Fishing and farming methods

Hooks, lines, and rods

Fishing with hooks and lines is done by attracting the fish with natural or artificial bait (lures) that is fixed to the hook or at the end of a line or snood. Hooks or metallic points (jigs) are also used to catch fish by grasping the fish as they pass. Hook and line units may be used singularly or in large numbers. This type of gear is  hauled manually in small-scale fisheries while larger fisheries are usually equipped with powered line haulers, automatic jiggers, line reels, line coilers, and automatic hook handling and baiting systems.

Hooks and lines can generally be used in a very wide range of depths, either in inland waters or in the sea. Line fishing has the advantage of being able to catch fish on rough terrain, even in their hiding places in between the rocks. Several fishing methods using hooks and lines are listed below.

Pole and line

In the pole and line fishery, fishing rods are used with hooks that can be baited and can be operated manually or mechanically. This technique makes it possible to fish for species that are attracted to the surface by bait or light. Target species include tuna, mackerel, salmon, and sea bass. Fishing with poles and lines has a limited impact on the environment. Jigging is fishing with lines with lures which can be manually or mechanically moved up and down to imitate prey.

Trolling

Trolling is a fishing method mainly used to catch several species of tuna. A trolling line has baited hooks or lures and is drawn through the water by ships. The lines can hover close to the surface or be suspended down to a specific depth in the water column. The ships used for trolling vary from small, open boats to large ships of 25-30 metres that can directly freeze the catch on board. Depending on the size of the ship, up to 20 lines can be cast simultaneously. Tuna are attracted by the bait and strike from below the prey. Sometimes they even come out of the water during a strike. The tuna is then caught on the hooks and can be hauled in.  Trolling is a selective method with little bycatch. The catch can be checked on board and thrown back if needed. This method does not damage the fish which means the quality is upheld.

Drifting longlines

A drifting longline consists of a mainline kept near the surface or at a certain depth by  regularly spaced floats with evenly spaced relatively long snoods with baited hooks. Drifting longlines may be of considerable length (40-100 km). Some drifting longlines are set vertically, each line hanging from a float at the surface. This fishery targets pelagic species (like tuna and swordfish). A large problem in the drifting longline fishery (especially in tropical areas) is the bycatch of protected species like sea turtles, rays, sharks and sea birds, and problems with lost fishing gear that keeps fishing (ghost fishing). The method has a relatively low fuel use and a low impact on the ocean floor.

Set longlines

A set longline consists of a mainline and snoods with baited (occasionally unbaited) hooks at regular intervals and which is set, in general, on or near the bottom. Its length can range from a few hundred meters in coastal fisheries to more than 50 km in large scale mechanized fisheries. Target species are demersal species (like halibut and ling). A large problem in the longline fishery (especially in tropical areas) is the bycatch of protected species like sea turtles, rays, sharks and sea birds, and problems with lost gear that keeps fishing (ghost fishing) There is relatively low fuel use and low impact on the seabed.

Handlines

Handline is a general term for fishing rods, jigs, and trolling lines. Jigging uses lines with lures that are moved up and down to resemble prey and handlines are often used on a small scale and are reasonably selective. Unwanted bycatch can be thrown back immediately and usually has a high survival rate. It is more selective and small-scale than longline fishery, has no impact on the sea floor, has a low fuel use and potential bycatch can be discarded alive.

Mechanized handlines

Handline is a general term for fishing rods, jigs, and trolling lines. Jigging uses lines with lures that are moved up and down to resemble prey, mechanized jigs are often used to catch squid and cuttle fish and mechanized handlines are often used on a small scale and are reasonably selective. Unwanted bycatch can be thrown back immediately and usually has a high survival rate. It is more selective and small-scale than longline fishery, has no impact on the sea floor, has a low fuel use and potential bycatch can be discarded alive.

Harpoon

Harpoons thrown by hand are used on a small scale and are selective. They do not damage the sea floor.