Fishing Methods

ustainable fisheries are sustainable because they are very focused fisheries, catching the target species and little else. They are generally active, not passive fisheries. Waste and by-catch is minimal. The catch is usually fresh. Sustainable fishery methods include encircling seine nets, long lines, Hook and line, jigging, weirs, traps, harpooning and trolling.

Finfish Harvesting Methods

TRAWLING or DRAGGING
The most common method of fishing, trawling is simply described as towing a net through the water. A trawl net is funnel-shaped, and can harvest bottom-dwelling fish when dragged along the ocean floor. Pelagic fish can be caught by mid-water trawling, in which the net is towed through the water column between the surface and the bottom.

GILLNETTING
Gillnetting can also be used to harvest bottom or pelagic fish, but is a passive fishing method. A gillnet is a wall of netting set in a straight line, equipped with weights at the bottom and floats at the top, and is usually anchored at each end. Fish swim through the virtually invisible netting, and are entangled when their gills are caught in the webbing, hence the name gillnetting. If allowed to drift freely, the method is referred to as driftnetting.

LONGLINING
Rather than a net, longlining uses baited hooks on offshoots of a single main line to catch fish at any level. The line can be anchored at the bottom in areas too rough for trawling, or set adrift, suspended by floats. Currently used to catch swordfish.

PURSE SEINES
Purse seines are walls of netting, used to encircle entire schools of fish at or near the surface. A drawstring cable is threaded through the bottom of the net. When the cable has pulled the netting tight, enclosing the fish in a pouch, the catch is hauled on board with a dip net in a process called brailing.

WEIRS
A weir is a passive fishing method consisting of brush or twine fences permanently attached to the bottom. Two prolonged fences, called leaders, direct fish to swim voluntarily into successive enclosures known as the heart, pound, and pocket.

FISH TRAPS
Similar to weirs, these traps are instead constructed with netting or wire, and are often designed to float where bottom terrain prohibits stakes or pilings. Floating traps are held in place with anchors, the bottom of the trap covered with netting.

JIGGING
Jigging is the setting of a line, with baited hooks or lures, that is continually jerked. The motion, achieved by hand or with a jigging machine, induces fish to take the hook.

HARPOONING
Used extensively in the whaling days, harpoons are still used today to catch swordfish, shark and tuna. Thrown by hand or shot by mounted guns, harpoons are each tipped with a barb which is attached to a long line with a buoy at the end. The line is free of the boat, and fish are followed with the assistance of the buoy until they tire and can be hauled aboard.

HOOK-AND-LINE
This method, involves a hand line or rod-and-reel sometimes with more than one hook.

TROLLING
Trolling is simply towing single fishing lines behind a moving boat.

Shellfish Harvesting Methods

DREDGING
Commonly used for the commercial harvesting of scallops, clams, oysters and mussels, a dredge consists of a metal rectangular frame to which a bag-shaped net of metal rings is attached. The frame's lower end is called the raking bar, and is often equipped with metal teeth used to dig up the bottom. The frame is connected to a towing cable and dragged along the sandy floor, much like a trawl net. Variations include hydraulic or jet dredges, which use pressurized water to stir up deep-burrowing clams, and suction dredges, which use pump-driven suction to suck the shellfish up a pipe to the boat.

TONGS
Various types of rakes are used to harvest clams and oysters. Basket rakes are equipped with wire mesh baskets to hold the catch, and bull rakes have very long, handles for operation from a skiff.

POTS or TRAPS
Pots or traps are often designed specifically for one type of fish or shellfish. Generally baited and equipped with one or more funnel openings, they are are weighted to rest on the bottom, with marked buoys at the surface

Fishing methods direct bycatch effects, indirect effects for community, effects upon habitats: