A Philippine court has fined and sentenced 13 Vietnamese poachers to several months in prison after they were caught two years ago trying to flee with 101 critically endangered turtles, a conservationist group said Friday. The World Wide Fund for Nature said the sentences, handed down last week in the southwestern island province of Palawan, could serve as a precedent and a strong warning to poachers from nearby countries who in the past have escaped prison time. In the last decade more than a thousand foreigners – most of them Chinese and Vietnamese – have been arrested and charged with poaching but “sentences have historically proven rare, under fear of damaging international relations with neighboring countries,” WWF said in a statement. The Philippine navy said it nabbed the Vietnamese fishermen in 2008 after firing warning shorts during a 30-minute sea chase as they attempted to scuttle their boat by flooding the holds. The sailors found 101 drowned Hawksbill Turtles – classified as critically endangered – in the vessel's cargo holds. To be classified as critically endangered is the highest risk rating for a living animal, WWF said. The Puerto Princesa Regional Trial Court convicted and sentenced the fishermen to between six and 18 months in prison plus fines. The court ruled that only the fines remain to be served because the poachers have been detained since September 2008. WWF said the 2008 catch proved one of the largest illegal wildlife hauls in the Philippines that year.