spear fishing (lvl 1-20)
rod fishing (faster and can catch more fish 20-40)
Hand-fishing(harder to catch, but handy and no need to use any tools 40-50)
Though my original idea was just to have anotehr tool to fish with instead of just a normal rod thing.
Im pretty sure it will work more like Blacksmithing. At any stage of blacksmithing/sword making you can try to make any type of sword without any level requirement stopping you. I also think rod fishing is easier than spear fishing.
So it could also be like this.
Rod-Fishing - easier to catch, easy to get a high quality. (lvl 15 to start getting aprox 40 ordinary fish in an hour)
Spear-Fishing - Mediocre to catch, mediocre to get a high quality. (lvl 30 to start getting aprox 40 ordinary fish in an hour )
Hand-Fishing - Hard to catch, hard to get a high quality. (lvl 50 to start getting aprox 40 ordinary fish in an hour)
Well thats just my fair idea about how it should be done.