During the presentation by Michael I noted down some of the key elements of the breeding process.
- As with Bass and Barramundi hormones are used to stimulate the production of eggs and sperm
- Spawning can be performed anytime between November and May dependant on the availability of the right feeding pond for post spawning.
- Northern Jungle perch breed at a different (lower) salinity level that Southern Jungle Perch.
- Adult breeding stock are initially put in fresh water tanks that are cycled over to sea water over the space of 12 hours.
- Once the eggs are fertilised they are separated and incubated. Fertilisation to hatching is only 15 hours.
- The first two weeks are critical, if larvae get through this period then they have a high survival rate.
- Freshly hatched larvae are fed on Copepod Naupii. Aeration for the fry is via air stones as fry in this stage are very fragile. The team are still working out best containment will work to prevent injury from colliding into the side of the tank.
- Large grow 0.5mm per day
- 6-7 days in they inflate their swim bladders by gulping in air.
- 3-4 weeks in feed is supplemented with powdered food.
- Fingerlings are harvested at 30mm and moved into a larger tank filled with salt water that is cycled to fresh over 24 hours
- Fingerlings are very good at leaping, they can jump through a 1 cm mesh with ease so smaller mesh is used above tank
- As they grow they are trained against predators.
- Wild release at between 50mm and 90mm
- In good conditions fish can grow to 25cm in their first year but in areas of less food it can take 3 years
- Males are sexually mature at 18cm, females at 23cm.
- They grow up to 3.6 km (50cm)
- Jungle perch grow faster than Bass in impoundments.
The news article on the recent release of fingerlings is available at https://www.daff.qld.gov.au/services/news-and-updates/fisheries/news/more-than-1,000-jungle-perch-fingerlings-reared.