Magur Fish Farming in india
Magur fish farming is the culture of a type of catfish called Magur, which is native to India and other parts of Asia. Magur fish have high demand and value in the local market because of their therapeutic properties and ability to survive in low-oxygen conditions. However, Magur fish farming is also controversial and banned in some states because of the environmental and health risks posed by an invasive species of Magur called Thai Magur. Thai Magur is a carnivorous fish that can grow up to 5 feet long and can walk on dry land. It can prey on other native fish species and reduce their population. It can also pollute the water with its rotting meat diet. Therefore, only the indigenous Magur species should be cultured in India.
Magur fish farming can be done in two ways: fry rearing and grow out culture. Fry rearing is the process of raising Magur fry from eggs to fingerlings (about 10 cm long) in tanks or hapas. Grow out culture is the process of growing Magur fingerlings to market size (about 100-150 g) in earthen ponds or swamps. Both methods require good water quality, adequate feeding, and health management. Magur fish farming can be a profitable venture if done properly and legally.
Grow out culture of Magur is the process of growing Magur fingerlings to market size (about 100-150 g) in earthen ponds or swamps. It involves the following steps:
- Broodstock maintenance: This is the process of rearing healthy and mature brood fish (male and female) for artificial propagation. The brood fish are reared in earthen ponds or cement tanks with good water quality, adequate feeding, and health management. The brood fish are fed with a mix of groundnut oil cake, rice bran, soybean meal, vitamin and mineral mixtures at about 3-5% of body weight. The sexes can be identified by the shape and color of the anal papilla.
- Artificial propagation: This is the process of inducing spawning and fertilization of eggs artificially by using hormones such as pituitary gland extract or ovaprim. The ripe female and male brood fish are injected with hormones and kept in separate tanks for 6-8 hours. Then they are transferred to a breeding hapa where they spawn and fertilize the eggs. The eggs hatch within 24-36 hours and the newly hatched larvae are collected.
- Fry rearing: This is the process of raising Magur fry from larvae to fingerlings (about 10 cm long) in tanks or hapas. The fry rearing tanks or hapas are prepared by applying lime, organic manure, and mahua oil cake to improve the water quality and plankton production. The fry are fed with boiled chicken egg yolk, tubifex worms, zooplankton, and artificial feed at about 10-15% of body weight. The fry are reared for 40-45 days with 20-30% water exchange and health management .
- Fingerling rearing: This is the process of growing Magur fingerlings from fry to a size of 3-5 g in earthen ponds or swamps. The fingerling rearing ponds or swamps are prepared by applying lime, organic manure, and mahua oil cake to improve the water quality and plankton production. The fingerlings are stocked at a density of 50-100/m2 and fed with artificial feed (30-32% protein) at about 3-5% of body weight. The fingerlings are reared for 2-3 months with 20-30% water exchange and health management .
Some of the advantages and disadvantages of Magur culture
Some of the advantages and disadvantages of Magur culture are:
Advantages:
- Magur is a high value fish that has good taste, texture, and therapeutic value. It can be sold live and fetch a higher price than carps .
- Magur is an air-breathing fish that can survive in poor water quality conditions and low dissolved oxygen levels. It can also tolerate high temperature and salinity variations .
- Magur is a hardy fish that can withstand longer time without water and has an accessory respiratory organ. It can also walk on dry land and migrate to other water bodies .
- Magur is a fast-growing fish that can reach market size (100-150 g) in 10-12 months. It can also be cultured at very high stocking densities (50,000-70,000/ha) in earthen ponds or swamps .
- Magur can be cultured in polyculture with other fish species such as carp, murrel, prawn, etc. It can also utilize the bottom feed resources and reduce the organic load in the pond .
Disadvantages:
- Magur is a carnivorous fish that can prey on other native fish species and reduce their population. It can also pollute the water with its rotting meat diet.
- Magur is an invasive species that can compete with the indigenous fish species for food and space. It can also spread diseases and parasites to other fish species.
- Magur is a cannibalistic fish that can eat its own kind if not fed adequately. It can also cause injuries to other fish species with its sharp teeth and spines .
- Magur is a migratory fish that can escape from the culture ponds or swamps during rainy season. It can also attract predators such as birds and snakes .
- Magur is a sensitive fish that can be affected by bacterial and fungal infections. It can also suffer from stress and mortality due to handling and transportation .
Techniques for breeding, seed production and grow out of Magur
The techniques for breeding, seed production and grow out of Magur are:
- Breeding: Magur is a seasonal breeder that normally spawns during June to August in natural conditions. However, it can be induced to breed throughout the year by using hormones such as pituitary gland extract or ovaprim. The ripe female and male brood fish are injected with hormones and kept in separate tanks for 6-8 hours. Then they are transferred to a breeding hapa where they spawn and fertilize the eggs .
