Instrument: Beam Trawl

Acronym:

Beam trawl

External Identifier:

» skos:broadMatch http://vocab.nerc.ac.uk/collection/L05/current/24/

Description

A beam trawl consists of a cone-shaped body ending in a bag or codend, which retains the catch. In these trawls the horizontal opening of the net is provided by a beam, made of wood or metal, which is up to 12 m long. The vertical opening is provided by two hoop-like trawl shoes mostly made from steel. No hydrodynamic forces are needed to keep a beam trawl open. The beam trawl is normally towed on outriggers, one trawl on each side.

While fishing for flatfish the beam trawl is often equipped with tickler chains to disturb the fish from the seabed. For operations on very rough fishing grounds they can be equipped with chain matrices. Chain matrices are rigged between the beam and the groundrope and prevent boulders/stones from being caught by the trawl. Shrimp beam trawls are not so heavy and have smaller mesh sizes. A bobbin of groundrope with rubber bobbins keeps the shrimp beam trawl in contact with the bottom and gives flatfish the opportunity to escape.

Close bottom contact is necessary for successful operation. To avoid bycatch of most juvenile fishes selectivity devices are assembled (sieve nets, sorting grids, escape holes). While targeting flatfish the beam trawls are towed up to seven knots, therefore the gear is very heavy; the largest gears weighs up to 10 ton. The towing speed for shrimp is between 2.5 and 3 knots.

(from: http://www.fao.org/fishery/geartype/305/en)

Datasets

Dataset Name	Brief Description
Bigelow Bight fish and lg inverts	Benthic habitat correlates of juvenile fish - large inverts & fish
Cannon_2013_T1: Collection and locality information	Collection and locality information by taxon
Cannon_2014_S1: Collection and locality information	Hemichordata and Echinodermata collection and locality information
Chorion thickness E1	Chorion thickness E1
cod bycatch redux gear_fishing log	Cod by-catch reducing gear: fishing log
cod bycatch redux gear_swimming behavior	Cod by-catch reducing gear: video observations of fish behavior
cod bycatch redux_catch data	Groundfish Trawl Nets Designed to Reduce the Bycatch of Cod: catch data
Harder_2016_T1: sea spider Pallenopsis sampling sites and COI NCBI accessions	Sea spider Pallenopsis sampling sites and COI NCBI accessions
Hatch Source E1E2	Hatch Source E1E2
knotless codend_catch	Knotless Codend Mesh Selectivity: fish catch data, Gulf of Maine, 2003
Morphometrics E1E2	Morphometrics E1E2
Sand lance morphometrics
Sand lance survival	Survival of northern sand lance Ammodytes dubius offspring under factorial CO2 x temperature conditions
SECM fish size and stomach contents	Fish length, weight and stomach contents (prey) data, 1997-2006 in Southeastern Alaska
shrimp - modified nordmore_catch	Improving the Size Selectivity for Northern Shrimp Through Use of a Combination of a Modified Nordmore Grate and Square Mesh Cod End: shrimp catch data, Gulf of Maine, 2003-2004
shrimp - modified nordmore_sumry	Improving the Size Selectivity for Northern Shrimp Through Use of a Combination of a Modified Nordmore Grate and Square Mesh Cod End, Gulf of Maine, 2003-2005: summary of shrimp and fish catch results
shrimp - modified nordmore_tow metadata	Improving the Size Selectivity for Northern Shrimp Through Use of a Combination of a Modified Nordmore Grate and Square Mesh Cod End, Gulf of Maine, 2003-2004: tow chedule
shrimp nets with kites_bycatch	Use of Kites in Shrimp Codends to Reduce Small Shrimps and Bycatch Species
shrimp_nordmore_bycatch	Bycatch of regulated species and the nordmore grate in the Gulf of Maine shrimp fishery
Switch experiment E2	Switch experiment E2
Trawl abundance	Epibenthic trawl abundance from offshore of Aleutian Islands, 2016-2017
Trawl biomass	Epibenthic trawl biomass from offshore of Aleutian Islands, 2016-2017
Unhatched stages E1	Unhatched stages E1

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Database

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Instrument: Beam Trawl