I love this game, however I see that there are room for usability improvements. One small thing I noticed is there is no logical reason that fishing is required for cooking food in the tech tree.
The first time I played, had a map where I had no large body of water. The fishing skill came up and it said it would be wise to check for fish before doing this research. I had no fish, so I never researched it. Fast forward to pretty far into the mid game ( or even later? ) where I have distinct advanced technologies but still no ability to cook food. I finally decided to research fish and viola!
I think the simplest thing here is that fire building research alone should unlock cooking. It really doesn't make sense for there to be any other dependencies.