http://en.wikipedia.org/wiki/Birlinn
That's what I found so far, just a minor mention of fishing. I think that a noble could perhaps sponsor a shipyard, just like we build smithies. I envision it operating semi-autonomously, like a siege workship today, where you would get messages like "a ship was built today."
Maybe a nice touch for a New Economy building?
I'm not sure it is planned that their be buildings that affect the maximum amount of food or gold for a region. If there is there would have to be some serious balancing. Cities run a food deficit for a reason, if they could substantially reduce or even remove that from investment in things like fishing (for coastal cities at least) then that would throw those equations out.
