Summary Water, nutrients, used farmland zone, and energy are the most important aspects of the ecological sustainability of aquaculture farms. With regard to water, both necessary quantity and quality are important. An equally important goal in all systems is to reduce the amount of water needed in order not to put additional pressure on the natural ecosystem. An equally important objective is to reduce waste water and optimize treatment discharges because, in most cases, aquaculture discharges contain many nutrients that could contaminate natural systems. Traditional cyprinids fishponds only need water to replace the evaporated or infiltrated one; leakage is reduced until harvest. Under these conditions the control of microscopic algae blooms is particularly important. Efficient use of the necessary nutrients is also essential for ecological sustainability. The first step is to reduce food losses through an advanced feed system and by selecting the right feed. Using polyculture technologies can increase the efficiency of nutrients due to various ecological niches of fish species. Thus, in the experiments necessary for the development of an eco-efficient fish species breeding technology, three experimental variants were applied, besides the witness one, to the application of conventional technology, and the use of the growth in polyculture of the Carp species, Silver carp and Bighead. During the vegetative period of 2016 and 2017, the dynamics and structure of phytoplankton and zooplankton were monitored in the four growth experimental pools. The results showed that the phytoplankton structure was dominated by chlorophylls and diatoms, which did not pose problems in terms of the algae bloom phenomenon, algal densities being small. In the semiintensive growth system practiced in pools and ponds, which has as a technological principle the intensification of production on the basis of stimulation of natural fishery production and supplementary feeding, the carp benefits from the stimulation of the zoobenthos development, the silver carp - consumption of the phytoplankton and the bighead - zooplankton consumption .

carp, polyculture, algae bloom , sustainable development.

environmental engineering

Presentation: poster