You cannot just go lobstering commercially without license, laws are crazy when it comes to that.
We used to spearfish lobster in Sint Maarten. Nothing like going out in my own little tender with my own snorkel or SCUBA gear and coming back a couple hours later with a bag of lobsters. They weren't great or YUUUUGE, but when you've got a dozen, you can have 2 or 3 lobster tails each.