I play with the harbor traffic mod, and it comes with maps of all the friendly ports as it modifies some of them and shows where the mines are. As far as enemy ports, I've only been in a couple so I couldn't say for sure. I think I remember coming across some quite rudely I must say in Scapa Flow, but I can't remember for sure, might've been Lock Ewe or one of the other Scotland ports.
This is a good question and hope someone out there has a map or list of enemy harbor mines? Or maybe that'd be too easy, and I shouldn't cheat and just find out on my own, can't decide. I'll let fate decide and see if anyone else replies to this post.
