My understanding of the "leave it in" theory has been
it is not the water that dissolves or degrades the hook
(though salt water could be an exception) but the fish
itself, it's acids. That said, I prefer cutting the hook and
removing with as little damage as possible. Removing
or using hooks w/o barbs is probably good too but I've
never done it. Until it's in my hand I have'nt caught it.

PKnTX