- Seed production: Magur seed production involves two stages: fry rearing and fingerling rearing. Fry rearing is the process of raising Magur fry from eggs to fingerlings (about 10 cm long) in tanks or hapas. The fry rearing tanks or hapas are prepared by applying lime, organic manure, and mahua oil cake to improve the water quality and plankton production. The fry are fed with boiled chicken egg yolk, tubifex worms, zooplankton, and artificial feed at about 10-15% of body weight. The fry are reared for 40-45 days with 20-30% water exchange and health management . Fingerling rearing is the process of growing Magur fingerlings from fry to a size of 3-5 g in earthen ponds or swamps. The fingerling rearing ponds or swamps are prepared by applying lime, organic manure, and mahua oil cake to improve the water quality and plankton production. The fingerlings are stocked at a density of 50-100/m2 and fed with artificial feed (30-32% protein) at about 3-5% of body weight. The fingerlings are reared for 2-3 months with 20-30% water exchange and health management .
- Grow out culture: Grow out culture is the final stage of growing Magur fingerlings to market size (about 100-150 g) in earthen ponds or swamps. The grow out culture ponds or swamps are prepared by applying lime, organic manure, and mahua oil cake to improve the water quality and plankton production. The fingerlings are stocked at a density of 10-15/m2 and fed with artificial feed (30-32% protein) at about 3-5% of body weight. The grow out culture lasts for 10-12 months with 20-30% water exchange and health management .
Magur fish can be harvested by complete dewatering and picking them manually from the culture ponds or swamps. Magur fish can also be cultured in polyculture with other fish species such as carp, murrel, prawn, etc.
Artificial feed used for Magur culture
The artificial feed used for Magur culture is a pelleted feed that contains 30-32% protein and is made of ingredients such as fish meal, groundnut oil cake, rice bran, soybean meal, vitamin and mineral mixtures, etc . The artificial feed is fed to Magur fry, fingerlings, and grow out fish at different rates depending on their body weight and biomass. The artificial feed provides optimum nutrition for Magur growth and reduces the dependence on natural feed resources .
Some examples of artificial feed developed by ICAR-CIFA for Magur culture are:
- CIFAMA: A suitable feed for Magur fry rearing that contains 40% protein and is made of ingredients such as fish meal, soybean meal, groundnut oil cake, rice bran, vitamin and mineral mixtures, etc. It is fed to Magur fry at the rate of 10-15% of body weight.
- Starter-M: A suitable feed for Magur fingerling rearing that contains 35% protein and is made of ingredients such as fish meal, soybean meal, groundnut oil cake, rice bran, vitamin and mineral mixtures, etc. It is fed to Magur fingerlings at the rate of 3-5% of body weight.
- CIFA-Ma: A suitable feed for Magur grow out culture that contains 32% protein and is made of ingredients such as fish meal, soybean meal, groundnut oil cake, rice bran, vitamin and mineral mixtures, etc. It is fed to Magur grow out fish at the rate of 3-5% of body weight.
The artificial feed can also be prepared by the farmers themselves using locally available ingredients and following the recommended protein level and feeding rate .
Feeding methods and devices for Magur culture
The feeding methods and devices for Magur culture are:
- Feeding methods: Magur is a carnivorous fish that requires a high protein diet for its growth and survival. The artificial feed used for Magur culture can be prepared in the form of dough or pellets and fed to Magur fry, fingerlings, and grow out fish at different rates depending on their body weight and biomass. The feeding rate is adjusted based on the monthly sampling and feed consumption rate to avoid feed loss . The artificial feed can also be supplemented with natural feed resources such as live plankton, tubifex worms, zooplankton, trash fish, molluscan meat, etc . The artificial feed can also be mixed with fresh (or frozen) animal blood and viscera to increase its palatability and nutritional value. Magur is fed twice a day, preferably in the morning and evening .
- Feeding devices: Magur is a bottom feeder that prefers to feed in dark and sheltered places. Therefore, the artificial feed can be placed in feeding baskets or trays that are submerged in the pond bottom at different places to avoid intraspecific competition during feeding . The feeding baskets or trays can be made of bamboo, plastic, or metal and should have holes or slits to allow the water circulation and prevent the feed from spoiling . The feeding baskets or trays should be checked regularly and cleaned if necessary . Alternatively, the artificial feed can also be broadcasted manually or mechanically over the pond surface .
