Fishing with drones is going to become a thing. There are already a bunch of flying machines that can be used for this purpose. AguaDrone is a waterproof drone with a sonar fish finder, bait drop, line casting pod, and camera that can land in and take off from fresh and saltwater. It has plug & play components.
AguaDrone lets you view images on your handheld device. It will have an open source pod for attaching your own gear. This drone is expected to ship early next year.[where to get it]