Fish spotting can be a tough biz to break into. This is because when a boat decides to take you on, they're banking their livelyhoods on you. If you don't find the fish, or worse yet, fly right over them without noticing, no one on the boat makes a dime. For that reason, captains tend to be real reluctant to bank on a pilot who has yet to prove that he knows how to find fish. So it becomes the classic can't get hired without experience, can't get experience without getting hired type of thing. If you have an opportunity to get hired, don't waste it.
There's a whole laundry list of clues pilots look for when searching for fish and most of them are very subtle and easy to miss. Being able to reliably find the fish and put the boat on them is definitely a skill. And of course not only do you have to be able to find the fish, you've got to be able to find the right kind of fish. The guys on a sword boat are not going to be amused if you lead them to a school of dolphin.
Beyond that, you need a plane that can carry as much fuel as humanly possible and you need to learn to make that fuel last as long as possible. One of the guys I met had a supercub with 5 or 6 tanks. He could (and regularly did) keep it in the air for almost twenty hours IIRC. You also need a BFAC which stands for big effin alarm clock. The boat stays out on the water and fishing starts at sunrise. That means they want you in the air and over the fishing grounds by first light. Sorry guys, I overslept is not a phrase that will keep you employed.
Spotting is nice work if you can get it and can be very lucrative if you've got a good eye and get a good rep. The supercub guy I mentioned has been known to take home $30k in a month of tuna fishing.
