For other meanings of "longline", see longline.
Long-line fishing is a commercial fishing technique that uses hundreds or even thousands of baited hooks hanging from a single line. Swordfish, tuna, halibut, sablefish and Patagonian toothfish are commonly caught by this method. In some unstable fisheries such as that of Patagonian toothfish in New Zealand, fishermen may be limited to as few as 25 hooks on a line. In contrast, large commercial long-liners in certain robust fisheries of the Bering Sea and North Pacific generally run over 2500 hand-baited hooks on a single series of connected lines many miles in length. Long-lines can be set to hang near the surface (pelagic longline) to catch fish such as tuna and swordfish or along the sea floor (Demersal longline) for groundfish such as halibut or cod. Pelagic longlines are the most common commercial fishing gear in the world.