Gillnets

Description: Gillnets are large, rectangular mesh nets that are positioned either on the sea floor or float within the water column depending on the target species. Stationary nets are anchored by weights on the bottom of the net to the sea floor and are generally kept close to shore. Drift gillnets, commonly referred to as drift nets, are kept at higher depths with buoys. The size and shape of the mesh changes according to the size of desired fish, making the gear somewhat selective. Fish swim into the net and are caught in the mesh by their gills, hence the name gillnet. The mesh size is large enough for the fish to become ensnared but not escape. After a net has been in the water for some amount of time (typically referred to as “soak time”), it is retrieved and the catch is collected, including not only the target species but other unintended bycatch.

Bycatch Threat: Gillnets are considered one of the greatest threats to the survival of marine mammals, sea turtles and some types of sea birds, including loons. Marine mammals and sea turtles become entangled in the gear, and, as they are voluntary air-breathers, are unable to come to the surface to breathe and eventually die. Seabirds, diving for food, follow a similar pattern. The problem is exacerbated by the length of time the nets are left to soak, reducing the potential for survival. Gillnets have been identified as the main cause of population decline for the vaquita, a porpoise endemic to the northern Gulf of Mexico.

Target Species:  Any ground or pelagic fish species, including cod, salmon, swordfish, halibut, tuna, etc.

Geographical Range: Globally, both inshore and offshore

Bycatch Species: marine mammals, including sea otters, porpoises, dolphins, whales; sea turtles; and seabirds.