The pay you get for scuba jobs in St. Maarten will depend on two things. One is the type of scuba job you are doing and the other is who you are working for.
For most of my 15 years on St. Maarten I worked as a scuba instructor. My pay ranged from $1500.00 to $1800.00 US after taxes. Divemasters that worked at the same places made about $1000.00 to 1200.00 US.
There are also some commercial diving and marine construction opportunities on the island. I worked for a year and a half doing marine construction. This paid better than working as an instructor. I took home after taxes a little over $2200.00 US a month.
There are also some good opportunities to create your own dive jobs. These jobs can be anything from working for marinas repairing or placing or moorings and channel markers to working for individual boat owners. The pay for these types of scuba jobs will depend on what you want to charge and want the client is willing to pay.
The thing about places like St. Maarten is there is always work for divers. This is because they are high traffic tropical resort areas.
I hope this information helps. Good luck with your scuba job hunting.