有害有毒赤潮の生物学(12)赤潮の防除対策

摘要

Countermeasures against harmful red tides (especially fish-killing red tides) were reviewed on the laws and techniques of physical, chemical, and biological control. The special law for the conservation of the environ-ment of the Seto Inland Sea has been most effective to regulate the progress of eutrophication by virtue of limitation of effluents of nutrient matters into the Seto Inland Sea, leading to decrease in the occurrence incidents of red tides. As advanced cases for regulation, history of insect pest control was reviewed and the ideas were applied to control of harmful red tides in the sea. Low technologies appears to be most practical and effective to prevent red tide occur-rences when the methods were based on high level knowledge of red tides. As a specific countermeasure, sediment perturbation was proposed to be a strategy for controlling occurrences of harmful red tides such as Chattonella spp. in shallow coastal areas, utilizing diatoms germinated/rejuvenated from the resting stage cells in bottom sediments and resulting growth and consumption of nutrients in water columns.