What is a red tide of "Cochlo"？

"Cochlo" Red Tide （The dark color area is red tide）
						What color does a red tide of "Cochlo" have?
						Where does a red tide of "Cochlo" occur ?
						What kind of damage does a red tide of "Cochlo" cause?
						How does a red tide of "Cochlo"expand ?
						What mechanism does a red tide of "Cochlo" occur ?
						What kind of countermeasure do we have against red tides of "Cochlo" ?