Longlining is one of the main methods used to catch fish and longline fisheries occur in most oceans and seas in the world. While there are many variations of what constitutes a longine fishery, in general there are two types - pelagic longline fisheries and demersal longline fisheries. These species are caught from 50-300 metres deep in the water on longlines suspended by floats.
Operations vary from small boats that fish close to the coast to vessels that fish on the high seas.
Vessels that fish on the high seas might have freezers of 200-300 tonnes capacity and can stay at sea for several months. Pelagic longliners might deploy longlines up to 130 km long with 3,000 hook-bearing branch lines. Branch lines are usually 30-40 metres in length and 50 metres apart on the longline, and are light enough to bob up and down in the water column in order to attract fish. Longlines are set and hauled back in on every day of the fishing operation. Species targeted include hake, ling, cod, sablefish, halibut and Patagonian toothfish.