Water quality parameters for Magur culture
The water quality parameters for Magur culture are:
- Temperature: Magur is a tropical fish that can tolerate a wide range of temperature from 14°C to 38°C. However, the optimum temperature for Magur growth and survival is 25°C to 30°C . Temperature affects the metabolic rate, oxygen demand, feed intake, and disease resistance of Magur. Temperature also influences the spawning and hatching of Magur eggs .
- Dissolved oxygen: Magur is an air-breathing fish that can survive in low dissolved oxygen levels as low as 0.5 mg/L. However, the optimum dissolved oxygen level for Magur growth and survival is 4 mg/L to 6 mg/L . Dissolved oxygen affects the feed conversion efficiency, growth rate, and stress level of Magur. Dissolved oxygen also influences the microbial activity and nutrient cycling in the pond .
- pH: Magur can tolerate a wide range of pH from 4 to 10. However, the optimum pH for Magur growth and survival is 6.5 to 8.5 . pH affects the availability of nutrients, toxic substances, and pathogens in the pond. pH also influences the skin and gill function, blood chemistry, and enzyme activity of Magur .
- Electrical conductivity: Electrical conductivity (EC) is a measure of the total dissolved solids (TDS) or salinity of water. Magur can tolerate a wide range of EC from 50 µS/cm to 10,000 µS/cm. However, the optimum EC for Magur growth and survival is 500 µS/cm to 2,000 µS/cm . EC affects the osmoregulation, water balance, and ion exchange of Magur. EC also influences the nutrient availability, water clarity, and plankton production in the pond .
- Turbidity: Turbidity is a measure of the suspended solids or cloudiness of water. Magur can tolerate a moderate level of turbidity up to 100 NTU. However, the optimum turbidity for Magur growth and survival is 10 NTU to 40 NTU . Turbidity affects the light penetration, photosynthesis, and dissolved oxygen production in the pond. Turbidity also influences the visibility, feeding behavior, and predator-prey interaction of Magur .
- Nutrients: Nutrients such as nitrogen (N), phosphorus (P), and potassium (K) are essential for the growth and reproduction of Magur and its natural food organisms. However, excessive nutrients can cause eutrophication, algal blooms, oxygen depletion, and water quality deterioration in the pond . The optimum nutrient levels for Magur culture are: N < 0.5 mg/L; P < 0.1 mg/L; K < 10 mg/L .
- Toxic substances: Toxic substances such as ammonia (NH3), nitrite (NO2), hydrogen sulphide (H2S), heavy metals (e.g., copper, zinc, lead), pesticides, herbicides, etc., can cause acute or chronic toxicity, stress, disease, or mortality to Magur and its natural food organisms. Therefore, these substances should be avoided or minimized in the pond water . The maximum permissible levels for some toxic substances for Magur culture are: NH3 < 0.02 mg/L; NO2 < 0.1 mg/L; H2S < 0.002 mg/L; Cu < 0.006 mg/L; Zn < 0.03 mg/L; Pb < 0.005 mg/L .
Yield
The yield per tank of Magur culture depends on several factors such as the size of the tank, the stocking density, the feeding rate, the water quality, the health management, and the culture period. However, based on some reported studies and experiences, the average yield per tank of Magur culture can be estimated as follows:
- Fry rearing: Magur fry can be reared in tanks or hapas with a size of 10 m2 to 20 m2 and a depth of 1 m to 1.5 m. The stocking density can range from 2,000 fry/m2 to 3,000 fry/m2. The feeding rate can range from 10% to 15% of body weight. The water exchange can range from 20% to 30% every alternate day. The culture period can range from 40 days to 45 days. The average yield per tank of Magur fry rearing can range from 8 kg to 12 kg .
- Fingerling rearing: Magur fingerlings can be reared in earthen ponds or swamps with a size of 0.1 ha to 0.2 ha and a depth of 1 m to 1.5 m. The stocking density can range from 50 fingerlings/m2 to 100 fingerlings/m2. The feeding rate can range from 3% to 5% of body weight. The water exchange can range from 20% to 30% every alternate day. The culture period can range from 60 days to 90 days. The average yield per tank of Magur fingerling rearing can range from 150 kg to 300 kg .
- Grow out culture: Magur grow out fish can be cultured in earthen ponds or swamps with a size of 0.5 ha to 1 ha and a depth of 1 m to 1.5 m. The stocking density can range from 10 fish/m2 to 15 fish/m2. The feeding rate can range from 3% to 5% of body weight. The water exchange can range from 20% to 30% every alternate day. The culture period can range from 10 months to 12 months. The average yield per tank of Magur grow out culture can range from 3 tons to 15 tons .
