Not really. But in parts it's tricky, take for instance the LAA bit I mentioned.
The LAA acquired the fishing
rights back in the 19th century by adverse occupation. However, they don't own the stream bed, that (up to half way across) belongs to the farmer who owns the land. In essence anyone mooring up in the stream would be trespassing on the farmers land and anyone fishing there could be stealing the rights of the LAA. Confusing isn't it?
Won't stop me though!
Usually, whoever owns the land adjacent to the river owns the stream bed to half way and the fishing rights above that, but NOT the fish, they are feral. Until they are caught, that is, and then they belong to whoever caught them providing he did so legally with full permission from the rights owner.
(It gets worse.) However since the rules of a lot of coarse fisheries state that all fish must be returned you cannot keep it and once it is returned it becomes feral once more.