Lots of questions, but we already have a lot of the answers.

National and State Regulations are already in place, with more to probably come. Local rules will also come into play. These rules limit the height and distance UAV's are legally able to fly, and also the areas they may or may not fly within.

The abilities of the UAV's and their operators also restrict what they can do. It takes a lot of experience to fly one well, and that's under good conditions. How you attach and use various equipment also takes experience, and fishing equipment is no different. Dropping sonar transmitters and fishing lures is not going to be easy. The battery life is very limited. What do you do once you drop a lure? Put the control down and pick up the fishing pole? What does the UAV do in the meanwhile? A lot of problems to overcome, and the risk to the UAV has to be figured in.

Flying miles away to check fishing spots is not going to be legal for the recreational user. I see limited uses for them in outdoor sports, some could be quite useful (checking ice), other's pie-in-the-sky.

The technology that is going to be the game changer is sonar and underwater ROVs. Not too many years from now sonar will be able to tell you the fish species and it's actual location and depth relative to the boat. No more guessing what you are looking at on the fish finder. As a scuba diver I can tell you for certain that a lot of stuff people think they know on a fish finder isn't what they think it is, I've seen it underwater firsthand.

Remote control boats can also have good uses for fishing, such as taking your lure way out past casting distance on those calm Lake Erie days. There are actually RC boats designed for fishing, with remote control compartments to put your lure in and drop it where you want. I see those being much more practical than a UAV.