By Nguyen Quy  September 25, 2018 | 09:50 am GMT+7 Philippine authorities have seized a Vietnamese fishing boat and detained its five-member crew for fishing illegally in their country’s territorial waters. The vessel was intercepted by the Philippine Coast Guard Wednesday off Palawan, an archipelago on the western border of the Philippines, GMA News reported Monday. They seized one ton of yellow fin tuna worth 200,000 pesos ($3,700) and a tiger shark weighing 50 kilograms, local authorities said. The crew allegedly failed to furnish a permit for fishing in Philippine waters. The news site quoted the Coast Guard as saying they “had a hard time chasing the fishermen.” In May this year 20 Vietnamese fishermen had been detained off Mangsee Island in the Philippines with more than 50 pieces of sharks and rays they had chopped up, the Star Online reported. Two months before that 14 Vietnamese fishermen had been arrested off Paluan, a municipality in the central province of Occidental Mindoro, the Malina Times quoted local authorities as saying. Hundreds of Vietnamese fishermen have been caught illegally fishing in foreign waters in recent years. Vietnamese authorities are trying to raise awareness of maritime boundaries and international maritime laws, and carry out regular patrols to prevent potential violations.