Drift Netting

Drift netting is a fishing technique where nets, called drift nets, are allowed to float freely at the surface of a sea or lake. Usually a drift net is a gill net with floats attached to a rope along the top of the net, and weights attached to another rope along the foot of the net to keep it vertical in the water. Drift nets are placed by ships and are left free-floating until retrieved. These nets usually target schools of pelagic fish. Drift nets are a type of gill net because of the tendency for the fishes' gills to get caught in the net.

Traditionally drift nets were made of organic materials, such as hemp, which were biodegradable. Prior to 1950, nets tended to have a larger mesh size. The larger mesh only caught the larger fish, allowing the smaller, younger ones to slip through. When drift net fishing grew in scale during the 1950s, the industry changed to synthetic materials with smaller mesh size. Synthetic nets last longer, are odorless and nearly invisible in the water, and do not biodegrade.

Drift net fishing became a commercial fishing practice because it is cost effective. Nets can be placed by low-powered vessels making it fuel efficient. Drift nets are also effective at bringing in large amounts of fish in one catch.

Prior to the 1960s net size was not limited, and commercially produced nets were commonly as long as 50 kilometres (31 mi). In 1987 the U.S. enacted the Driftnet Impact, Monitoring, Assessment and Control Act limiting the length of nets used in American waters to 1.5 nautical miles (~1.7 miles). In 1989 the United Nations General Assembly (UNGA) placed a moratorium on the practice of drift net fishing. In 1992 the UN banned the use of drift nets longer than 2.5 km long in international waters.