Feasibility study on common carp (Cyprinus carpio Linnaeus 1758) culture in fresh water earthen ponds of in Golestan Province

In order to rearing and introduction of wild common carp in Golestan province, the fish was reared till grow out stage under mono-culture condition. Fish weighing 50-40 gram with density of 1400 specimens were stocked in three earthen ponds. They were fed on natural production as well as specific feed for common carp based on 5-10% of biomass twice a day. Water oxygen, pH, turbidity, temperature were recorded biweekly during the experiment. Sampling was performed for biometry and calculation of average daily growth and weight gain. The results showed significant growth of the fish and in 6.5 months, the fish reached from initial weight 41.46 gr to an average of 712.49±0.01gr in November of the same year. Also at the end of the study the average daily growth was 3.44, FCR was 2.03, condition factor was 1.06 and survival of 81.83 percent. Overall, the results indicates that common carp can acclimate to warm months of year. Obviously the tropical climate of Golestan province can be effective in improving the growth of carp and this species can be considered as a new culture species for poly culture with Chines cyprinidae.