Drewcifer
Agent of Karma
Perhaps I am the only one who thinks that this is a good idea but I think that empty pre-modern naval transports should be able to fish on unclaimed fish and whale resources. They could stay on the resource until they were full and then return to the port of their choice and give it a boost in food (or food and shields in the case of whales). In the modern era you could build fishing trawlers. At times you may need to use your warships to defend your fishing vessels -- as in real life.