Cyanobacteria and Hypophthalmichthys molitrix relationship in polyculture pond in semi-arid climate
The carp pond in semi-arid climate showed an excessive developpment of Cyanobacteria in summer. The high diminution of silver carp specific growth rate was probably depending on the presence of this phytoplanktonic group and a part of energy was used for the fabrication of gametes. The specific growth rate in the end of work period was - 0.38%/j. The N/P ratio could not be used as indicator of algae composition. Nitrogenous fertilizers applied many times, high concentration of dissolved oxygen and presence of silver carp have not limited the proliferation of Cyanobacteria in ponds. The only mecanic agitation of water was the solution to decrease them.