I almost want to say hire a security consultant, don't write anything on paper. memorize gps cord nets. leave no info around your house. dirt bags would not hesitate to brake in to look for clues or maps if they do figure out who you are. As a gold miner I feel one of my most important tools is a good 45. I hate to bring a dark cloud to the treasure beach but facts is facts.
Spend time metal detecting beaches the other side of the Island from where your finds have been. If working from a boat do go fishing, but not always over your hot spot. Especially now you have pics, go fishing some place else a few times. Wouldn't be funny to watch someone diving where you went fishing and caught dinner, as long as it was miles from your spot.
Best of luck, stay safe , and trust no one. NO ONE.
My brother and I were best friends I worked hard for free to help him start a new business. Right after he bought his wife a new sports car is when I began to realize three things. 1.the company was making money, 2. WE meant him, and 3.he never intended for us to be in business, together. I, years latter ask him why he thought I spent all that time and money. His answer was " I thought you had nothing better to do." All the verbal agreements he conveniently forgot. Get any and all agreements in writing, no matter how small you think they are.
example Someone wants to come dive with you one day only. Written agreement on who keeps what. What if he comes and is the one who finds the big chest full of gold. If he gets whatever he finds you could be screwed. You do all the work, work on it for years and this one day diver walks away with the biggest part of the loot. Get these kind of things planed out way ahead of time. good luck.