To design and construct a trap, it is generally necessary to know something of the habits of the fish to be caught. Hedge-baulks and fishing weirs are fairly extensive enclosures made of brushwood, basket work, stakes or stones, constructed on the foreshore in such a way that at high tide the sea carries the fish into the enclosure and leaves them there when it recedes. These fishing weirs are probably the primitive origin of most forms of fishing nets.

The crab or lobster pot or creel is constructed of basket-work, in shape somewhat like a safety inkpot, so that the lobster or crab can easily enter it, but, once in, is unable to escape. Lobster pots, suitably baited with fish and weighted, are distributed over the fishing ground—a rocky bottom full of crevices—from small, open boats, and are gathered the next day.

Fishing with hook and line is also a very ancient method. Before the discovery of metals, the hooks were made of bone. Some people—notably the Chinese—frequently use unbaited hooks, and rely upon the jerk of the hook at the right moment to secure the fish. Generally, however, the hook is suitably baited, the method being used chiefly for fish that seek their food by scent or sight, e.g. cod and shark. Line fishing for cod is still employed on a large scale off the North of Scotland and the coast of Newfoundland.

In lining, the fish are caught individually. A “line” may be as much as seven miles long. Short pieces of line from two to three feet long are attached to it at regular intervals. These lines are called the “snoods,” and carry the hooks. The line is usually shot at night, and fished in the morning. In most cases line fishing is rapidly being superseded by trawling.

The invention of netting marked a notable advance in the primitive development of the fishing industry. The net in all its various forms and applications is the characteristic and all-important implement of the fishing industry. A net may be used either to surround a fish and drag it out of the water, as in seining or trawling, or it may be used to enmesh the fish, as in drift netting. The rise and development of the sea fishing industry has been due very largely to the gradually improved efficiency of the net.

Nets were originally used on the shore. A long strip of netting was attached to upright stakes, to form an enclosure with an opening towards the sea, constructed like a fishing weir in such a way that the fish enter the enclosure at high tide and are unable to escape. Such devices constructed on shore are known as “fixed engines”; they include stake nets, poke nets, stream nets and purse nets. The net may simply form the wall of an enclosure (stake net). This enclosure may be furnished with a pocket at one corner (poke net). It may consist essentially of one long, deep pocket kept open by rings or stakes at intervals (purse and hose nets). It may be simply a wall of netting into which the fish thrust their heads; owing to their gill openings they are unable to withdraw and so become entangled (stream net).

The first development of a movable net was the seine or drag net. The seine is a semi-circular drag net, which is shot in shallow water so as to enclose an area of water close to the shore. It is then hauled ashore, and gathers up the fish that are in the enclosed area of water. Such a net is limited to inshore use. Generally, a line is attached to each end of the net. The free end of one of these lines is made fast to the shore by a stake, and the net is paid out from a small boat. When the whole of the net has been paid out, the boat travels round until the net forms a semi-circle of which the diameter is parallel to the shore; the net is then hauled in.

The seine net was used in ancient times by Phoenicians, Greeks, and other Mediterranean peoples. Various types of seines are in common use to-day. In Denmark a seine net is employed to catch eels and plaice. On the Cornish coast pilchards are caught with a large seine up to two hundred fathoms long and eight fathoms deep. In the United States a seine is used in water of any depth to catch mackerel. Rings are attached to the foot-rope of the net, and by passing a line through these rings and drawing it tight, the net is transformed into a bowl of netting. This is called the purse seine.