Ecological Efficiency of the Mussel Hyriopsis cumingii (Lea, 1852) on Particulate Organic Matter Filtering, Algal Controlling, and Water Quality Regulation

Hyriopsis cumingii plays an important role in aquatic ecosystems and fishery economy due to its potential value for water purification and edibleness. The present study was undertaken to reveal the short- and long-term purifying effects of H. cumingii on pond water. The short-term experiment results showed that total suspended solids, particulate organic carbon, and fatty acid in water were significantly eliminated by H. cumingii, with average percentage of filtering effect respectively reaching 22.19%, 57.48%, and 21.00% in the high-density group. Analogously, H. cumingii could significantly reduce phytoplankton biomass, species number, density, and chlorophyll-a concentration, especially in the control of diatoms, green algae, and cyanobacteria. Besides, electric conductivity also was significantly reduced by H. cumingii and its variation tendency showed a typical density-dependent effect. Similar purification effects were observed in chemical oxygen demand (COD), total nitrogen, and total phosphorus. In the long-term monitoring test, H. cumingii has also shown positive effects on the water transparency and the control to phytoplankton and COD in recirculating aquaculture pond. Overall, H. cumingii showed excellent ecological function, and the mixed breeding density of shellfish in the recirculating aquaculture pond is worth further exploration.