Since there are currently no practical countermeasures for harmful algal blooms (HABs) other than passive measures such as stopping feeding and moving cages, there is an urgent need for effective and environmentally friendly strategies against HABs. Biological control strategies are considered to be more environmentally friendly than physicochemical methods. We propose that the development of seaweed and seagrass beds is effective against the occurrence of HABs through the activities of algicidal bacteria in the biofilm on the surface of seaweeds and seagrasses. As another strategy against HABs, we propose resuspending diatom resting stage cells (which require light for germination) from bottom sediments into the euphotic layer through sediment perturbation, thereby promoting the proliferation of vegetative cells after germination. Nutrients will be quickly consumed by growing diatoms, and HABs of flagellates would be prevented. Chattonella red tides were prevented by bottom sediment perturbation in Tomonoura. Toxic Alexandrium blooms have also been suppressed by bottom sediment perturbation in 2020-2024 in Osaka Bay
Imai et al. (2025) studied this question.