As I first posted here and as a courtesy to other forum members who one day may search for this information too, here is the gist of the advice that I received from Gui at the other forum:
There are only 2 fish farms along the portuguese coast. Both are situated at 12 and 25 miles East of Faro, almost at the Spanish border and are between 3 and 7 miles off the coast.
You can sail safely between the 7 and 25 mile line from the coast, anywhere.
Between Porto and Lisbon, be careful with the Berlengas islands, as they are true death traps, other than that, its a nice safe sail.
As a rule every day between 5pm and 7 pm, North winds blow up to 35 knots. (This is good for me because I will be heading south in a catamaran!)
Valiente, I have read that the Atlantic coasts of Portugal and Spain are heavily fished, so I am preparing for a sharp lookout on night watch. I think I will follow Guis advice and head out to around 25 miles offshore.
After my passage I'll post an update, but it might not be till the end of the summer