Gill nets are panels of diamond-shaped mesh netting used for catching fish. When fish attempt to swim through the net their gill covers get caught and they cannot back out. Depending on the target species, different mesh sizes are available for use. The top line of the net has a series of floats attached for buoyancy, and the bottom line has lead weights to hold the net vertically in the water column.

Gill nets have been in use for many years. They became popular in commercial fisheries in the nineteenth century, evolving from cotton twine netting to the more modern nylon twine netting and monofilament nylon netting. As with many other aspects of commercial fishing, the use of gill nets has developed from minor utilization to a major environmental issue. Coupled with overfishing, the use of gill nets has caused serious concern throughout the world.

Because...