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Сообщение от Lubes
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Ось тобі посилання: http://www.aquacultureassociation.ca...0of%20Japanese
І ось текст:
Culture of Japanese Ornamental Dish Cyprinus carpio var koi in Hardwaters under Tropical Environ.
R. Raghavan*1 and V. Ramadhas2, 1Assistant Professor,Dept. of Fisheries Environment, Fisheries College and Research Institute, Tamil Nadu Veterinary and Animal Sciences University, Tuticorin, India-628 008.2Professor, Dept. of Fisheries Environment, Fisheries College and Research Institute, Tamil Nadu Veterinary and Animal Sciences University, Tuticorin, India-628 008.
Mass production of Japanese koi Cyprinus carpio var koi was undertaken in a freshwater fish pond for twelve months. Water temperature (27.8 – 32.2oC), pH (8.1 – 8.4), dissolved oxygen content (5.43 – 9.74 mg/l), carbonate alkalinity (6.21 – 24.52 ppm), bicarbonate alkalinity (45.92 – 75.34 ppm), concentrations of nitrogenous nutrients (ammonia, nitrite and nitrate) and the availability of phosphate (0.82 – 3.82 mg. at. P/l) did not adversely affect the growth of koi. However, hardness of the water exceeded 300 ppm level and affected the growth. Impact of water hardness on the growth and growth rate of koi was investigated by growing the fish in three different levels of water hardness viz., low water hardness (172.48 ppm ±13.56), moderate water hardness (786.54 ppm ± and high water hardness (1174.54 ppm ± 94.14). The highest mean growth rate of 1.02 mg/g/day was recorded in low water hardness and the moderate and high water hardness recorded the mean growth rate of 0.834 and 0.517 mg/g/day respectively. In all the three different levels of water hardness, the water hardness was observed to exhibit highly significant (P<0.01) positive correlation during the culture period. In the case of high and moderate water hardness highly significant (P<0.01) positive correlation prevailed between carbonate alkalinity and the duration of culture period. The possibilities of introducing koi carp as alternate species for common carp in the composite fish culture practice and a comparative study on the economics of these two species also discussed in detail.
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