Net
an open fabric used for catching animals alive. Nets have either the form of a bag, in which case they are used after the fashion of a scoop, or else they are extended curtains, in which animals become entangled. Nets are of great antiquity. They were used by primitive people not only to take fish, but to entangle birds and wild animals. A net thrown over a lion, for instance, so entangled the beast that the native hunters were able to dispatch him with their spears. The net used by children in catching butterflies is a familiar example of the bag net. Material used for such a net needs only to be light and strong and to allow the air or water to pass through it without resistance.
Fish nets are constructed frequently on the plan of a pocket. Such nets are set in the water in such a way that fish running into them are unable to find their way out. The drag net, used by fishermen, is a huge pocket drawn along the bottom of the sea. The casting net is a circular net weighted at the margin. This the fisherman throws out so as to cover a circular space of water. The weighted edges drop at once, forming a sort of pouch around any fish that may happen to be under the net.
Ordinary fishing nets, however, are entirely without pockets. They may be made of any strong twine that does not rot readily in water. The cords cross each other at right angles, and are tied with fixed knots that will not slip. The intervening spaces are called meshes. The strength of the cord and the size of the mesh are adapted to the strength and size of the fish which it is designed to catch. This sort of net is usually weighted along one edge with pieces of lead and buoyed at the opposite edge with pieces of cork, causing the net to assume a vertical position in the water somewhat like a wire fence. In attempting to pass through the net the fish become entangled, so that they can go neither forward nor backward. When the net has been set for a sufficient length of time, the fishermen pass along with a boat, raise the net out of the water, and take out the fish. If the fish are too large for the net, they cannot work their way into it and are not caught, or they may be so large as to break the net. On the other hand, fish too small for the net pass through the meshes without becoming entangled. In seining for some kinds of fish the net is allowed simply to float on the surface of the sea.
Nets vary in size from the minnow net, which affords sport for the urchin, to nets five miles in length. The fisherman's net is a valuable piece of property. Sometimes a few swordfish darting through a net will do more damage than an owner can repair in a week's time. In order to prevent rotting, nets should either be kept under water or else spread out to dry.