Harmful algal blooms (HABs) represent a growing threat to aquatic ecosystems, public health, and coastal economies. Biological approaches using grazing organisms remain appealing for HABs mitigation due to their environmentally friendly and sustainable characteristics. Phagotrophic protists, such as ciliates and heterotrophic flagellates, and larger zooplankton, including copepods and cladocerans, are prominent grazers in aquatic food webs, capable of consuming a wide range of phytoplankton and reshaping planktonic community structures. However, few studies have compared these groups to guide the development of practical agents for HABs mitigation. Based on laboratory research and a review of previous studies, this presentation summarizes the advantages and limitations of phagotrophic protists and larger zooplankton, focusing on their grazing capacity, population growth, toxin resistance, and resource efficiency. These findings offer insights into identifying promising candidates for managing HABs of various species and emphasize the significance of micro-grazers in aquatic ecosystems.
 

grazer, bio-mitigation, harmful algal blooms (HABs), ciliate