Fishing net

A fishing net is a specialized tool designed to act as an improvised trap for aquatic animals.

These tools function by presenting a mesh structure to the water. Most nets are deployed in a wide, open state. They might be cast by hand or towed through the water by a vessel. When the net is retrieved, the mesh closes to engulf and trap fish. This process works because the animals are larger than the holes or gaps in the mesh. However, because nets cover large underwater areas, they often catch unwanted animals. This unintended catch is known as bycatch.

There are many mechanical ways that a net can function. A cast net is a small, circular tool with weights along its edges. A fisher throws it by hand so that it spreads across the surface and sinks. A gillnet works through a process of entanglement. It consists of a system of nets with floats and weights. The net is anchored to the seafloor and allowed to float at the surface. Fish swim into the mesh because they cannot see it. The net snags them by their gill covers, preventing them from moving forward or backward.

Other nets are designed for specific environments or species. A fyke net is a bag-shaped trap held open by hoops. These can be linked in long chains to catch eels in rivers.

A bottom trawl is a large, conical net designed to be towed along the sea floor. This method, called trawling, is used to catch demersal fish like cod or halibut. A beach seine is a long net deployed from the shore. Fishers haul it back toward the beach to encircle schooling fish. In contrast, a drift net is not anchored but moves with the ocean currents.

Humanity has relied on these tools since the Stone Age. The oldest known fishing net is the Net of Antrea, found in Finland. It was made from willow and dates back to 8300 BC.

Even older implements have been found, such as fishing sinkers in Korea dating to 27,000 BC. In ancient Egypt, tomb paintings from 3000 BC show the use of nets. The Romans also documented nets extensively in literature and art. Roman mosaics show people fishing with nets, and even gladiators used them. A specific type of gladiator, the retiarius, fought using a trident and a cast net.

Materials for net construction have evolved significantly through history. Early societies used organic fibers like grasses, vines, flax, and willow. Native Americans on the Columbia River wove seine nets from spruce root fibers or wild grass. They used cedar sticks as floats to frighten fish and keep them together. In China, hemp fibers were used for rope around 2800 BC. For a long time, hemp was the primary material for large-scale fishing gear. By 1900, cotton began to compete with hemp, and by the 1950s, cotton was used for a large fraction of nets.

The most significant change occurred with the invention of synthetic fibers. The first nylon fishing nets emerged in Japan in 1949. Nylon is a type of artificial polyamide. These nets were adopted worldwide during the 1950s, replacing hemp and cotton. Synthetic materials eventually gained dominance in the industry. For example, in Norway in 1975, 95% of all fishing gear was made of synthetic fiber. While the modern strings are much stronger, the basic design of many nets remains similar to those used in Neolithic times.

Nets also hold a place in human culture and mythology. In Norse mythology, the sea giantess Rán uses a net to trap lost sailors. The New Testament also contains references to fishing nets. For instance, Jesus is described as a master in the use of nets. Beyond myth, nets impact the modern environment. When nets are lost at sea, they become "ghost nets." These abandoned nets can continue to threaten marine life for many years.