Nice aesthetic :). The idea is not bad, and you can feel the pleasure of catching a fish ... at the beginning.
The beginning is very slow. It becomes faster after I upgrade my hook. However after the second upgrade, you can feel that you are doing the same thing, again and again. The gameplay doesn't evolve (or I miss something ?).
Otherwise, you miss the opportunity to implement a great atmosphere into your game. There is no music, no effects, nothing that can make the experience better. The game is too "static", and it seems that we need to work hard to get that boat. But the game is boring (for me) after the first upgrades.
In addition, I dont' like when the camera is too close to the character, showing nearly nothing around him. But this is my opinion :p.