Chinese fishermen in northern Hebei Province believe oil particles from a huge spill off the east coast caused a massive death of scallop that they cultivated this season.

More than 160 groups of scallop-raising fishermen have reported to the agricultural bureau in Laoting County that more than half of the scallop cultivated in a shore area of 23 hectares died after greasy oil particles were found along a 25-km beach.

Fishermen said the contamination came from oil spills at the Penglai 19-3 oil field jointly operated by the Houston-based ConocoPhillips' China subsidiary and its Chinese partner China National Offshore Oil Corp. (CNOOC).

China's oceanic authorities ordered the field to halt production on July 13, and revealed the spills had occurred as early as the first half of June.

The State Oceanic Administration concluded this week that oil particles from the spills in Bohai Bay have been found spreading to beaches in Jingtang Port of Hebei and Dongdaihe Bathing Beach in the county of Suizhong in northeastern Liaoning Province.

The beach in Laoting is only five sea miles away from Jingtang Port.

"Some fishermen plan to hire lawyers to sue CNOOC and ConocoPhillips for the contamination-triggered aquatic losses," said Yang Jizhen, head of the Loating Aquaculture Association, adding the losses from scallop death are estimated at 350 million yuan (54 million U.S. dollars).

But he admitted that it was difficult for the fishermen to obtain validate documents showing the oil spill from the Penglai 19-3 field was the direct cause of the death.

"The quality of scallop is mainly determined by the quality of the sea water, and half of young shells I bred this year died and the rest aren't good," said Li Jiafeng, one of the fishermen.

He said there were no red tides or abnormal occurrences other than the oil spill that could be attributed to the massive death of the aquatics.

"Only after we found the oil particles on the beach did we think that the oil contamination may be the killer," he said.

Yang said local fishermen suffered similar losses from an under-sea oil pipeline breach in 2006, and that it prevented the resumption of normal production of local aquatic farming for over two years.

He said fishermen had expected revenue of 340 million yuan from the scallop-farming investment of 170 million yuan this year. However, the ocean contamination could vanish their hopes.

Several government departments in Laoting, including the marine affairs bureau and the environment protection bureau are investigating the oil contamination situation.