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.

Fishing gear threat to right whales (Eubalaena glacialis) in Canadian waters and the risk of lethal entanglement

Study Type: 

summary

Location: 

Bay of Fundy and Scotian Shelf

Target catch: 

groundfish

Effect on bycatch species: 

Gillnets were determined as posing a considerable gear related threat (18% of total threat)

Effect on target catch: 

n/a

Article: 

Fishing Gear: 

Bycatch species: 

Acoustic investigation of bycatch mitigation pingers

Study Type: 

wild

Location: 

Queensland, Australia

Target catch: 

Shark

Effect on bycatch species: 

The current net/pinger configuration is adequate for humpback whales, dugongs and dolphins swimming at normal travelling speeds. The current pinger spacing is insufficient for dolphins swimming straight at the net at high speeds.

Effect on target catch: 

N/A

Article: 

Bycatch species: 

Reduction technique: 

Fishing Gear: 

Cetacean-fishery interactions in Galicia (NW Spain): results and management implications of a face-to-face interview survey of local fishers

Study Type: 

wild

Location: 

Galicia Spain

Target catch: 

Various

Effect on bycatch species: 

Substantial economic loss can occur from interactions between bottlenose dolphins and gillnets. Cetacean bycatch mortality highest for set gillnets.

Article: 

Bycatch species: 

Fishing Gear: 

Interaction between bottlenose dolphin (Tursiops truncatus) and trammel nets in the Archipelago de La Maddalena, Italy

Study Type: 

wild

Location: 

Italy

Target catch: 

Bony fish

Effect on bycatch species: 

None reported

Effect on target catch: 

Catch composition was different when dolphins attacked the net. Decrease in cuttlefish and red mullet and an increase in scorpionfish

Article: 

Fishing Gear: 

Bycatch species: 

Canadian fisheryclosures provide a large-scale test of the impact of gillnet bycatch on seabird populations

Study Type: 

summary

Location: 

Canada

Target catch: 

Cod and Atlantic salmon

Effect on bycatch species: 

Closure resulted in increased populations of common murres and auks but a decrease in gulls

Effect on target catch: 

None reported

Article: 

Bycatch species: 

Reduction technique: 

Fishing Gear: 

Test of Results

Study Type: 

wild

Location: 

Boston

Target catch: 

This identifies the target catch on the Field Study Page

Effect on bycatch species: 

This identifies the bycatch soecies on the Field Study Page

Effect on target catch: 

This is the "EFFECT ON TARGET CATTH" on the field study page

Article: 

Bycatch species: 

Reduction technique: 

Fishing Gear: 

Field Study

Study Type: 

wild

Location: 

California

Target catch: 

Swordfish and thresher shark

Effect on bycatch species: 

Decreased cetacean bycatch and no habituation. Pinniped bycatch was not significantly different

Effect on target catch: 

n/a

Article: 

Bycatch species: 

Reduction technique: 

Fishing Gear: 

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