Red tides have been witnessed in Kagoshima Bay since early March.
Since it has also been confirmed that the sea surface glows blue, it is believed to be caused by ``Yakouchu'', and experts say, ``Since it is non-toxic and has little impact on the fishery, I would like you to leave it to nature and watch over it.''
On March 10, red tide was confirmed on the surface of the sea in a video of Waterfront Park taken from the roof of NHK.
On the night of the same day and the next day, it was confirmed that the surroundings of the Sakurajima Ferry were shining blue.
According to Masayuki Okunishi, Associate Professor of the Faculty of Fisheries, Kagoshima University, who is familiar with red tides, this red tide is caused by plankton with a diameter of about 1 mm called "Yakouchu".
"Yakouchu" has the property of emitting blue light when stimulated, so blue light has been confirmed around ships sailing at night and fishing rods.
In Kagoshima Bay, it grows in large numbers from late February to early May when the water temperature rises, and when it gathers near the quay due to wind and waves, it looks red.
In August of last year, another plankton caused a red tide in the Yatsushiro Sea, killing around 30,000 farmed yellowtail and red sea bream in Nagashima. This means that there is little impact on
Associate Professor Okunishi said, ``It's an annual phenomenon, and when you see 'Yakouchu,' you feel spring.