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By encouraging natural attrition, after per kilo (60-70g approx) and at certain Abalone ready for the market six days on the yolk sack, they ���nish times of the year 10-12 (85-100g up with around a million spat settling approx). The most popular size is the in the nursery on the sheets that have 18-20mm. been inoculated with the micro algae To maintain a regular weekly supply, Ulvella lens. They���re then fed a diet Joel commences harvesting after two of different benthic diatom species, years. Harvesting is completed at the but primarily Navicula. The sheets are end of the third year. ���Everything is off 300mm x 600mm and they are ideally the farm at the end of three years. We stocked up to 40 spat per sheet. They hold a bit back for the Christmas rush, run more than 25,000 sheets in the but we don���t carry the larger/older nursery. stock through another summer. We���ve Grading in the nursery in March found the larger stock stress a bit in the culls another 30 percent, leaving warmer water.��� 700,000 to be stocked in the 50, Prices have eased back from the heady 3m x 1m weaning tanks. The water levels of the early days when $50/kg temperature has by this time dropped was the accepted farm gate price. The down to 19 degrees Celsius. Once they high Australian dollar and international have settled, the spat are weaned onto competition have forced down the an arti���cial diet. They are grown in the benchmark export price, but their weaning tanks for another six months before being graded a improved technology, building on experience and research, has second time, at which point the best-performing 50 percent also reduced the cost of production. Feed prices and ef���ciency will be moved to the growout. The rest are culled. have also added tremendously to the reduced cost of production. Fortunately, the major ef���ciencies learned by trial and error are behind them says Joel. While margins aren���t GROWOUT Growout is carried out in 40,000 litre shallow, 0.5m deep exorbitant, they���re healthy, the farm���s output is now more concrete tanks, with a diameter of 10m. Ocean Wave use 59 predictable, and the markets have settled down to a constant ���ow. The future looks stable for Ocean Wave Seafoods ��� of these tanks. Growout times have improved dramatically over the years.The a just reward for their tenacity and hard work. early timetable was four to four and a half years. Improvements in husbandry methods based on experience and observation Joel Gilby can be contacted by email on joel@oceanwaveseafoods.com have made an impact, so too have selective breeding programs. While dealing with a wild animal suggests immediate chances for improvement from careful selection, there���s still the need for performance comparisons and stock management. One of the biggest improvements has come from improved feeds. A Cooperative Research Centre program between industry and Fisheries Research and Development Corporation-funded nutritionists, has not only improved the ef���ciency of the available rations, but has also dramatically reduced the cost. They use Adam and Amos feed from South Australia (Adam & Amos Abalone Foods Pty Ltd). Feed conversion ef���ciency is a healthy 1.2-1.3. ���We could probably do a little better, but we don���t underfeed. We���ve found it better to keep Providing the New Zealand the growth rates going rather than skimp on feed to save a aquaculture sector with a few dollars,��� Joel said. comprehensive range of diagnostic At weaning, the abalone are fed a starter diet of 35 percent and food testing services, including: crude protein and three to ���ve percent crude fat until they Parasitology reach 25mm at 12 months old. After that, they are fed a ration Haematology of 30 percent with a crude fat value of four percent. Bacteriology Water temperatures can be a problem, especially in these Biochemistry times of extreme weather events. At the peak of the summer Toxicology they can get as high as 23-24 degrees Celsius. Joel reduces Necropsy feeding during these times and maximises water ���ow. He also Histopathology adds extra aeration in the tanks to keep the dissolved oxygen General health screening levels as close to saturation as possible. So far they haven���t Diagnostic interpretation had any major disease outbreaks and have managed to dodge and consultation Nutritional value analysis the herpes virus outbreak that took such a toll of the farms Feed testing in Bass Strait. After two years the harvesting begins, by which stage 20 percent have grown to 50g, or 65mm. Aquatic laboratory services MARKETING 0800 GRIBBLES (0800 474 225) Email: aquatic@gribbles.co.nz www.gribblesvets.co.nz VIP.AC45 Ocean Wave has based their marketing on being able to supply their clients throughout the year. They have three marketing grades: 18-20 per kilo (55g-50g approx), 14-16 MARCH/APRIL 2013 ��� NZ AQUACULTURE ��� 15