بررسي پرورش ماهي كلمه (Rutilus rutilus caspicus) در استخرهاي خاكي با تراكم هاي مختلف در آب شيرين

Study of cultivation of fingerling of Roach (Rutilus rutilus caspicus) in freshwater earthern ponds with different density

In this study monoculture of roach (Rurilus rutilus caspicus) in freshwater with 3 stocking densities as 10000, 15000, and 20000 specimens per hectare with 3 replications were carried out from the beginning of May till October 2009. Fingerlings from the Sijoval cultivation Center were stocked in a pond for wintering and after preparation of rearing ponds in second year were introduced to the pond. Fingerlings were fed by concentrated food being is given to white fish for feeding (SKF) up to 30g in weight for fingerlings. Feeding calculation based on percentage of body weight varied from 5 to 15 % of body weight. Moreover, appetite of fish also considered for feeding the fingerlings. Average weight (±SD) and length in the first year from hatching time up to the end of rearing period were 5.55±1.58g and 8.57±1.0cm. Results indicated that in the second year and in the different stocking densities the average (±SD) weight and length at the end of cultivation period with minimum treatment were 56.68±16.5g and 16.79±1.21cm respectively. In maximum stocking density the mean average (±SD) length was 16.74±1.23cm and mean average (±SD) weight was 55.33±16.5. Average daily growth in freshwater treatment from the minimum to the maximum stocking density was 0.22, 0.26, and 0.23, respectively. FCR in the freshwater treatment from the minimum to the maximum stocking density was 4.4, 4.46, and 4.4, respectively. Average condition factor in freshwater was from 2.41 in the second treatment to 2.69 in the first treatment and 2.56 in the third treatment. Survival rate in the freshwater treatment from the minimum to the maximum stocking density was 85.41 and 82.21.