung some 20 to 40m apart in around 10 to 33m of water. Around the Abrolhos Islands there are many coral bommies which rear up from deep water to the surface. The farmers can use these to attach their longlines so long as the net panels do not snag on or damage the coral. These net panels hang down from the longlines 2.5-3m below the surface. The culture cycle starts with the juvenile spat being held in cages of 4” x 4” square metal mesh covered with 1mm plastic mesh; the box looks a lot like a suit case. A net panel is inserted containing 1m of Christmas tree rope supplied from the hatchery. Around 2,000 spat are attached to the rope and grown for a couple of months in the cages. The farmers take the bigger individuals (10 to 15mm) by cutting the byssus
FARM PROFILE
thread. These older juveniles are held in 45 pocket net panels. As they get larger they are held in 15 pocket net panels. Adult shell are considered ready for seeding when they are over 100mm in length. Industry concerns Many of the black pearl farmers have diversified from rock lobster or scale fish fishing allowing the use of existing infrastructure – specifically million dollar, state-of-the-art workboats (often up to 25m in length) as well as the many island ‘camps’ (complete with access jetties, accommodation, refrigeration, power) scattered throughout the Abrolhos Islands. Given little or no expertise in pearls and the consequent need to develop techniques by ‘trial and error’, progress of these farmers has been slow and a burden on cash flow. Being a small and close-knit community, members of Geraldton’s Central West TAFE Marine Industry Advisory Committee heard of the industry’s challenges. This resulted in a mid-2003 review of the industry that showed that the local farmers had the basic knowledge and skills to establish their farm and grow the shell for seeding. But they did rely on highly skilled interstate and overseas technicians brought in to seed the shell for a period of two to three weeks before moving onto another pearl farm. The farmers then had to nurture the seeded shell and await the return of the technicians some 18 to 24 months later for the harvesting of the pearls. The review also found farmers lacked
From left: Pia Boschetti practising the cutting of small pieces of mantle tissue for use in seeding. This net panel shows some of the fouling organism that can attach to the net and the shell. Bernie Aquilina (seated) demonstrating the aspects of the seeding process, using a television monitor via the endoscopic camera probe. Photographs courtesy of Berni Aquilina.
A U S TA S I A A Q U A C U LT U R E
15