Fishing?
This is not how to make GPS enabled games folks. Fishing? Presumably there is some x such that you will never catch a fish greater than x pounds, after which there is zero point in playing the game further. This may be a feature of the business plan, but it's certainly not good game design. "I caught a bigger bluefin tuna than you," is a sentence that will never be uttered with the same satisfaction as "I found an upgrade for my character on my hike last weekend and I am going to kick your ass. Have at you!"
Clearly, at some point in the future I am going to have to start writing the sort of games that will get my son off his ass, where he's been playing games of the sort that I'm making now.