Le Havre
Do I need a Fisherman to build a building that lists one after the comma in its cost?
The rulebook explains that Hammer and Fisherman symbols give bonuses and are not costs.
No. The Fisherman (and Hammer) after the comma is a symbol on the card that boosts the owner's output at the Fishery, Clay Mound, Colliery and Town Square. It is not a cost or an entry requirement, so you build with the listed resources alone.