I am going to show you how to make survival fishing equipment from natural materials. It includes fishing line and a fishing bobber. For this instructable I used the commercial hook without barb so it works in the most similar way to some improvised hook and also to make less damage to the fish. I am still working on making a hook from natural materials and I hope to add that to this instructable as soon as I realize that it works.
For the bobber you need a feather like on the first photo. It needs to be as straight as possible. I used the feather of a rook (Corvus frugilegus). If you can't find it, some stick will serve as well. Peel the feather, as in the second photo, and cut off about 1-2 cm from the thin end. Than find some stick that is soft inside, like stick from the elder tree (Sambucus nigra). Make one thin tube from the stick to fit the thin end of the feather, and another wider, to fit the wide end. You can also use the cable isolation for that.
I regularly use these bobbers, for smaller fish, they are excellent and they even fit very well to starlight glow sticks for night fishing as seen on the last photo.