COMPARATIVE STUDY ON CHANGES IN PHYTOPLANKTON COMMUNITIES UNDER LOTUS-FISH CO-CULTURE AND CONVENTIONAL POND AQUACULTURE MODELS

To compare the variation patterns of phytoplankton communities and their relationship with environmental factors under the lotus-fish co-culture and conventional pond culture modes, the experiment selected lotus-fish co-culture ponds and conventional culture ponds in Shuangfeng County for comparative research. Through monitoring water quality and phytoplankton in spring, summer, and autumn, the correlations between changes in phytoplankton community structure and water quality factors were analyzed. (1) The concentrations of ${\rm{NO}}^-_3 $-N, TP, TN, and pH in the lotus-fish co-culture group were significantly lower than those in the conventional aquaculture group (PNavicula,Scenedesmus, and Merismopedia, respectively, all of which were enriched in the conventional aquaculture group. (4) RDA analysis indicated that algal density in the conventional aquaculture group was mainly driven by ${\rm{NO}}^-_3 $-N, TP, and pH, with biomass showing a significant positive correlation with ${\rm{NO}}^-_3 $-N (PP<0.05). Compared with conventional aquaculture, the lotus-fish co-culture model effectively reduce the risk of eutrophication in aquaculture water, promote phytoplankton species diversity, and inhibit cyanobacteria dominance. This study provides a reference for the scientific management of lotus-fish ecological aquaculture.