A Chinese fishing boat captain who stabbed to death a South Korean coastguard in a row over illegal fishing in the Yellow Sea has seen his jail sentence reduced to 23 years. Cheng Dawei , 43, from Suizhong county, Liaoning , was initially jailed for 30 years for killing corporal Lee Cheong-ho, after he boarded his boat in December. Cheng also seriously injured another officer. His initial sentence was delivered in April by a court in Incheon, a port city on South Korea's west coast, but he was retried at the high court in Seoul yesterday, after China refused to accept the first verdict. Liu Liancheng , captain of another boat sailing with Cheng, who had been accused of attacking a patrol guard, also had his five year jail sentence reduced to four years. Cheng and Liu will be fined 20 million South Korean won (HK$137,460) each. Alleged illegal fishing in the Yellow Sea has resulted in several violent clashes between Chinese and South Korean sailers. December's stabbing was the second time Chinese fishermen had killed a South Korean coastguard officer in less than four years. While Chinese fishermen caught in the area are usually released with a fine, Cheng's case sparked outrage in South Korea and prosecutors had sought the death penalty. China's fishing disputes with its neighbours are on the rise. As the world's biggest consumer of seafood, it has overfished most of its offshore waters and so fishermen are driven to nudging the ocean borders of countries, such as Russia, North and South Korea, Japan, the Philippines and even Palau, sometimes intruding into their territory.