Greg it seems you got the last part of what I said but given the title of this thread, you missed a couple crucial points :lol:
Australia does not coral farm, it's all wild caught.
While PNG has some pilot coral farms running, they are not shipping so the question is moot about how they deal with farming it. There is no wild coral being shipped from PNG either.
My understanding:
Both PNG and Australia work on TAC (I miss typed that on the other thread) Total Allowed Catch. They run transects, count fish, and something like 1% is allowed to be taken. These transects are continually run and the TAC quotas are subject to change. The collectors report all their catches and where they came from. Once quotas are reached, no more can be collected or shipped. In Australia they even GPS track the boats and the divers are only allowed in certain areas. They figure out how much coral there is, then set a very small quota in terms of what is there, and even that is reached. PNG is set up a little different due to how the government structure is (Government, tribes, etc) but it's still basically the same (minus the GPS tracking part).
That of course is the simple answer, I don;t have time to really get into it.