Traditional farming has been the only method available, using existing or cultivated dams and allowing the yabbies develop at their own pace. This is a hap-hazard affair.
EDU Aquaculture® has now developed the Extreme Density Unit (EDU) system of farming, a totally controlled growth environment producing a consistent, market-ready product in a quicker time frame.
The EDU is provided as a ready-to-run kit, supplied complete with everything you need, including the initial yabby stock.
WHAT IS IT?
A brief Overview of the EDU™ system and the EDU Aquaculture® technique to cultivate yabbies.
An indoor recirculation system that houses yabbies in a three dimensional grid allowing for maximum density grow-out. Employing this method of production, over 1000 yabbies can be cultivated in only one square metre of floor space (for yabbies weighing 50 grams). The yabbies are housed throughout their growing period within ‘Strata Cells’.
The EDU is a true ‘Dual Specie Grow-out System’. Various species of Cherax have shown acceptance to the strata cell environment as well as various species of fish (eg. Bettas, otherwise known as Siamese fighting fish). Free swimming fish also serve a valuable function within the EDU system, they aid in water movement and as a perceived aggressor to the yabbies, thereby ensuring the yabbies are well exercised and therefore hungry. Various sizes are available for industrial or backyard/hobby growing. Attachments such as vermiculture and horticulture also aid in water quality, heating and removal of nitrates.
GROW-OUT DENSITY COMPARISON
Comparison of three farming techniques, yabbies harvested from 1 m3 of water per season.
|10 small||25 small||1008 small|
|5 large||15 large||281 large|
It can be seen from the figures above that the output from an EDU system far exceeds traditional methods (dam & intensive).
Up to a 10,000% difference for EDU farming over traditional dam based farming can be achieved!
Traditional farming requires a lot of land to build and maintain adequate dams, it needs to be of the right soil type to hold the water volumes required and has to be within the right areas to assist in distribution of the final product. Yabbies are hardy creatures; they proliferate in what we would consider murky conditions and are generally good, self maintaining breeders. They can however, be affected by stress. Combined problems of overcrowding, limited feed and bad habitats can cause stress levels to be at a point where they die. High mortality rates of up 95% are considered acceptable in traditional farming techniques and for those that do make it, harvesting often damages the yield, breaking claws or legs which make them undesirable for market.
Strata post with 18 Strata Cells attached
Strata posts hanging in EDU system
WHAT IS THE YIELD PER M2?
(Based on industrial size tanks that are 1.5m deep)
- 75Kg with yabbies weighing 50 grams each (1,516 yabbies per m2)
- 80Kg with yabbies weighing 200 grams each (412 yabbies per m2)
- 50Kg with perch or cod weighing 500gm each (Up to 100 fish m2)
CARRYING CAPACITY OF THE EDU SYSTEM PER M3
(Fish are not considered in m3 volume calculations)
50 grams = 50.4Kg per m3 or 1,008 yabbies
200 grams = 56.2Kg per m3 or 281 yabbies
The EDU takes yabby farming indoors. This allows total control over the weather conditions, lighting, water quality and even security during the full development of the product. Productions of high densities are possible because this technique provides for a 3D dimensional population.
|Pic.3 EDU™ 3D strata cells
(20gm Cherax destructors)
|Pic.4 Start and finish sizes for
small strata cells (6 to 50+grams)
The Extreme Density Unit (EDU®) was developed to resolve problems that traditional farming techniques encounter for example, from predators (nearly every living thing around them at some stage in their life cycle), drought, theft, seasonal variations and natural tendencies to wander just to name a few.
Water temperature is maintained at an optimum level and lighting simulating the seasonal condition to accelerate their growth cycles can be monitored. These variables can be adjusted to provide the best possible conditions for breeding and growth.
Water quality is important. Dirty water in dams is normally an advantage to the yabby; if they can't see each other then they are less likely to fight and damage themselves. At the time of harvest however, these yabbies must be cleaned and purged to make them suitable for the market. The EDU uses a technique to separate each individual yabby so this damage does not occur. Clean, clear water can be used during the growth cycle. Cleaning and purging is no longer an issue during the growth process because the contents of the Strata Cell can be easily inspected and sized without any difficulty.
Feeding is a controlled procedure. At regular intervals, a high growth feed is provided to promote it's full growth potential. This is increased over the lifespan of the yabby as it grows and requires larger amounts of food. Farmers calculations are based upon a 2% feed ratio over total bio-mass of the EDU tank.
Eg. 2% of 100Kg of yabbies in tank = 2Kg feed to be dissolved in feeder.
Harvesting is quick and cost effective. Traditional methods require netting/trapping the stock in the dams, returning the various sizes and qualities of available stock for later sorting, purging, sale or discarding. As yabbies are kept in individual cells in the EDU, removal of each high quality, pre-purged and sorted unit is quick, easy and efficient.
Large dams in distant paddocks covering hectares of space are prone to pilfering. Aside from birds, eels and fish that can easily enter a dam, it's not uncommon for looters to net a dam and head off. By being fully indoors, the EDU is as secure as the locks and alarms in the building.
Culture or purge?
The EDU can be used not only as a ‘Aquaculture unit’ for yabbies, but also as a ‘Purging unit’. The difference between the two is that the /A - Aquaculture unit, is used to CULTIVATE or grow-out yabbies from juvenile size, as opposed to the /P - Purging unit which is used to CLEAN pre-existing dirty dam stock.