The worst sea ice in three decades on China's eastern coast is expected to melt in March, a senior official from the national ocean agency said yesterday.

"So far, about 35 percent of the water in the Bohai Sea has been covered with ice, about 16 percent less than the peak in mid-January," said Lin Shanqing, director of the forecast and disaster relief department of the State Oceanic Administration (SOA).

But transportation departments should pay extreme attention to security during the ice-melting season in late February and early March, during which floating ice will endanger passing ships, he said.

The thick ice has been threatening shipping and the livelihoods of fishermen on the country's eastern coast since late last year and the SOA issued warnings for sea ice on January 13 to avoid any further damage caused by it.

The worst sea ice in 40 years in the Bohai and Yellow seas in early January could cause more than 2.2 billion yuan ($323 million) of economic losses in Shandong province. Oil giant Sinopec has also closed six of its eight drilling rigs in the Shengli oilfield due to the thick ice, Xinhua reported.

Wang Hui, deputy-director of the National Marine Environmental Forecasting Center, told China Daily that the sea ice this winter occurred about one month earlier and has influenced most ocean areas.

But exact economic losses caused by the sea ice are still being studied, Wang said.

Marine disasters in China last year left 95 people dead or missing with a direct economic loss of more than 10 billion yuan, a report on marine disasters last year released by the SOA yesterday showed.

Disasters such as storm surges, extreme waves, sea ice and red tides occurred 132 times, with the number was lower than the past, said Li Haiqing, spokesperson for the SOA.

Guangdong province was also hit by a storm surge eight times last year, with a direct economic loss of nearly 4 billion yuan, the report showed.