If it is Morgans Bay just off East London, then you will be in the middle of a reserve - no fishing off a boat / Jet ski unfortunately - you will have to make a short trip thru to the Kei river to launch through there - I have a few spots there if you are keen - let me know and I will drop you a PM. Shot
Ja, you have to launch out of Kei Mouth. You have to go north of kei mouth as south is the reserve. You will need to contact Kei mouth ski boat club to find out requirements for launching.