Fishermen use a wide range of gear to land their catch. Every type has its own effects on the ocean. By selecting the right gear for the right job, the fishing industry can help minimize its impact on the environment.
If their was only one way to fish, that wouldn't be fun or reliable. Everyone has different techniques they think are more adequate than others.
1. Pole/troll fishermen use a fishing pole and bait to target a variety of fish, ranging from open ocean swimmers, like tuna and mahi mahi, to bottom dwellers, like cod.
2. Purse seining establishes a large wall of netting to encircle schools of fish. Fishermen pull the bottom of the netting closed—like a drawstring purse—to herd fish into the center.
3. Harpooning is a traditional method for catching large fish—and it's still used today by skilled fishermen. When a harpooner spots a fish, he thrusts or shoots a long aluminum or wooden harpoon into the animal and hauls it aboard.
4. Traps and pots are submerged wire or wood cages that attract fish with bait and hold them alive until fishermen return to haul in the catch. Traps and pots are usually placed on the ocean bottom, often to catch lobsters, crabs, shrimp, sablefish and Pacific cod.
http://www.montereybayaquarium.org/cr/cr_seafoodwatch/sfw_gear.aspx