Replacement of snow-trout (Schizothorax zarudnyi) by common carp in poly culture

Snow-trout and Chinese carps (silver, big head, grass, and common carps) were cultivated at 3000/ha stocking density from July 2005 to November 2006 at Zahak hatchery in Sistan and Baluchestan Province. Species composition for cultivation was as follows: 65% silver carp, 20% common carp, 5% big head, 10% grass carp, and Snow-trout stocking density was 110 specimens per pond. Cultivation was carried out at the 3 treated ponds and 3 control ponds with 3500 m2. Physical and chemical parameters were determined during cultivation period. Survival rates of species were as follows: 24.55% Snow-trout, and 87.88% all four carp species. The initial average weight of Snow-trout fingerlings was 40 g which during cultivation period obtained average weight of 302.1±14 g. Results show that the difference between final mean weights of Chinese carps in poly culture in comparison with monoculture of them was significant (p<0.05). The average total yields at the poly culture ponds were 1495.8 kg/ha and in control mono culture ponds of Chinese carps was 1681.14 kg/ha. Results showed that the average carp production is more than Snow-trout but grass carp yield in the project's pond was more than control ponds. The total average yield in the poly culture of snow-trout and Chinese carps (Project ponds) was 1312 kg/ha and in the poly culture of just Chinese carp (control ponds) it was 1681 kg/ha. Due to the price of snow-trout in the local market comparing with the price of carp it is recommendable to suggest cultivating of this fish to the fish farmers.