Queensland Crayfish Farmers Association - Links and Trade Directory

Queensland Crayfish Farmers Assoc.
Getting Started: Congratulations on your decision to consider joining one of the newest and most exciting emerging growth industries in Australia!! The way not to make a success of being a redclaw farmer is to dig a couple of ponds, throw in some redclaw and sit on the verandah dreaming of the money rolling in. You must realise that it is a primary industry and like any other, is subject to its ups and downs, being dependent on climatic conditions, external influences and the vagaries of the animal itself. The Degree of a success enjoyed by any redclaw farm is proportional to the amount of effort and diligence exercised by the farmer. It doesn't take a lot of money to operate a redclaw farm, but it does take a lot of capital expense to build one. Don't forget you have to live for two years without income before production is at a supportive level. We recommend a minimum of 5 and preferably 10 hectares of pond area as a viable family business sized farm. Farms of much larger size would be required for anyone wishing to be a force in the industry. Following the trend of our web page, we have called upon the expertise of various members and of the Queensland Department of Primary Industries to contribute to this section.
Pond Design and Construction: Having designed and constructed our own farm and been involved first hand in the construction of several other farms, I have gained some knowledge on the subject and I share with you the following determining factors regarding site selection and farm layout, pond design and construction methods. Site selection: There are two essential ingredients required in determining whether an area of land is suitable for aquaculture, these being access to a reliable supply of suitable water and soil/sub soil with the characteristics for successful pond construction (non permeable clay with stability under saturation.
Water Supply: When choosing a site, water availability/quality is possibly the single most important factor. This water may be sourced from a bore, river or surface of run-off stored in a large dam or ring tank. The chosen source should be able to meet not just your start up needs - i.e. 1 ha. but also your future possible requirements - i.e. 5 ha. Land usage in the catchment area of the water supply should be investigated as certain industry practices may prove the water to be less than ideal for the required needs. A sample of water should be taken and be professionally analysed. Soil/Subsoil: An ideal site should consist of a shallow depth of top soil covering a good quality clay based material to a minimum depth of 3 metres. A soil profile test should be carried out at regular spacings across the potential site. This can be done by simply using a small hand auger(50mm) on a series of extensions, drilling into the ground until the required depth is achieved. A seepage test should also be carried out, this can be done by boring some holes, again at regular intervals across the site using a post hole digger. These holes should be cleaned out and filled with water. What happens to the water over the next few days will give a good indication of the material's ability to hold water. A soil analysis should be carried out to ensure the proposed site contains no sinister contaminants.
	Other factors to be considered: 1 - topography of land (suitable slopes, non flooding) 2 - access to markets/transport 3 - suitable gravel (if gravel ponds are desired) 4 - neighbouring land usage Farm Design and Layout: Once the site has been chosen and suitability determined, the planning of the development can begin. Many aquaculture ventures start small and grow into much larger operations as time passes and here lies a common problem - future expansion is not catered for in the original planning. A total farm plan (maximum farm area) should be concieved prior to project commencement.
The proposed farm should then be separated into 5 portions, these being: 1 - brood ponds (where all juvenile production requirements are met) 2 - juvenile growout ponds (where juveniles are placed once harvested from brood ponds and allowed to grow to a size where sexing takes place) 3 - market growout ponds (where single sex stock can be placed and grown to the chosen market size) 4 - drainage sump (a low area or purpose built sump suitably located where pond discharge water is captured for reuse) 5 - handling and packaging shed (suitable to handle projected harvest quantities) The previous list contains all essential components of an efficiently run farm and should all be treated with equal importance, they should be arranged and positioned around each other to facilitate ease and efficiency of operation. This plan can be broken down into stages of construction.

Pond Design: Pond size - Various sizes may be chosen e.g. 1000 m2 for juvenile production and 2000 m2 for market growout. One determining factor in deciding on pond size is available labour at harvest, as smaller ponds are much easier to handle on a one person operation than larger ponds. Cost per ha. also varies with pond size. 10 x 1000 m2 ponds cost more than 5 x 2000 m2 ponds in earthworks alone as more material needs to be moved. Also smaller ponds require slightly more land area, increased duplication of aeration outlets, water outlets, drainage outlets, harvest sumps etc. However smaller ponds are much easier to manage and the larger number of ponds offers a greater range of management options. Pond shape - It is generally agreed that rectangular ponds are preferred as opposed to square shaped ponds e.g. 50 X 20 or 100 X 20, long narrow ponds are much easier to feed and this shape allows the pond to be sloped more effectively into a confined collection or harvest area. Gently sloping sides allows a prefered environment for crayfish culture. This design allows shallow areas for feeding and moulting and deeper areas preferred on hot sunny days (preferred thermocline). Pond depth - Pond depth varies as the long sides slope towards the pond centre line and the short tend to be - one, the deep end and the other the shallow end. Maximum pond depth need be no more than 2.0m and a depth of 1.0m is the desired depth at the shallow end.
	Drainage - Bottom draining ponds have a distinct advantage over non draining ponds in both management and harvesting options available. A harvest sump made of concrete and besser block should be positioned in the deepest part of the pond, in which a pipe (150mm) is set, which in turn is connected into a common (to all ponds) drainage pipe which carries the discharge water to the drainage sump. The size of this common drainage pipe is determined by the total area of ponds connected, as the pipe must accommodate pond overflow during major rainfall events that the location of the farm may experience. Acceptable allowable drain down time is also a factor worth considering, as the larger the pipe the quicker the pond shall drain and vice versa.
Bank width/height (above water) - Bank width between ponds needs to be sufficient to allow access of harvest, feeding and maintenance equipment. A main access bank between pond rows (short side) should be of no less than four metres with the bank between ponds (long side) 3 metres. The height of bank above water or free board should be no less than 200mm, with a height of more than 400mm considered unnecessary, around 300mm is ideal provided an adequate overflow system exists.
Construction: Once the site has been chosen and the design and layout of the farm determined, construction can begin. The first thing to do is survey the site and determine where the ponds shall be positioned in relation to the natural ground. This process can be quite a technical and time consuming job, but one of utmost importance to the success of the project. it must be decided how the ponds shall fit the chosen site.Iif the area of land is gently sloping, are the ponds to be constructed all at the same level with the ponds at highest point being set almost entirely into the ground, using this excavated material to construct the ponds at the lowest point almost entirely above ground, or, are they to be stepped to suit the natural slope?
Cut and fill quantities need to be determined as it is that which decides the final height of the ponds above natural ground level. If a drainage sump is to be excavated this borrowed material must be factored into our cut quantities. This is essential information as it determines the depth into the natural ground at which the pond drainage is to be set. This plumbing can be installed after the ponds are completed however I believe it to be easier prior to pond construction commencing. Having established cut and fill quantities and the profile of the ponds we can then peg our site. First thing to do is drive in a peg at a set height to use as a datum point, a point that never alters and can be continually referred to during the construction phase. This datum point is used to determine top of bank heights, pond bottom depth and the relationship of these to the preset drainage. To peg the ponds simply place marker pegs outside the perimeter of the site marking all bank centres creating imaginary lines on which to form the pond banks. Material usage and bank construction method is important for the ablility of the ponds to successfully hold water. Along pond bank centers all topsoil should be stripped exposing the non permeable clay based material into which the banks are to be keyed. The banks are to be constructed using the excavated clay in the centre or core of the bank, with the stripped topsoil used as the outside layers which shall promote grass growth and stability once established. All material used to construct the banks should be run out in layers no greater than 200mm loose and highly compacted. Remember, this is just one opinion and as in everything, there are many.