| | There is a WA industry association called the Silver Perch Association of WA, which is based in the metropolitan area. For information on the association contact the president, Mr Glen Whisson on (08) 9299 7306. From a farmer's perspective, such industry groups are vital sources of the latest information. Since silver perch is an exotic species to WA, there are concerns about its escape into rivers in the South-West. However, in man-made and isolated pond situations, the species is one of the more promising temperate to subtropical aquaculture species for inland WA. The total production of silver perch in Australia in 1996/97 was 114 tonnes with a value of approximately $1.0 million. The required market size of this product is >500g which sold for $10 to $15/kg as live product (Lambert, 1998). It has been estimated that all production could be sold to the live fish trade at around $13/kg or on ice at $5 to $10/kg. At these prices, interest in the species for aquaculture is strong as production costs in the longer term are expected to fall, while wild catch fisheries of other species are expected to experience a fall in tonnages and a subsequent price rise (NOFARIC, 1995). In WA, the Asian restaurant trade is the main market for silver perch for fish over 500 grams being preferred. In 1997, live silver perch sold for up to $22/kg retail ($17/kg to the grower). The local market demand is variable and difficult to predict (Herbert Lee, Han Palace, pers. comm.). Higher production levels are required before a cooperative marketing strategy can be implemented in Western Australia. In the shorter term, a major impediment is inadequate fingerling production in WA and excessively variable survival rates in growout ponds. The industry is yet to achieve significant export sales so there may be a need for expansion into this market as production increases. If the industry can keep production costs down, silver perch could become an import replacement for other species. However, the silver perch industry will only grow successfully if it can address several critical success factors, principally product quality management, training needs and the promotion of this new freshwater product to consumers (NOFARIC, 1995). According to Lambert (1998), the considerable commercial research and development work undertaken to date on silver perch has enabled detailed comment on the advantages and disadvantages of farming this species: Advantages- Hatchery techniques for large scale production of juveniles are well established and simple;
- Silver perch has a very high fecundity so only small numbers of broodstock are required;
- Silver perch is easily weaned onto an artificial feed, and once weaned remains amenable to artificial feeding;
- Survival rates are high;
- If graded regularly, fingerlings have rapid and uniform growth;
- The species is not cannibalistic;
- The fish is omnivorous, which provides potential for relatively low feed costs and good food conversion ratios (FCRs);
- It has a relatively high meat recovery of approximately 40 per cent;
- The diseases under hatchery, nursery and intensive growout conditions are known and manageable;
- The fish has a firm, white flesh with few bones.
Disadvantages- The fish readily takes up off flavour compounds present in the rearing ponds;
- Silver perch require post-harvest purging to remove off flavours;
- Silver perch is sensitive to rough handling and is damaged when crowded;
- The fish is sensitive to oxygen levels below 2 mg/L;
- Silver perch has been poorly farmed and sold both in Australia and South-east Asia, causing considerable and perhaps irreparable damage to the market potential;
- The fish lays down substantial fat deposits in the gut cavity;
- Silver perch is a favourite target of predatory birds.
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