Failure to pay fee: Preah Sihanouk boats may stop trips
1 December 2017
Twelve of the 16 boat companies that transport tourists to islands off Preah Sihanouk province face the threat of having their licences revoked and being shuttered temporarily by authorities if they fail to pay a marine conservation fee by December 4, according a warning letter.

Phai Bunvannak, Preah Sihanouk provincial deputy governor, on Wednesday issued an announcement saying officials will take action against boat companies that haven’t paid the 8,000 riel (about $2) fee per tourist for the management and preservation of the beaches and islands in the province. The fee requirement was issued in July.

Bunvannak yesterday confirmed that if companies don’t pay up, authorities will “halt [their] activities . . . temporarily to wait for a legal solution”...
http://www.phnompenhpost.com/national/f ... stop-trips

Update:
Sihanoukville boat companies agree to pay fee
6 December 2017
Owners of a dozen large speedboat companies shuttling between mainland Preah Sihanouk province and its islands have agreed to pay a fee to provincial authorities for every passenger, but small boat owners are still trying to negotiate a lower cost.

Ol Va, owner of On The Rocks Tours, said his and the 11 other major speedboat companies that had not been paying the conservation fees agreed during negotiations yesterday to pay $2 for every round trip ticket to Koh Rong and Koh Rong Sanloem. The fee is supposed to go towards preservation and biodiversity conservation projects, according to Phai Bunvannak, Preah Sihanouk provincial deputy governor.

Bunvannak issued a statement in late November threatening to suspend speedboat services temporarily if the companies did not agree to pay by Monday. However, owners of small boat companies carrying up to 15 passengers are still seeking a lower fee, Va said.

Va said these boats generally travel to closer islands and, unlike the larger boats, negotiate prices with their customers. He added he would consider their request.
http://www.phnompenhpost.com/national/s ... ee-pay-fee

$20 for a ticket to the islands is what most of the stoned backpackers will pay for three nights in a 'Fan Room' at Otres.