Effects of biocontrol with an atyid shrimp (Caridina denticulata) and a bagrid catfish (Pseudobagrus fulvidraco) on toxic cyanobacteria bloom (Microcystis aeruginosa) in a eutrophic agricultural reservoir

Abstract

The biocontrol effects of Caridina denticulata, an atyid shrimp, on toxic cyanobacterial bloom (Microcystis aeruginosa) were evaluated in a mesocosm study with stable isotope tracers (C-13 and N-15) in a eutrophic agricultural reservoir. The accumulated assimilation (at.%) of M. aeruginosa into C. denticulata was increased, causing a significant reduction in the concentration of Chlorophyll-a. The ingestion rate of M. aeruginosa by C. denticulata was influenced by predation pressure exerted by bagrid catfish Pseudobagrus fulvidraco and was dependent on biomass ratio. C. denticulata affected zooplankton density, species composition, and ingestion rate, demonstrating that the number of small-sized cladocerans (Bosmina coregoni and Bosmina longispina) increased because they grazed M. aeruginosa for a food source. This study suggests that C. denticulata and P. fulvidraco can be feasible material to control a nuisance M. aeruginosa bloom in eutrophic agricultural reservoir.