FAMILY: Cyprinidae
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NAME: Catla catla - Catla |
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Data provided courtesy of Aquaculture/Fisheries Center, University of Arkansas at Pine Bluff - (Dr. Peter Perschbacher) |
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Native from India, this species belong to the so-called group of Indian major carps. It is widely cultured in the plains of the Ganges river system, northern India. HABITS: Catla is considered to be a surface and column feeder. Larvae and young fry feed on planktonic unicellular algae. After reaching a length of about 2 cm, the fry start feeding on zooplanktonic organisms, showing a preference for protozoans and crustaceans. The adults feed on different types of algae, planktonic protozoa, rotifers, crustaceans, mollusks, and decayed macrovegetation. They show a specific preference for planktonic organisms. SPAWNING: A considerable proportion of the fry and fingerlings is raised from eggs and larvae collected from natural spawning grounds in rivers. Some are also bred in special "bundh" type ponds. Induced breeding by hypophysation is now increasingly used in India. For successful hypophysation, an adequate stock of selected brood fish is reared with special care for a period of 4-5 months before spawning. The selected broodfish are generally two to three years old and 2-4 kg in weight. They are stocked at the rate of 1000-2000 kg/ha. Induced breeding is normally carried out at the onset of the monsoons, when there is an accumulation of rainwater in the ponds and the water temperature has somewhat decreased. The dosage of pituitary gland extract to be administered depends on the stage of maturity of the fish and environmental conditions such as rain and water temperature. A priming dose of 1-2 mg per kg of broodfish, followed by a resolving dose of 6-8 mg per kg 6 hours later, is suggested. After the first injection, the broodfish are released in breeding hapas in the proportion of one male to two females. Breeding normally takes place within 3-6 hours after the second and final injection. Stripping is not required. The water-hardened eggs are hatched in hatching hapas. At an optimum water temperature of 26-31° C, the hatching time is 16-18 hours and the hatchlings fall into the outer hapa. The larvae can be reared in the outer hapa for two to three days, after which they should be removed to nursery ponds for further rearing. GROWTH: In stocking production ponds, allowance is usually made for an annual mortality of 30% or more. Very large fish bring poor prices, so catla are seldom left in growing ponds longer than three years. Most fish are sold after the first year, at which time catla have attained a weight of 900 to 4100 g. In very fertile waters, comparable weights may be reached in as little as 6 to 8 months. USES: Catla are often grown in polyculture with the other major Indian carps (rohu, mrigal, and calbasu), though their ecological niches are by no means as distinct and well defined as those of the Chinese carps. Certain of the Chinese carps have been experimentally included in Indian carp polyculture systems and in the future further combinations of Indian carps, Chinese carps, and other fish may be expected in both experimental and practical culture. CULTURE: An ideal stock pond should be 0.2-2.0 ha in area, 1.5-2.5 m deep, rectangular and 20-30 m wide to facilitate netting operations. A convenient source of water for stock ponds is a well or an underground spring. Preparation of ponds before stocking comprises clearing the water of its excess micro- and macro-vegetation, eradication of predatory and unwanted fish and other organisms, manuring and fertilizing with organic manures and inorganic fertilizers. Important post-stocking and stock pond operations cover maintaining the productivity of the ponds through sustained fertilization and feeding the fish. REFERENCES:
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