Selection of Pond:
The main criteria to be kept in mind while selecting the ponds that the soil should be water retentive, adequate supply of water is assured and that the pond is not in a flood prone area.
Pond Management plays a very important role in fish farming before and after the stocking of fish seed. Various measures that are required to be undertaken in pre and post stocking practices are tabulated below :
Prestocking: In case of new ponds, prestocking operations starts with liming and filling of the pond with water. However, the first step for existing pond requiring development deals with clearing the pond of unwanted weeds and fisheseither by manual, mechanical or chemical means. Different methods are employed for this.
- Removal of weeds by Manual/Mechanical or through Chemical means.
- Removal of unwanted and predatory fishes and other animals by repeated netting or using mahua oil cake @ 2500 kg/ha metre or by sun drying the pond bed.
- Liming – The tanks which are acidic in nature are less productive than alkaline ponds. Lime is used to bring the pH to the desired level.
Fertilisation of the pond is an important means of intensifying fish culture by increasing the natural productivity of the pond. The fertilisation schedule has to be prepared after studying the quality of the pond soil. A combination of both Organic and Inorganic fertilisers may be used for best results. The fertiliser programme has to be suitably modified depending on the growth of the fish, available food reserve in the pond, physico chemical conditions of the pond and climatic conditions.
The pond will be ready for stocking after 15 days of application of fertilisers. Fish fingerlings of 10 cm size (approx) should be used for stocking @ 5000 nos. per hectare. However if fingerlings of smaller size are used, suitable allowance may be made accounting for mortality.Depending on availability of seed and market condition, stocking can be of 3, 4 or 6 species combination
a) Supplementary feeding:
Fishes need much more food than what is available naturally in the pond. Fishes can be fed with a mixture of bran and oilcake in equal quantities daily. The feed should be placed on a bamboo tray and lowered to the pond bottom or it can be sprayed at the corners.
i) Organic manuring may be done in monthly instalments @ 1000 kg/ha.
ii) Inorganic fertilisation may be done at monthly intervals alternating with organic manuring.
Harvesting is generally done at the end of 1 st year, when the fishes attain average weight of 750 gms to 1.25 kg. A production of 4 to 5 tons/ha can be obtained in a year. Harvesting is done by partial dewatering and repeated netting.
Vertical expansion of fish culture:
A number of measures are now being employed by the entrepreneurs to increase the per hectare production of fish. Important measures adopted are stocking of Yearlings by stunning the growth of fish seed during first year, heavy stocking and multiple harvesting after the fishes attain a size of 500 gms. It is possible to increase the per hectare production of fish to 7 to 10 tonnes per ha per year by employing different methods as indicated above.