Why is there no fishing spit markers?

[Tully]

So they show up on the map as ? but if you try and find them on the world map, there isn't any? Do they expect me to memorize all the different fishing spots lol?

[Prolophis]

Fishing spots are part of the investigation spots marked on the map with "?".
To make the real fishing rod icon appear you have to go to that place and literally walk over the question mark.
They are always located on waterways where you can see fish swimming near the surface.
To fish instead, you have to generate bait with simple synthesis, which you have to unlock by pioneering the first region.
Surely the method for fishing, the controls I mean, are the simplest ever, that I have ever come across.

[Spaghett Meatballs]

You don't really need to return to a fishing spot again after Ligneus anyway. Unlock a fish once and the material printer goes brrrrr.