Australian Golden Perch
Australia's Golden Perch have been popular as a table fish for generations. Until recently licenses existed for the commercial harvest of golden perch from the Murray River. This practice has been discontinued, with the possable exception of a few licences at the mouth of the Murray River. Almost all golden perch now come from aquaculture. Early in 2004 the first commercial quantities of Lake Eyre strain fingerlings were supplied to grow-out farms. There are three major strains of golden perch. These strains have distinct qualities and perform differently under aquaculture conditions.
There are three distinct strains of golden perch.
This map shows the three river basins for the golden perch strains.
Blue: Murray/Darling River Basin.
Red: the Lake Eyre River Basin.
Yellow: the Fitzroy/Dawson River Basin.
The Murray/Darling River system, Macquaria ambigua ambigua, the Lake Eyre Drainage System, Macquaria ambigua ssp., and the Fitzroy/Dawson River System, Macquaria ambigua oriens. The largest is the Murray Darling System which extends over four states. Starting in Queensland moving through New South Wales and Victoria and finally reaching the sea in South Australia. The Lake Eyre System also drains from Queensland to South Australia where it empties into Lake Eyre and finally just dries up! The Fitzroy Dawson River system is limited to Queensland. It drains a large portion of Central Queensland and empties into the sea at Rockhampton. There has been some debate over which of these strains of golden perch may be best for aquaculture. Some say the colour is the most important factor and that one strain or the other displays the most "gold" colour. Ausyfish has kept all three strains over the years and our experience is that all strains will display good gold colour when kept in the right conditions.
The first commercial supplies of golden perch fingerlings were supplied to grow-out farms in Australia during the 2003-4 season. They were from the Lake Eyre strain. These fish have shown excellent growth. One grower reports that they grow much faster than silver perch. This grower is using large round polly tanks. In his words the fish are described as "..the barramundi of the inland..".
After 40 days the fish had grown from about 1gm to an average size of 25gm. The fish were graded into three average sizes, 50gm, 24gm and 12gm. One fish was 112gms.
After 75 days they are estimated to be an average of 40-50 gm. This is an estimate as the water temperature was 14-15C, and handling was considered an unnecessary risk at this relative low temperature. This grower says they eat actively at 15C, and at 12C still feed but not so eagerly. This is in contrast to Silver Perch which cannot be seen feeding at 14C on the same farm.
After 100 days the average of the larger fish was 108gms. The largest fish was now just over 200gms. The average of the fish in the medium size range, (which is now two thirds of the population) is 80gms. The grower reports that they have gone from 20gms to 80gms in only two months! The FCR, (food conversion rate) over the range of sizes is between .8 and 1.7 to 1 This is using dry food.
They are a little more difficult to handle. The fish have smaller scales and are softer to the touch. When handled for grading or other management tasks, extra care should be taken not to cause any physical damage to the fish as they may become infected. Using graders with metal bars seem to be damaging to these fish. Some improvement has been achieved by increasing the oxygen before handling.
Below is a link to a page which details weaning methods. It should be noted that the variety of golden perch used for the weaning trials were not from the Lake Eyre River System. The Lake Eyre variety of fingerlings were not available for these trials. The Lake Eyre variety is from the same river system as the Jade Perch. Jade Perch are extraordinary performers in aquaculture. It is believed that the golden perch from this river system will also be better in aquaculture that other strains. The weaning of this season's fingerlings proved to be much easier than other strains.
Golden perch is a native Australian fish. It is marketed as callop or yellowfin perch. The market was supplied by wild caught fish, however almost all these licences and permits to harvest these fish from the wild have been discontinued. When the fish were available from wild harvest, Gilled and gutted fish 500g to 1 kg, (up to 4 kg) sold for AUD9-16 per kg at Sydney fish markets. Quantities sold annually varied greatly. Sydney fish market figures were 200 tonnes cleared on the auction floor in 1993, and 4 tonnes in the first half of 1996. Market analysts believe that the total quantity sold in Sydney and Melbourne were at least four times that sold on the Sydney fish market. This indicates that the domestic market can accept large quantities (ie 800 tonnes) of the product.