Abstract: Using silver carp and bighead carp to control the excessive phytoplankton growth in eutrophic ecosystem remains controversial, because some authors reported that after stocking additional carps, there is a stimulation of small-celled plankton and an increase in the number and biomass of algae. Many reasons may cause these ecological problems, and the effect of the excretion from the carps cannot be ignored. This paper reviewed the researches on the composition of the excretion from silver carp and bighead carp, the growth and photosynthetic activity of phytoplankton passed through the intestine of silver carp and bighead carp, and the nutrient recycling and contribution in aquiculture system. Because of the complexity of the origin and biotransformation process of the nutrients in aquaculture systems, it’s hard to identify how the excretion nitrogen affects the structure of plankton communities and the transmission process by traditional methods. Therefore, chlorophyll fluorescence system and isotopic technique are suggested to be introduced to study the ecological effect of the excretion from the carps in controlling algal bloom, which would help to understand the mechanisms and feasibility of nontraditional bio-manipulation in cyanobacterial bloom control.

Key words: Rice, Nitrogen application levels, Yield simulation, Optimization, Paddy field