Indian Major Carps And Chinese Carps Fish Farming Complete Guide A to Z
- Types of Commercial Carps
- Caps polyculture
- Preparations of pre-storage ponds
- Stocking of ponds
- Management of post-stocking ponds
Types of commercial carps
Tents have been the pillar of cultural practice in India and are the three main Indian tents, namely, catla, rohu, and mrigal, along with three other exotic tents, namely the silver carp, the herbivorous carp and the common carp that contribute more than 85% of aquaculture. Country production
Technological interventions during the last three decades have led to an increase the average levels of national production in ponds and tanks from approximately 600 kg/ha to more than 2,000 kg/ha. Several farmers and entrepreneurs are achieving higher production levels of 6-8 tons/ha/year in states such as Andhra Pradesh, West Bengal, Punjab, and Haryana. Several combinations of farming practices have been developed in the country to adapt to fish species, water resources, fertilizer availability, food resources, etc. and also the investment potential of farmers. It has been shown that carp cultivation is highly compatible with other agricultural practices and also has a high potential for recycling organic waste.
Carp polyculture in India has been using a large amount of organic waste, such as manure or poultry droppings, and production levels of 1-3 tons/ha/year can be obtained with the application of organic and inorganic fertilizers alone The provision of food significantly improves fish production and production levels of 4-8 t / ha/year are obtained using a judicious combination of both food and fertilizers.
The practice packages, as developed in the research institute, have been adopted in ponds ranging from 0.04-10.0 ha in area and 1-4 m in depth in different regions of the country, resulting in variable production rates. While small and shallow stagnant ponds have several inherent problems, which negatively affect the growth of fish, large and deep ponds have their own management problems. Ponds 0.4-1.0 ha in size with a water depth of 2-3 m are considered the best for better handling. Management practices in carp polyculture involve environmental and biological manipulations, which can be broadly classified as pre-storage, storage, and post-storage operations.
Preparations of pre-storage ponds
The preparation of the ponds implies making the ponds free of weeds and predators and generating adequate natural foods to guarantee high survival rates and good growth and, therefore, yields. The control of aquatic weeds, the elimination of unwanted biota and the improvement of soil and water quality are the important aspects related to this management phase. Details on the control of predatory fish and weeds have been discussed in nursery management.
Stockin of ponds
The ponds are stored with seeds of the appropriate size after acclimatizing to the new habitat when ready after fertilization. Both the size and density of the fish are important to achieve high yields. Fry over 100 mm in size is recommended for planting in culture ponds. The storage of smaller fish can cause higher mortality and slow growth during the first months. In intensive polyculture ponds, a size of 50-100 g is preferred for planting to achieve greater survival of more than 90% and better growth. In general, a density of 5,000 fries is maintained as a standard storage rate per ha for carp polyculture for a production target of 3-5 t / ha/year. Load densities of 8,000-10,000 fry/ha have been used for production levels of 5-8 t / ha/year. Fish production levels higher than 10-15 t / ha/year are reached by resorting to the population at a density of 15,000-25,000 / ha. In carp polyculture, the proportion of species is maintained to minimize interspecific and intraspecific competition for food available at various levels and trophic areas in a pond. Two or more species that occupy different niches could be used in a pond to exploit the food available in several areas. While it has been shown that a combination of six species, namely catla, silver carp, rohu, herbivorous carp, mrigal, and common carp, is the ideal combination for carp cultivation in India, the combination of species is largely decided measured by seed availability and market demand. Of these catla and silver carp are surface feeders, rohu is a column feeder, grass carp is a macro-vegetation feeder, and mrigal and common carp are bottom feeders. A proportion of 30-40% of surface feeders (silver carp and catla), 30-35% of medium water feeders (rohu and grass carp) and 30-40% of bottom feeders (common and mrigal carp) are They commonly adopt depending on the productivity of the pond.
Management of post-storage ponds
Fertilization: the ponds are classified into three groups according to the nutrient levels of the soil substrate. Fertilization measures for carp production ponds are recommended as follows. While 20-25% of the total amount of organic fertilizers is applied as a basal dose, a fortnight before storage, the remaining amount is applied in equal installments every two months. Other commonly used organic fertilizers include poultry litter, pig manure, duck droppings, domestic sewage, etc., depending on availability. Azolla, a nitrogen-fixing fern has been standardized as a biofertilizer for aquaculture at an application rate of 40 t / ha/year, demonstrating the complete complement of nutrients necessary for intensive carp cultivation (100 kg of nitrogen, 25 kg of phosphorus, 90, kg potassium and 1,500 kg of organic matter). The debris resulting from the decomposition of the material applied in the ponds serves as a trophic component of carp and prawns. Bioprocess organic manure, the biogas suspension, has been standardized as manure in carp culture, at application rates of 30-45 t / ha/year, with different advantages in terms of lower oxygen consumption and faster rates of nutrient release.
Supplementary feeding: supplementary feeding in the carp polyculture is generally limited to the mixture of peanut/mustard oil cake and rice bran. With the shift towards intensive fish farming, other ingredients from animal and vegetable protein sources are being incorporated. To keep these components together in the feed, granulation is performed, which in turn helps the stability of the water and the reduction of waste. Grass tents are fed with preferred aquatic vegetation (Hydrilla, Najas, Ceratophyllum, duckweeds, etc.) kept in enclosures in selected corners of the pond. You can also use marginal vegetation, pastures and other fodder, banana leaves, and plant debris.
In terms of food dispensing, food mixtures are provided in the form of dough in trays or jute bags hung at different locations in the pond. It is recommended to feed preferably twice a day. Quantitative food requirements are important since insufficient food depresses growth while overfeeding results in food waste. The feed is made at 5% of the initial biomass of the storage material during the first month and more at a variable scale of 3-1% in the following months, depending on the estimated fish biomass at monthly intervals.
Aeration and water exchange: aeration can be used mechanically to increase the concentration of dissolved oxygen in ponds, especially required in intensive crops with higher population density. Paddlewheel aerators, vacuum aerators, and submersible pond aerators are the common aerators used. 4 to 6 aerators/ha of water area is required to meet the demand for dissolved oxygen in intensive aquaculture.
Water exchange is another important activity, considered crucial in intensive aquaculture. Due to the continuous accumulation of metabolites and the unused food in decomposition, water quality deteriorates, which leads to the slow growth of fish species and, often, disease outbreak. Therefore, it is necessary to replace a certain amount of water at regular intervals, especially during the later part of the cultivation period in case of intensive cultivation practices.
Health management: Before planting, a 3-5% potassium permanganate bath should be given for 15 seconds. The incidence of the disease is quite common in high population densities. Although mortality is rarely observed in well-managed ponds, fish growth is severely affected due to parasitic infection that must be treated.
The fish collection is usually done after a cultivation period of 10 months to a year. However, fish that reach marketable size can be harvested periodically to reduce the density pressure in the pond and, therefore, provide enough space for the growth of other fish.