trawl

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trawl

Sea fishing
1. a large net, usually in the shape of a sock or bag, drawn at deep levels behind special boats (trawlers)
2. a long line to which numerous shorter hooked lines are attached, suspended between buoys
3. Angling another word for troll (sense 2)
Collins Discovery Encyclopedia, 1st edition © HarperCollins Publishers 2005
The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.

Trawl

 

a pass fishnet towed through the water by a special ship, called a trawler; it is designed to catch fish such as cod, haddock, banded sea perch, and other marine life.

A trawl is a conical sack of netting that is held open by rigid elements (a beam trawl) or by the hydrodynamic forces that arise when the trawl is moved (an otter trawl). The second type predominates in modern fishing. In trawling, the fish enter the mouth of the trawl and are drawn into the cod, which is the narrow end part. After the trawl is hauled on board the trawler, the cod is untied and the fish are unloaded into the hold or onto the deck.

There are several types of trawls, such as benthic, bathypelag-ic, midwater (which catch fish in the midwater, or pelagic zone), and general-purpose. The headropes of the largest trawls are up to 150 m long; the vertical opening of such nets is 30–35 m, and the horizontal opening is 50 m. These trawls pass up to 6,000 cu m of water per sec. Light and electric current are used to prevent the fish from leaving the area of the trawl. Fishing is made more efficient by the use of instruments to monitor the trawl. Such instruments make it possible to keep track of the trawl opening, the level of trawling, and the accumulation of fish in the net. The manufacture of trawls from synthetic materials, such as olefin polymers and polyamides, makes possible a reduction of the hydrodynamic resistance of the trawl and an increase in its wear-resistance and service life.

REFERENCE

Fridman, A. L., M M. Rozenshtein, and V. N. Lukashov. Proektirovanie i ispytanie tralov. Moscow, 1973.

V. V. RANENKO

The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.

trawl

[trȯl]
(engineering)
A baglike net whose mouth is kept open by boards or by a leading diving vane or depressor at the foot of the opening and a spreader bar at the top; towed by a ship at specified depths for catching forms of marine life.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.

trawl

To sift through large volumes of data (e.g. Usenet postings, FTP archives, or the Jargon File) looking for something of interest.
This article is provided by FOLDOC - Free Online Dictionary of Computing (foldoc.org)
References in periodicals archive ?
In the last week of June 1847, a group of people working under the cover of darkness destroyed six to eight trawl lines that had been set in the waters of Bryant's Cove.
Newspapers tried to maintain their enthusiasm; the Weekly Herald, for example, in relating that the Conception and Trinity Bays fisheries had been very bad, continued to hope that increased use of trawl lines, just then being introduced at Trinity, would lead to a more successful autumn fishery.
The destruction of trawl lines, the assaults on their owners, and the obstruction of cod seines do call to mind the much more famous English Luddite protests against the introduction of machinery to the textile industry.
Others, as did Kelson, believed that new methods such as seines and trawl lines were directly responsible by scaring off or diverting the migratory habits of cod.
Official support for new technology, especially trawl lines, stemmed from the manner in which Newfoundland's main competitor, France, had successfully employed bultows in a reinvigorated migratory fishery on the Grand Banks off Newfoundland after 1815.