For Jst Maro key attributes for his fishing hobby would be Positioning, Stamina and Agility
At fishing for good catch first you need to find yourself good spot, where fishes are in abundance. Maro is very week in this attribute with only 9, that is why he very rarely find good spot for fishing.
Next skill is stamina. You need to be patient to catch a fish and once you got it, there might be a long fight to get it out. Maro have very good stamina (14) for young player that is why he can be out there for a very long time and also can fight with fish for almost an hour.
To get a fish out of the water you need agility. Speed, balance and stickchecking also helps a bit but agility is most important here. With 13 agility Maro is capable of geting big fish out of water.
So in last two years Maro improved as fisherman a lot, but he still needs guide to show him good fishing spots. If he fishes on his own he still finds and catches a lot of garbage.