Longlining, as the name suggests, involves long fishing lines which can be as long as 100 kilometres. Attached to them are shorter lines with baited hook tied at fixed intervals. Longlines can be set at different depths to catch different species.
Pelagic longline is where the lines are set near the surface of the water to catch open water fish such as bluefin tuna, yellowfin tuna and swordfish.
Bycatch is a major environmental issue in the longline fishery, especially impacting billfish, sea turtles, pelagic sharks, and seabirds.