Topography influences the layout of the farm and the arrangement and type of ponds constructed. The type of soil found at a site will determine how much water will be lost through seepage and so may impact on the ultimate viability of the venture.
Topography:
The area of the land selected for pond farm should be large enough to allow for future expansion in building the maximum number of ponds to provide the farmer with a worthwhile income.
Allowance should also be made for outbuildings and holding tanks. Of course, no expansion should take place until a small-scale pilot project has been successfully conducted on a suitable site on the property.
Ideally, the land should be relatively flat and slope gently with the farm site below the water source to permit supply by gravitation. Otherwise the pumping head should be as low as possible.
Allowance should also be made for a drainage basin for the dumping of unwanted water. The topography of the land will determine the type of ponds to be constructed. There are three basic structural types: excavation, levee or gully.
- Excavated ponds are the most common where a depression is formed and the removed soil is used to build the banks. This type of pond can be built on flat or undulating land.
- Levee ponds are constructed on very flat land where soil is brought in to build up the banks high enough to contain the necessary depth of water.
- Gully ponds are restricted to hilly terrain and are constructed by damming valleys, gullies and creeks.
Ideally, ponds should be square or rectangular to make the most efficient use of available land. It is generally more economical to construct square sided ponds. It is also beneficial to site ponds parallel to prevailing winds to enhance water circulation, turbidity and oxygenation but remembering to construct levees at such an angle that this will not cause excessive erosion by water lapping at the banks.
Whilst still considering topography it is important that there is all-weather road access to the site. Land susceptible to occasional flooding should also be avoided to prevent stock losses and property damage.
Soil characteristics:
The soil at the site should be relatively impervious to eliminate or reduce loss of water by seepage.
- Clay or clay-loam soils are ideal. Loamy soil can be well compacted and may tend to leak slightly in early stages, but will usually seal after a short period of time.
- In some areas where there is a sandy topsoil covering clay, this sand is removed, the ponds are excavated in the clay and a thin layer of sand is then placed back over the surface of the pond. This compacts with time and allows the farmer to walk about on it when it is drained without leaving foot-holes.
- Ponds constructed on land with permeable soil can be sealed with polythene sheet liners, but this is extremely expensive and not very practical as liners can deteriorate after a time.
Geographical location:
Proximity to markets, transport routes and a developed population centre are all important factors to consider, as is the availability of electricity.
Proximity to markets:
If your stock is sold live it can be advantageous to be near your market. If you are in the business of selling juveniles, this may also be an important point to bear in mind. Refrigerated transport is a necessity to ensure fresh chilled product to reach the markets.
Proximity to transport routes:
Being close to a main road is desirable in reducing transport costs for deliveries and dispatch of produce.
Proximity to a developed population centre The need for mechanical repairs, postal and telephone service as well as general provisions make it desirable to be within convenient reach of a major town.
Availability of power:
Although some extensive farms have little demand for power, it may be necessary to have a source of reliable power during initial construction work. Semi-intensive and intensive farms that require pumping and aeration may require three phase power.
Electricity is not always cheaper than liquid fuels as a power source, but the long life and low maintenance cost of electrical motors could give them a compensating advantage over petrol driven engines. Thus, though it may seem to be of little direct importance, the availability of electricity within an area can have a strong influence on the viability of a fish farm.
Other considerations:
After major factors are considered, there are still a number of other questions that need to be asked:
- Is predation and theft a problem and can you economically secure your farm? Bird meshing and alarm systems are expensive and other methods of predation control are time consuming.
- Will state and local land and water management agencies provide you with the permits to carry out aquaculture in your chosen area?
- Could activities (aerial spraying, run-off) on adjacent land cause a threat to your activities?
- Will you need any specialised equipment because of some problem unique to your site?
- What was your farm site used for before and could the soil be contaminated by agricultural chemical residues from previous years?
- Have you made contact with people in the vicinity of your site and investigated the possibility of unusually localised weather conditions that may hamper your chances of success? It would also be advisable to speak to personnel from the Primary Industries Aquaculture SA, other fish and/or crayfish farmers and other research institutions to gather all available information and literature in an effort to gain as much knowledge on the problems you may encounter.
- Have you registered your farm with PIRSA Aquaculture SA and can you comply with the appropriate regulations?
- Is there a demand for your product, what size, what competition are you up against and is there room for market expansion?
These questions will determine the type and size of your operation. Although many of these points may seem obvious, failure to comply with any one or several of them may result in biological and/or economic failure. From personal experience, we have seen many aquaculture ventures flounder or fail completely because of poor management practices, lack of financial planning or technical expertise.
Don’ t hesitate to change your plans if your investigations suggest different or more viable alternatives for the use of your land. Avoid getting locked into a proposal that has no chance of success simply because you’re sick of the 9 to 5 rat-race, the land is cheap or it is near your home. These are not valid reasons for entering into aquaculture industry. The approach should be thorough and realistic.
Information Sourced From:
