Golden Perch

"Review of Golden Perch Aquaculture at Walkamin."

 

This page contains extracts of information taken from the AAQ Conference 2004, presentation by Brett Herbert.

Brett Herbert

Profitable Aquaculture Systems

Queensland Department of Primary Industries

Freshwater Fisheries and Aquaculture Centre

Walkamin

 

STRAINS

 

 

  • Three strains of golden perch in Australia.
  • Most commonly grown and sold are Murray-Darling strain.
  • The Fitzroy subspecies (Central Queensland) is darker than the M-D strain.
  • The Lake Eyre basin species is longer and thinner, and is generally more silver than the M-D strain.

 

MARKET

Colour manipulation

  • As colour is important we tried making fish paler.
  • Using kaolin clay or holding in dark conditions did lighten the colour.
  • Over three days they darkened.
  • A light coloured chill bin produced lighter coloured fish closer to wild ones.
  • Lighter colour produced in turbid water.
  • Aquaculture golden perch received a slight premium on wild caught when gill & gut taken into account.
  • Market prefers cleaned fish.
  • Lighter colour produced in turbid water.
  • Market of up to 1000t/year. (Sydney/Melbourne), although recently  400T.

Purging

  • Tank purging resulted in significant weight loss (10%) over one week.
  • In pond purging (no feeding for four days) prior to harvest.
  • All ponds sampled before purging started with at least three women involved each time.

Weaning

 

  • Fish which did not wean successfully die off after 10-20 days.
  • Weaning success is usually 90-95%.
  • Small fish (0.15g,19mm) wean as well as larger fish (0.5g,32mm)  

Nursery

  • Grading does not appear to be strictly necessary.
  • About 50% of fish will not perform in aquaculture.
  • These fish do not eat pellet food but do cost in oxygen and ammonia etc.

Grow out

  • Sex ratios –males dominate (60%)
  • Females split into two groups-ones that don’t grow and ones that grow.
  • Body shape significantly different after 150g (♀ heavier).
  • Female growth slower initially but catch up at about 6-9 months.
  • Juvenile ♀ were more susceptible to handling stress.
  • When an average size of 600g+ is achieved, pond is ready to harvest.
  • Fish sizes will range from 350g to 1kg+ (90%>450g).
  • This takes from 14-18 months.
  • Grow out from 200g to market size is relatively quick.
  • Temperatures >15°  100g per month is achieved, sometimes more

Conclusions

  • Feed a sinking pellet, 40% protein.
  • Monitor feeding closely-size, quality, regularity.
  • Maintain water quality.
  • Realise that only 50% of fish may grow, bank on 30%.
  • Sample product before harvest! (Taste)