Harpoon

long spear-like instrument used in fishing, whaling, sealing, and other marine hunting

A harpoon is a long spear-like instrument used in fishing to catch fish or large marine mammals such as whales. It does this task by impaling the target animal, allowing the fishermen to use a rope or chain attached to the butt of the projectile to catch the animal. A harpoon can also be used as a weapon.

Harpoon heads from between 15000 and 12000 BP
Inuit hunter with harpoon in kayak, Hudson Bay, circa 1908-1914

Typically, a harpoon for fishing has backwards-pointing barbs which stop the fish getting free.