Trawls

Trawls are cone-shaped nets with two, four, or more panels, ending in a bag. They are towed at midwater or near the bottom, and held open horizontally by heavy doors (<i>otter trawls</i>), by beams, or by the tension created by lines connecting the net to two separate vessels (<i>pair trawls</i>). The net opening is sustained vertically by floats and weights. Fish size and species is controlled by mesh size; pelagic, demersal, and benthic fish can be targeted. The recent development of trawls with large wheels (<i>rockhoppers</i>) prevents damage and tangling of nets, and has eliminated the disincentive to trawling along rugged seafloors.
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For more detailed information, please visit the FAO Fisheries and Aquaculture Department <a href="http://www.fao.org/fishery/geartype/103/en" target="_blank">trawl nets</a> web page.

Displaying 11 - 20 of 119

Study Type: 

Field study in the wild

Location: 

Guyana

Target catch: 

Seabob shrimp (Xiphopenaeus kroyeri)

Effect on bycatch species: 

40% decline in elasmobranch catch rate; mean size of elasmobranch captured reduced by 6.3%

Effect on target catch: 

Not tested

Article: 

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Reduction technique: 

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Study Type: 

Field study in the wild

Location: 

Newport, Oregon, USA

Target catch: 

Pacific hake (Merluccius productus)

Effect on bycatch species: 

Artificial illumination can influence where Chinook salmon exit out of a bycatch reduction device, and can be used to enhance overall escapement.

Effect on target catch: 

Not tested

Article: 

Bycatch species: 

Reduction technique: 

Fishing Gear: 

Study Type: 

Field study in the wild

Location: 

Finnmark (northern Norway)

Target catch: 

Demersal fish

Effect on bycatch species: 

Escape behavior of haddock can be triggered by mechanical stimulation and were slightly affected by light. Cod did not react significantly to the presence of mechanical stimulation or LED light stimulation.

Effect on target catch: 

Not tested

Bycatch species: 

Reduction technique: 

Fishing Gear: 

Study Type: 

Field study in the wild

Location: 

Mediterranean Sea

Target catch: 

Demersal fish

Effect on bycatch species: 

Unknown (no turtles captured in either control or experimental trawls)

Effect on target catch: 

No significant loss of commercial weight of fish, similar rates of capture without any significant loss of sizes (with the exception of anglerfish), significant reduction of debris in the codend

Article: 

Bycatch species: 

Reduction technique: 

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Study Type: 

Field study in the wild

Location: 

Eastern Pacific Ocean

Target catch: 

Tuna

Effect on bycatch species: 

Porpoises could not get their snout through 1 inch mesh panel.

Effect on target catch: 

N/A

Article: 

Bycatch species: 

Reduction technique: 

Fishing Gear: 

Study Type: 

Field study in the wild

Location: 

Costa Rica

Target catch: 

Shrimp

Effect on bycatch species: 

Significantly more elasmobranchs caught in water <100 m. Four species made up 66% of the elasmobranch bycatch.

Effect on target catch: 

N/A

Article: 

Bycatch species: 

Fishing Gear: 

Study Type: 

Field study in the wild

Location: 

Spencer Gulf

Target catch: 

King prawn

Effect on bycatch species: 

Reduced capture of giant cuttlefish and blue swimmer crabs by 30-50%

Effect on target catch: 

Catch of target species was not affected

Article: 

Bycatch species: 

Reduction technique: 

Fishing Gear: 

Study Type: 

Field study in the wild

Location: 

US West Coast

Target catch: 

Flatfish

Effect on bycatch species: 

83.7% (weight) and 74.3% (number) of Pacific halibut were able to escape

Effect on target catch: 

93.3% of arrowtooth flounder, 99% of Dove sole, 96.9% of petrale sole, 96.9% of shortspine thronyhead and 90% of sablefish were retained

Article: 

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Reduction technique: 

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