With regard to the red tide in the Seto Inland Sea, number of the red tide had increased year by year until 1976 and reached to 299, partially because the monitoring and dispatch system had been established. After that, the occurrence has decreased. However, about 100 outbreaks of red tide have been observed every year even now. 135 outbreaks were observed in 1997. Weather conditions, such as large precipitation in summer (outbreak season of red tide) and comparatively large number of hit of typhoon, have much influenced the outbreak of red tide. The number and location of red tide occurrence are shown in Figure 5-1 and 5-2, respectively.
The red tide, which occurred in Harima Open Sea in June in 1972, did much damage to the fishing industry. 14 million bred young amberjack died, which deserved of \7.1 billion. The red tide in August in 1977 killed 3.3 million bred young amberjack, which deserved \3 billion. The red tide in June in 1978 killed 2.8 million bred young amberjack, which deserved \3.3 billion. The red tide in August in 1982 killed 0.38 million bred young amberjack, which deserved of 0.8 billion. The red tide in August in 1987 killed 1.4 million bred young amberjack which deserved of \2.4 billion.
Note: after the data by Fisheries Agency
Figure 5-1 Number of Occurrence of Red Tide
Note: after the data by Fisheries Agency (January to December in 1997)
Figure 5-2 Location of Red Tide Occurrence