Yes you will need a local licence (Valid only for the Azores) and it's totally forbidden targeting , moon fish, manta rays, mero (grouper) dolphins and other similar species.
You have to use of a signalizing float, and on the Azores it is only possible to catch a maximum of 5 fish a day per diver.
It's forbidden the use of breathing assistance gear other then the snorkel.
If you planning on coming contact Paulo Reis at:
bwe@bwexpeditions.com
For more information about the Azores go to:
Azores Tourist Guide - Destinazores
Cheers,
Marco