Abstract
A red tide occurred over a small portion of they bay in the 1980s. And a red tide has been transported up the South, West and East seas since the middle of the 1990s. The most common cause of a red tide was flagellate algae since the 1990s. In 1995, accounted for 95% of the total occurrence of the red tide. The harmful red tide was caused by the Cochlodinium that affected fishery operations in 1993 and 1994. Furthermore, it spread to the southern part of the East sea. In late August, 1995, a Cochlodinium red tide occurred frequently in outside of the Narodo coast, and then moved to the western part of the South sea. It lasted a month and then went away at the beginning of October. In August, 1998, It first appeared off the Narodo coast, and then spread repeatedly to the West and East coasts until the 15 of September. By carefully studying water quality, three characteristics of a Cochodinium red tide were identified about a month before the appearance of the red tide, there by effectively preventing a loss to the fishing industry. As a result, the water temperature was high (about 24°C) at the beginning. The concentrations of dissolved nitrate and phosphate were low, especially in the Narodo. However, conditions were favourable for the multiplication of Cochlodinium polykrikoides. With regards to phytoplankton, the amount of flagellate algae went up rapidly in the middle of August. By the latter half of the month, it accounted for 98% of the plant life. With the increase of nitrate and phosphate, the tablated water temperature reached 24-26°C. Cochlodinium red tide occurred in the Narodo coast several days later.
