People have dug up sources in the past of Caspian saying there might not only be fishing, but things like 'fish farms'.
Ontop of that, you should check out the recently teased skill flower that shows there is a fishing skill tree and a tonne of different fishing knowledge trees.
There are boats that will exist at launch, and they have done a promotional before selling different kinds of boats including a row boat, sail boat, barge and a big trading boat called a Cutter.
Hop into Discord some time and I can hook you up.