Hi. In my current game playing as the Mogawr, I have built cargo docks in my first three cities, but I still have no trade routes. It has been a few turns since I completed the cargo docks. 

Above are two of the cities, Mettanch and Suan. Are they not allowed to have sea trade with each other since they are on the same continent? Or do I need to control the sea Djord to have a trade route between the two? (I am in cold war with the cyan AI player).

My third city, Imz, is separated from Mettanch by a single sea, Zadde, which I control.

Is there any reason there shouldn't be trade routes between these cities? Or is this a bug? Thanks in advance for any help. Here are my autosaves and diagnostic files, in case they are needed.  sea trade.zip

Interesting remark and question.

And still no reply...

My tests have indicated that you need to be at peace with the owner of a peace region in order to trade through it.