US energy giant ConocoPhillips China (COPC), operator of the Penglai 19-3 oilfield in the Bohai Bay, is fully responsible for two major oil spills that occurred since June last year that caused 1.683 billion yuan ($264.44 million) in ecological damage, according to a report by the State Ocean Administration (SOA).

The severe oil spills have polluted 6,200 square kilometers of water, an area about nine times the size of Singapore.

Some 870 square kilometers were heavily polluted and huge losses in aquatic farming industries of Liaoning and Hebei provinces were caused, the SOA said in an online statement.

The pollution has reduced the marine plankton species and diversity, influencing the structure of biological communities, the report said.

Fish eggs in the area were reduced by about 83 percent last year.

Under a damage compensation agreement signed between the SOA, COPC and China National Offshore Oil Corporation (CNOOC), COPC is to offer 1.09 billion yuan for ecological losses, while CNOOC and COPC paid 480 million yuan and 113 million yuan, respectively, for environmental protection efforts in the country's Bohai Bay.

The compensation to fishermen has been remitted to the government accounts of Hebei and Liaoning provinces, according to the statement. Authorities identified and verified fishermen's losses, and have informed fishermen about compensation standards and measures.

Zhao Zhangyuan, a researcher at the Chinese Academy of Environment Science, told the Global Times that the oil producer deserves such a punishment, the heaviest fine issued by the government in the country.

Considering the long-term impact on the marine environment in the Bohai Bay area, the fine is not above what he assumed the US energy giant's liability would be, the expert said.

"The ecological damage is even more severe than that in the Gulf of Mexico caused by British Petroleum. The government should make much stricter regulations and punishments to force energy companies to prioritize environmental protection in any exploration," Zhao said.

The report also said that the COPC is to give 1 billion yuan to compensate fishermen in Hebei and Liaoning provinces for their losses, according to an agreement signed between the local governments, the Ministry of Agriculture and the two companies.

In addition, the COPC and CNOOC will also take out 100 million yuan and 250 million yuan from the latter's marine environmental fund to replenish natural fishery resources, according to earlier media reports.

At the end of last year, CNOOC filed an application to the Ministry of Civil Affairs for registration of a marine environmental fund with an initial donation of 500 million yuan.

"The fund was not established for compensation but public welfare," said an unnamed spokesman then with the company, adding that fishermen will benefit from the fund.

The Penglai 19-3 oilfield is one of the country's largest offshore oilfields, with daily production of about 160,000 barrels.

The COPC operates the Penglai 19-3 oilfield, in which CNOOC, China's largest offshore oil producer, holds a 51-percent stake while ConocoPhillips holds 49 percent.