Do professions have to be learned in each area ? Ex: Do I need to learn fishing in Shadowlands and learn fishing in MoP?
Each expansion has its own profession trainers that teach recipes that were released with that expansion.
For fishing, you don’t need to know fishing for the expansion to catch fish, but you do need it to level up fishing for that expansion. Some zones or fish require you to be a certain level of fishing for that expansion to make a catch.
Professions for an expansion are separated from other previous expansions. You do not need to know MoP fishing to learn Shadowlands fishing.
However, you are still restricted to two main professions across all expansions. You can’t have different main professions for different expansions.
The first fishing trainer you find will offer all expac fishing zones.
The other trainers will only do some of their profession, but not all of the expacs. Need to find them.