Gillnets

Gillnets are single, double, or triple layers of net suspended vertically in the water column. The top of the net is connected to floats (headrope), while the bottom is weighted (footrope). Adjustment of the floats and weights allows gillnets to be positioned at varying depth, depending on the target species. Gillnets are generally deployed in large numbers and trap fish either by entangling the gills or by entangling all or part of the fish body. Variation in net mesh size allows fishermen to control the size of their catch.
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<i>Set nets</i> are stationary gillnets set near the bottom or at a particular depth. A subset of set gillnets, <i> fixed nets </i> are stretched between stakes driven into the bottom in intertidal areas. In contrast, <i>drift nets</i> are unanchored and float with the current. Drift nets are mostly used near the sea surface. <i>Trammel nets</i> are multi-layered gillnets usually set near the ocean bottom. FIsh are ensnared in the middle layer, which has the finest mesh size. <i>Encircling gillnets</i> are set in a circle in shallow water. Fishers create a disturbance in the water that drives fish into the nets. Several gillnet types may be used in conjunction; combined gill-trammel nets are particularly popular.
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For more detailed information, please visit the FAO Fisheries and Aquarculture Department <a href="http://www.fao.org/fishery/geartype/107/en" target="_blank"> gillnets </a> web page.

ant

Study Type: 

wild

Location: 

Turkey

Target catch: 

turbot fish

Effect on bycatch species: 

Reduced harbor porpoise interactions with gillnet

Effect on target catch: 

Use of pingers did not signficiantly affect catch rates or size of fish caught

Article: 

Bycatch species: 

Reduction technique: 

Fishing Gear: 

Study Type: 

wild

Location: 

North Carolina, USA

Target catch: 

Spanish mackerel and spot

Effect on bycatch species: 

Significantly reduced bycatch of some shark species

Effect on target catch: 

No difference in similar mesh size in Spanish mackerel fishery or the spot fishery. The trend was for higher catch rates in modified nets in the spot fishery.

Article: 

Bycatch species: 

Reduction technique: 

Fishing Gear: 

Reduction of harbor porpoise (Phocoena phocoena) bycatch by iron-oxide gillnets

Study Type: 

wild

Location: 

Danish North Sea

Target catch: 

Cod

Effect on bycatch species: 

Reduced harbour porpoise bycatch

Effect on target catch: 

Reduced by 30%

Article: 

Bycatch species: 

Reduction technique: 

Fishing Gear: 

Study Type: 

wild

Location: 

North Carolina, USA

Target catch: 

Mixed

Effect on bycatch species: 

No difference on group size or closest approach to the net between active and control pingers

Effect on target catch: 

None

Article: 

Bycatch species: 

Reduction technique: 

Fishing Gear: 

Study Type: 

wild

Location: 

Mediterranean, Balearic Islands

Target catch: 

Red mullet

Effect on bycatch species: 

Reduced bottlenose dolphin (Tursiops truncatus) depredation

Effect on target catch: 

Increased target catch and reduced dolphin damage to the catch

Article: 

Bycatch species: 

Reduction technique: 

Fishing Gear: 

Study Type: 

wild

Location: 

Balearic Islands, Mediterranean Sea

Target catch: 

Mixed species

Effect on bycatch species: 

49% reduction in depredation rate by bottlenose dolphins (Tursiops truncatus)

Effect on target catch: 

Increased target catch (but not significant)

Article: 

Bycatch species: 

Reduction technique: 

Fishing Gear: 

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