sport of underwater hunting that became popular in the early 1930s and after World War II spread rapidly throughout the world. Targets of underwater hunters may include sharks and barracuda in salt water and such nongame species as carp in freshwater.

Underwater weapons range from simple hand spears to guns capable of penetrating the largest fish. The simplest weapon is the Hawaiian sling, a wooden tube with an elastic loop at one end. The shaft, which is tipped by one of a variety of spearheads, is drawn through the tube and pulled back, stretching the loop. When released, the shaft is propelled forward. In the mid-1930s, Alec Kramarenko patented an underwater gun in which the spear was propelled by a compressed spring. Shortly after, there appeared a spring-propulsion gun invented by a Frenchman, Maxime Forlot, and a popular spear gun designed by his compatriot Georges Beuchat that was propelled by a rubber elastic band. Other guns were designed that used gunpowder, carbon dioxide, or compressed air to propel the spear; one of the latter type, invented in 1956 by Juan Vilarrubis of Spain, became popular because of its accuracy, power, and simplicity of operation.

The foregoing are rifle-type weapons in which the spear either travels through a long barrel or is guided along the barrel's upper surface. In all of them the spear shaft is released by a trigger mechanism. Spearfishing guns often have a line attached to the shaft, making retrieval easier. On strike, the line holds the quarry securely.

Stalking and shooting his quarry underwater is usually only the beginning of a skin diver's battle. After a fish is hit, it must be held on a harpoon line and landed. With large fish this may mean an underwater ride as the diver is towed through the water.

Diving clubs hold yearly local, national, and international competitions in spearfishing. The competitions do not permit the use of scuba, and the contestants dive while holding their breath.

Bowfishing is a related sport in which the hunter uses a conventional bow and specially designed arrows to shoot fish that live in shallow water. Freshwater species such as carp and gar are pursued by hunters who either wade or use shallow-draft boats to maneuver in the water.