Embankment is a form of pavement made on the side of the pond. It serves to provide enough support for the pond to prevent pond collapse by water. It also serves as a walk way to the farmer and farm attendants.
This will help the fish farmer to have an easy look at the pond without supporting the leg with anything and will also make feeding the fishes easy and in addition, it adds beauty to the fish farm.
Importance of Embankment Pond Preparation in Fish Farming
The most important component of the fish farming business is to prepare a pond in a proper way especially the Embankment part. Without the construction of a well-prepared pond, it is not possible to start or run any fish farming business. The importance of pond preparation is given below.
- Aquatic plants and animals which are harmful to fish are controlled
- Cannibalistic and unwanted fishes are removed
- A healthy environment of the pond is preserved
- Optimum pH for fish production is maintained
- Availability of the feed for the cultured fish is ensured
Types of Ponds used in Fish Farming
Within freshwater fish culture unit, different kinds of pond components are used; they are nursery, rearing, production, segregation and breeding/spawning pool.
The percentage of area covered by these different pond types are given below:
Nursery pond: 3%
Rearing pond: 11%
Production pond: 60%
Segregation pond: 1%
Breeding pond: 25%
Nature of Different Ponds
Nursery ponds: Shallow
Rearing ponds: Moderately deep
Production ponds: Moderately deep
Segregation pond: Moderately deep
Breeding ponds: Moderately deep
Water level (for larger production ponds): 2-3 meters
Fish Pond Construction
- Before constructing the pond, land is surveyed to find out determine its topography.
- Marking the area of proposed pond is the first step in the construction of a fish pond.
- The natural slope where the main wall is to be built should be ascertained.
- The main wall should be marked off at the lower end of the pond, where the slope is the greatest.
- The first step while designing fish ponds should be to study the soil type, topography and water supply.
- In designing the fish farm, it should be decided as to where and how many nursery, rearing and stocking ponds are to be constructed.
- In case of a fish farm constructed solely for the purpose of seed production, only nursery and rearing ponds may be constructed, with a nominal area for the brood stock ponds.
- In case of grow-out farm, more stocking ponds will be constructed to produce table size fish after stocking fingerlings.
- For a composite fish farm all three types of ponds are required and their number should be based on the intended stocking density.
- Fish ponds should be at least one surface acre in size. Ponds smaller than one acre seldom support a satisfactory fish population over many years. They usually require much more intensive fish management and may not justify the costs.
- It is important to know the exact size, maximum depth, average depth, and water volume of the pond. This information becomes useful in calculating the amount of herbicide needed for weed control and the number of fish fingerlings needed for stocking.
Preparation of Fish Pond and Fish Pond Embankment
1) Preliminary or preparation stage
Before starting other procedures, the soil should be tested. Samples are collected from the bottom of the pond and dike. Generally, pH and organic matter contents are analyzed. pH is important to determine the amount of lime to be treated later. Soil sampling is very important, especially for the new ponds.
One of the most important steps of pond preparation is to “de-mud” the pond, which we wish to prepare. “De-mud” basically is the process of removing mud from the pond which we wish to use. The main purpose of demudding is to make it more suitable for fish farming.
Demudding can be done just by removing the mud from the pond, which is the easiest way. Instead of demudding directly, we can go for deepening of our pond which is the best option for larger fishes.
The bottom of the pond is dried to remove the unwanted fish species. Drying is done until the soil cracks. Drying also ensures the oxidization of harmful substances and mineralization of organic matters.
Make the dike of the pond taller:
The most common problem of the rainy season for most of the ponds is that flood can carry away fishes of the pond. So, if the pond is located in an area which is closer to the river or stream, then taller embankment or dike is a must. It should be at least 2 to 3 ft higher than the highest level of water in the pond.
This can be done very easily and automatically during the time of digging or demudding. Sand removed during de-mudding/digging can be used to make dikes taller. Otherwise, sandbags can be used to make the dikes/embankments taller.
Efficient inlet and outlet system:
Efficient inlet and outlet system is very much important for the proper working of the pond system. This mostly comes in the form of a pipe through which water can enter and exit from the system. The inlet system of the pond should be placed slightly higher than the outlet system to ensure maximum water flow.
Proper inlet and outlet system prevent overflow of the pond by taking care of heavy rainfall/slight flood. This is very much helpful for the proper maintenance of water quality.
2) Treatment stage
Controlling harmful aquatic plants and animals:
Aquatic weeds and insects both are very much harmful to fish farming ponds as weeds consume almost all nutrients and reduce the amount of oxygen. Their growth should be controlled efficiently so that they cannot create any problem in the pond.
Removing cannibalistic and unwanted fishes:
Removal of cannibalistic and unwanted fishes is very much important step in pond preparation. Shol, gozar, boal, taki, etc. are cannibalistic fish and mola, dhela, chanda, pumpti etc. are unwanted fish.
They can be removed by drying the pond or by using poison in the pond. Rotenone powder is the best option for this purpose.
Conditioning the pond:
Conditioning is done by application of a layer of lime or calcium hydroxide which is spread over the bottom of the pond for two weeks. It is usually applied during or after the pond drying stage. This removes the acidity of the soil, facilitates biogeochemical cycles and prevents unwanted species.
Liming can be done in three different ways:
- By broadcast over a dried pond which includes the dike walls.
- By mixing with water and spraying over the pond and
- By liming the water flowing into the pond.
After 15 days of liming, manuring or fertilization is done in order to facilitate the growth of fish food organisms. Manure can be of organic or chemical nature. The application rate of raw cow dung for stocking pond is 2-3 tonnes/ha. The application rate of poultry manure is 5000 kg/ha.
Use of chemical fertilizer depends upon the concentration of phosphorus and nitrogen in the soil and varies accordingly. The standard combination of NPK is 18:10:4 for freshwater ponds.