Fishing was the act of using a tool, such as a rod or fishnet, to catch a fish, often for the purpose of eating it. It was often done on camping trips. Among the tools used for fishing was fishing line. Those who fished where identified as a fisherman.
When William T. Riker was young, he and his father, Kyle Riker, went fishing in their home state of Alaska, where he hooked a salmon, but Kyle took the rod away and wouldn't let William reel it in, afraid that he might lose it. The younger Riker kept a photograph of himself holding the fish, despite not having caught it himself. (TNG: "The Icarus Factor")
Carl and John Torres were known for their lack of fishing skills. On one fishing trip in the 2350s, they brought their children who also went fishing, Elizabeth, Dean, Michael, and B'Elanna. (VOY: "Lineage")
In the 2360s, Jake Sisko and his father Benjamin went fishing at a pond on Earth. They brought a holoprogram of the pond to Deep Space 9 when Benjamin was reassigned there in 2369 and Jake played it aboard the starship they traveled there on. (DS9: "Emissary")