Thanks all for your replies and greetings. Here in the Davao channel it gets as deep as 90ft. You have to go out on the backside of Samal to get the 150ft and be in Saranggani to get the 250ft. I still don't do well beyond 40ft My ears sting too badly.
There are many Ilonggo and other Bisayans here in town, but according to the Sama, no one goes much deeper than 50ft except for the Sama.
I don't know the Ilonggo for oyster, but the Sinama is tipay.