Marine reserves that are protected from fishing and pollution with very quickly attract large schools of Snapper and most of the reefs around Phi Phi have many different species of them
That what the governments should do. Fishing area should be in certain location, it should be a distance to the reservation area.
Absolutely correct. The problem in Thailand is the marine parks simply don't have the resources to fight illegal fishing so its an uphill battle for them. The fishing industry is protected however by mafia and major players with government connections.