"It looks like the damage is greater than before," President Park said while on board the boat off the coastal city of Tongyeong, some 450 kilometers south of Seoul, reports YonhapNewsAgency.
"This keeps happening like an annual event. We need to put together a fundamental solution. We have to pool wisdom together with experts and fishermen to prevent this."
Tongyeong Mayor Kim Dong-jin told Park that the problems are so bad that he even hopes for a typhoon to come and clean up the red tide.
A red tide is a natural phenomenon believed to be caused by a combination of high temperatures, salinity and nutrients. Some experts believe that when these conditions meet low winds and certain rain levels, toxic bacteria, called gymnodinium breve, multiply rapidly and have a red or brown color.
The government has issued red tide alerts for waters off the eastern and southern coasts. Tongyeong is one of the hardest-hit areas in the latest wave that has killed more than 20 million fish in 187 farms in the region, according to officials.