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5.2.1. The management of rearing ponds
Unit 5 - Fish seed rearing techniques
5.2.1. The management of rearing ponds
(i) removal of weeds by manual/mechanical method
(ii) eradication of predatory and weed fishes by netting and/or poisoning
(iii) manuring with organic and inorganic fertilizers,
(iv) stocking with carp fry in suitable combinations and ratios,
(v) supplementary feeding and
(vi) harvesting.
- The experiments conducted (during 1965-1967) at Pond Culture Division of CIFRI on rearing of carp fry to fingerling stage in various combinations of IMC and exotic carps, showed average survival of 76.6% (range 53.5 to 97.4%).
- The species combination consists of catla, rohu, mrigal and common carp; silver carp and grass carp; silver carp, grass carp and common carp.
- While the rate of stocking varied between 62,500 and 1,25,000 fry/ha, the number of fingerlings harvested ranges between 33,425 and 95,900/ha.
The production values were in the range of 1,505-3,486 kg/ha (av. 2,204 kg/ha) per 3 months. - The CIFRI later conducted 6-month rearing experiments during 1967-1971 and obtained survival rates of 62.1- 98.0% (av. 78.2%) and gross production values 755-2,462 kg (av. 1,712 kg/ha/6 months).
- In these experiments, fry of grass carp, silver carp and common carp were stocked at 0.1-0.25 million/ha in the ratio of 4:3:3.
- The survival of silver carp was 99%, while that of grass carp was 80-98%. Zooplankton is the most preferred food of catla fry.
- The fry of rohu and mrigal accept other feeds, with silk worm pupae resulting in better growth and survival than other feeds such as mustard/groundnut oil cake/rice bran/wheat bran/soybean/prawn waste.
- A recirculatory system was developed at CIFRI, Barrackpore for carp fry rearing wherein ponds arranged in series were supplied with water passed through a biological filter by means of a pump.
- Advanced fry of catla (35mm/2.2g) and rohu (45mm/2.9g) recorded high survival of 84.4 and 96.6% and a growth of 90mm (7.0g) and 117mm (14.7g), respectively, in 32 days.
Last modified: Tuesday, 14 June 2011, 10:06 AM