[@Chenzor]Um, what? How's it difficult to carry out any of these actions?
Seriously, this smells like a deliberate artifice just to prevent people to work on more things at once.
Fishing? 20 people at best.
Farmwork? 5-20 people
Hunting and gathering?  Variable on demand
Scouting? 5-15 people
Developing new springs? 5  people at best
City guard? 15-25 people
The total count won't even approach 100. I have more than 150 able bodied adults to do anything else.
Mining, processing metals, building my city and generally anything else.

I thought this is a roleplaying game based on narrative. This sounds like deliberate gameplay limitations to me.
Oh well,  my nation technically just made its roots. So it having null actions for now can make sense.
But next time I'll be  listing a similar or even longer list of actions. 300 people may be overall small but nowhere small enough to treat them like they were just a single character. Multi-tasking is a matter of course.