[Opinion] An Effective Red Tide Prevention Urgently Needed

The red tide, which was limited to the Masan area during the 1970s when industrialization began, is now spreading across the nation`s coasts. The 1995 red tide spread through the Eastern Seacoast and rose up to Kangreung, causing trouble from the summer until October. A minute red tide organism, about 30 micrometers in size, called Chochlodinium swept across the Kujaedo sea area, which is considered pure, moving over Masan, Pusan, and even reaching Pohang, Uljin, and the Eastern Sea.

The chocolate colored flagella of Chochlodinium spread out like oil, covering coastal farms and causing damages up to 800 million won. This year, the Chochlodinium red tide has begun to spread again, starting in the Tongyoung area and reportedly reaching Ulsan and Pohang shores.

A red tide is caused by the proliferation of a yellow and dark red colored organism called `planktons`. Hundreds of these micrometer sized minute planktons constitute the starting point for the ocean food chain. These minute organisms use nitrogen and phosphorus in the waters to turn the sunlight into organic matter. Other organisms that feed on it form a chain leading up to various fish. Ocean life, therefore, requires that planktons remain in the water. The red tide problem begins when too much plankton simultaneously resides in the water. The Chochlodinium, which is causing the red tide this time, may be only 30 micrometers large, but it splits almost every day and is increasing in such exponential numbers that it is changing the color of the water.

Reported damages in sea farms include ruined soft shell clams, yellow tail, rock fish, file fish, and perch. The main reason for this is usually the red tide organisms blocking the fish gills. When the fish draw in water through the gills, it draws in thousands of red tide organisms along with it, which blocks the gills. Moreover, the poison from the organisms paralyze the fish`s lungs. Consequently, sea farms always suffer huge damages whenever a red tide occurs.

In the Southern Kyongsang coast, around 1400 fishermen and government officials mobilized 600 fishing boats and spread yellow soil in order to prevent the red tide from entering the farms. Yellow soil was first used in the early 1980s in the southern region of Kyushu, Kagushima in Japan and started being used in Korea in 1996. It is an effective method for eliminating red tides. When the yellow soil is spread, colloid particles in the yellow soil absorb the red tide organisms and pull them toward the bottom of the ocean, usually eliminating 80 – 90 percent of the red tide. But yellow soil is only one emergency measure for preventing the red tide from entering the coastal farms and does not constitute a foundational method for eliminating it. The fundamental cause of red tides must be treated in order to reduce them, and this requires decreasing the number of nitrogen and phosphorus in the water that feeds the red tide organisms.

The government proposes two methods for preventing red tides, restrictions on the influx of land pollutants in the sea and reclamation of the seashore. But neither of these restrictions is being faithfully observed. This summer`s red tide occurred after a flood and came in after the rain and all sorts of land pollutants flowed into the sea. The nitrogen and phosphorus extracted from the sewage, combined with the rising water temperature and strong sunlight, made it possible for red tide organisms to flourish. As the government prevention measure prescribes, the influx of pollutants from the land has to decrease but this requires too large a budget.

After the 1995 red tide, the money invested in the five-year pollution prevention plan amounts to about 5 billion won. Most of the money was used to install new sewage systems but this did not reduce the red tides. The priority should be to invest the money in sewage systems in the surrounding cities along the South Seacoast and installing automatic pollution regulators in the coastal farms. Yet, only 900 million won, 2 percent of the 5 billion, was invested in the coastal farm purification project. The second method of restricting reclamation by draining of seashores, which provide a natural means of purification, was unsuccessful. When a ton of money is being invested in the large-scale seashore reclamation, it is hard discuss the seriousness of the red tide problem. For the sake of the fishermen who are suffering from the damages done by the red tide to their coastal farms, the central government must take special measures at this time.

Ko Chul Hwan (Professor of Marine Sciences, Seoul National University)