The following is probably not considert a bug, but I didn`t know where to put it anyway:
I dug a little bit in the games data (uuuh bad, curious me) and found, that you could bassically selflock yourself at Terrajuma Shore. I happen to have a Mono Steel Team to this point and don't have any other Pokémon caught, except the Sewaddle from that Ninja-lady. How am I supposed to surf across the water in the cave in Terrajuma Jungle ? Because if I didnt pick up the old rod (which I didnt), I have no opportunity to catch a water Pokémon (which again, there is only Pyukumuku who can`t learn HMsurf)