Types of fishing methods

Trolling and Poling

Fishing from small boats using spinning rods and bait is a traditional method of bottom fishing in coastal waters. This technique requires durable tackle and high-strength gear, as target species such as tuna can weigh up to 200 kg.

Trolling and Poling

Diving and hand collection

Commercial diving is the manual collection of certain species using scuba gear. Collection is accomplished using hooks or pliers. This commercial fishing method is used to harvest abalone, rock lobster, and sea urchin.

Diving and hand collection

Traps and pots fishing

Fishing with rectangular or cone-shaped traps is used for commercial fishing of bottom-dwelling fish (toothfish, pink perch, red emperor) and crustaceans (crab, stone lobster). The traps, baited, are lowered to the bottom. Each trap has a single entrance that opens inward. For quick retrieval, the traps are connected by cables to buoys on the surface.

Traps and pots fishing

Dredging scallop harvester

Dredge fishing is used to harvest shellfish, oysters, and scallops from the seabed. The dredge head consists of a set of metal tines mounted on a steel beam and a wire mesh into which the catch from the seabed is collected. Once filled, the dredges are lifted and unloaded onto the vessel for sorting.

Dredging scallop harvester

Purse Seine

Purse seine fishing is used to catch schooling fish that inhabit the ocean surface: herring, capelin, mackerel, bonito, and Australian sardine. A fishing vessel that catches fish using a purse seine is called a seiner.

Seiner

Before fishing, large schools of fish are located using a sonar. Floats are attached to the upper part of the net, and weights to the lower part. Afterward, an auxiliary motorboat with the end of the seine attached to it moves away from the stern of the fishing vessel and encircles the school of fish. The caught fish accumulate in the seine, which is hauled alongside the vessel. The crew then pumps the catch out using a pump or scoops.

Purse Seine

Longline

Longline fishing is a method of commercial fishing for cod, tuna, halibut, and pollock, in which baited hook gear is attached to a long line—the “longline.” Fishing vessels that use this method are called longliners. There are two types of longline fishing: midwater and bottom.

Pelagic longline

When setting the middle layer, lines ranging from 10 to 100 km in length are used, equipped with a thousand baited hooks arranged in series on the leaders, targeting apex predators (large species of tuna and sharks). Such lines are not anchored and are set to drift near the ocean surface with a radio beacon.

On more modern longliners, an automatic baiting system is used during gear deployment. The line is fed through a special device, and the crew feeds the bait fish into a chute.

Pelagic longline

Demersal (Bottom) longline

The bottom longline method is used to catch smooth Australian sharks, sawfish, and elephantfish. When setting the lower longline, the lines are anchored to the seabed using weights at depths ranging from 100 to 1,500 meters. The main line, to which the leaders are attached, is short and secured to the bottom with anchors, while at the surface it is held in place by buoys.

Demersal (Bottom) longline

Drift Set Gillnet

A drift net (gillnet) is a net with a specific mesh size. Gillnets ranging from 3 to 15 m in height can reach lengths of up to 5 km. They are set vertically in the water column using buoys and weights. Drifting with the prevailing currents, migrating sharks, tuna, and mackerel become entangled in the nets by their gills or fins.

Drift Set Gillnet

Trawl

Trawlers are the most common type of fishing vessel; they use trawl nets—known as trawls—to maximize their catch. Trawlers are equipped with trawl winches, whose drums hold up to 5,000 meters of rope—known as a trawl line—allowing them to fish at depths of up to 2 kilometers. The trawl is hauled aboard the fishing vessel via a slipway. Most modern trawlers are equipped with fish-finding equipment and facilities for primary fish processing.

Pelagic trawl

Pelagic trawling involves one or more vessels towing large nets through the water column. Trawl nets are cone-shaped with a wide funnel-shaped opening for catching fish. Trawls can be used at various depths, and the nets differ in mesh size. Midwater trawling is used to catch small fish species such as mackerel, blue mackerel, Australian sardine, and blue grenadier.

Pelagic trawl

Demersal (Bottom) trawl

The main feature of bottom trawling is maintaining contact between the trawl and the seabed during towing. This is achieved through the use of trawl boards, made of steel and attached to the lower edges of the net’s entrance. Bottom trawls are generally smaller than mid-water trawls. Bottom trawling is used to catch: flounder, sole, pink ling, grenadier, and shrimp.

Demersal (Bottom) trawl

Prawn trawl

Prawn trawling is used to catch large schools of marine fish and other seafood inhabiting various levels of the marine environment between the ocean floor and the water's surface. To adjust the depth of the underwater trawl, special weights and floats are attached to the top of the trawl, and the net itself is equipped with special net struts.

Prawn trawl

Squid Jig

Squid are caught using the jigging method in the waters of the continental shelf at depths ranging from 60 to 120 meters. Commercial fishing takes place at night on vessels specially equipped with fluorescent lamps to attract squid. Fishing is carried out using a lure attached to a line connected to a mechanical device for raising and lowering the catch. Instead of conventional fishing hooks, each lure contains dozens of barbs positioned close together. When a squid attempts to attack the jig, it becomes entangled around the vertically arranged barbs.

Squid Jig

Droplines

The dropline fishing method involves lowering a line over the side of the boat with baited hooks attached to it at intervals of 1–2 meters. A weight is attached to one end of the line, and a float to the other. After some time, the line is hauled out of the water, and the caught fish are removed from the hooks. The number of lines set per day depends on the size of the crew. On average, 5 to 10 lines are set at depths ranging from 250 to 600 m. The line is cast into the water from the stern of the fishing vessel and retrieved using a hydraulically driven winch. This method is used to fish for pink ling and sea bass.

Droplines

Whaling

Harpoon guns are used for whaling. A harpoon is a projectile weapon with a rope attached to the rear end of its shaft; the harpoon tip is either barbed or has barbed prongs, which allow it to remain embedded in the body of a whale or fish. Vessels equipped with these weapons are called harpoon vessels. As a rule, they operate as part of whaling fleets; the harpoon vessels themselves are small, and the whales they catch are processed on board commercial whaling vessels. Currently, whaling is prohibited by law in most countries; only Norway, Iceland, and Japan still engage in whaling.

Whaling ship Nisshin Maru