Malaysian authorities said they seized roughly one metric ton of fish along with 350kg of endangered sea cucumbers.
Among the 28 crewmembers, 10 were additionally charged with suspicion of smuggling of the protected sea cucumbers.
In addition, one of the Vietnamese fishermen, Tran Van Phuong, 55, died from unknown causes after receiving emergency medical treatment.
The boats with Malaysian registration codes, One United 9 and One United 14 have been seized and taken to Pulau Melayu.
