If fishing becomes a skill, I would like it to be more fun than clicking the mouse button until a fish bites.
Fish skill: affects the QUALITY of fish that you can capture. (For example, in order of increasing quality: tadpole, catfish, salmon, shark,....)
My idea is the following: fish \"population\" changes randomly after a certain duration. This just means that the FREQUENCE/CHANCE of catching a fish is better at certain locations at different times!
You can choose to fish at docks, but if the \"population\" is set at low, then you will likely catch fewer fishes.
However, it would be possible to ride on a boat, and choose where you want to fish. The boat is manned by an npc, and you can tell him/her to drive to a specific fishing spot. All you really need is one person to pay the npc to drive the boat, but you can have many people hitch a ride on it. If anyone wants to go back to shore, simply tell the npc (you still have to pay to go back to the sea/lake).
There will typically be around say a dozen fishing boats scripted to move in specific locations. That should be enough for everyone.... and there are also docks or shores that might be in a fishing location.
If a location sucks, then you can tell the npc to move the boat to another location.