Fishery Type


Ocean Region

Indian Ocean, Eastern Pacific Ocean, Western Pacific Ocean, Northern Atlantic Ocean

Target Species

Mahi, Swordfish, Tuna

Bycatch Species

Sharks and Rays

Leaders are a segment of the branch line that the baited hook is directly attached to. When metal wire is used as the leader, it decreases the chances that the leader line breaks off and the hooked fish (or sea turtle, seabird, or mammal) escapes. However, in many of longline fisheries, this technique mostly just retains sharks caught as bycatch which would otherwise be able to cut the line with their teeth. In pelagic fisheries where it is unlikely for the fish to break off a monofilament leader, the biggest impact of steel leaders is the increase in shark bycatch. For fisheries that do not retain sharks, it is recommended to use a leader material that can be cut, allowing sharks to break off in the water, or be cut from the main line by the crew when hauling.