A quick note. There is a WRSTC standard for Supervised Diver.If you really want to get an apples to apples comparison, use the WRSTC guidelines. All of the major cert agencies follow those minimum standards at this point...
RSTC STANDARD ISO STANDARD ALTERNATIVE ISO TITLE Introductory Scuba Experience No equivalent No equivalent Level One Diver Supervised Diver Open Water Diver Level Two Diver Autonomous Diver Dive Supervisor Level Three Diver Dive Leader Assistant Instructor Level 1 Instructor Scuba Instructor Level 2 Instructor Instructor Trainer No equivalent No equivalent Service Provider
You should also include Enriched Air Nitrox certification: WRSTC standard and ISO 11107:2009
The chart above gives one answer. If you are looking at the nearly universally recognized training standards from WRSTC and ISO, "recreational diving" is 40m max, compressed air or nitrox to 40% only. Outside of instruction, there is only one certification for autonomous divers - Open Water for WRSTC and Autonomous for ISO - and one certification for Nitrox. Everything else depends entirely on individual decisions by agencies or local operators.BSAC now has two Advanced diver grades.
1. Advanced Ocean Diver, and
2. Advanced Diver.
The first takes an Ocean Diver to 30m and teaches mid-water DSMB deployment with some navigation, the second is an individual capable of organising dive trips anywhere from any platform using OC, CCR and/or trimix; they may or may not be an instructor.