National park authorities have launched a crackdown on businesses controlled by mafia groups on Koh Samet in Rayong province worth over 100 million baht a month.
The Department of National Parks, Wildlife and Plant Conservation (DNP) is also taking legal action against influential groups on the resort island, said the DNP's Marine National Park Management director Natthaphon Rattanaphan.
The crackdown comes after DNP director-general Thanya Netithammakun signed a transfer order for the Khao Laem Ya-Moo Koh Samet National Park chief, and 79 other officials, in September following a probe into corruption practices.
Earlier, Natural Resources and Environment Minister Gen Surasak Karnjanarat said he wanted order restored to the island.
A panel also was launched to probe two former national park heads and other officials thought to be involved with malpractice.
Mr Natthaphon said an initial inspection found all businesses valued at over 100 million baht a month on Koh Samet were operated by mafia groups, some linked to police officers.
Most businesses were motorcycle, bicycle and jet ski rentals while other businesses involved rentals of speed boats, banana boats, and beach massage services.
According to the investigation, 660 rental motorcycles, over 100 speed boats, more than 10 jet skis and banana boats, 179 beach masseurs, 51 hawkers, 60 taxis, 50 body painters and more than 10 Cambodian fire performers are involved.
Of the speed boats, only one boat was registered legally.
Tourists were required to pay 300 baht per trip for jet skis and banana boats of which 100 baht went to influential figures. Also, each masseur had to pay 500 baht a month to mafia members.
Mr Natthaphon said all businesses now will be regulated. Jet ski, speed boat and banana boat services would be shut down as they could pose a risk to tourist safety.
The authority wants to orient tourism on the island to ecotourism services.
Earlier, the national park reclaimed the beach by ordering operators to remove rental beds and umbrellas.
Mr Natthaphon said the DNP had also discussed with the Rayong provincial governor a plan to close five of of the seven piers on the island after the probe found the piers were exploited by mafia groups.
The gangs would send their members to piers to collect money from tourists. About 60% was handed over to corrupt park officials and the rest to the gangs.
The investigation also found 200,000 baht a month was paid to some Khao Laem Ya-Moo Koh Samet National Park officials.
The act was a form of malpractice as the authorities exploited the country's natural resources to benefit themselves.
Since the transfer of officials, Mr Natthaphon said revenue at the national park had increased, rising four times last month to 4.8 million baht, compared to 1.2 million baht in the same month last year, even though it was low season.
Mr Natthaphon said several operators on the island had called during the crackdown, saying they know influential figures including high-ranking police, military officers and politicians.
He insisted the suppression drive would carry on, pledging to restore Koh Samet as an island for the public.