TRAWLING (from trawl, from OF. trauler, troller, troler, Fr. troler, to ramble, stroll, drag about; probably from MFG., Ger. trollen, to roll, run, and connected with Welsh trocn, wheel, pulley, Bret. trod, winding plant, trd, circle). One of two modes of deep-sea fishing, or of ex ploration of the depths. In Europe a 'trawl' or 'beam-trawl' is a triangular purse-shaped net, about 70 feet long. usually having a breadth of about 40 feet at the mouth. The upper part of the mouth is secured to a wooden beam which keeps the net open; this beam is supported on two upright iron frames, known as 'trawl-heads' or 'irons.' The under side of the net is made with a deeply curved margin attached to the 'ground-rope,' the whole length of it in contact with the ground. A trawl has also generally two pockets, one on each side, made by lacing to gether the upper and under parts, so that fish turning back from the cod may be caught in them. The meshes vary in size from four inches square at the mouth to an inch and a quarter square in the 'cod,' or narrow hinder end of the net. Two stout ropes about 15 fathoms long are fastened to the trawl-heads, and form a bridle, to which is shackled a towing-line 150 fathoms long. Trawling is generally in the direction of
the tide, and can be followed with advantage only on a sandy bottom or other smooth ground. The vessels employed in trawling on the Dogger bank and elsewhere near the English coast vary in size from 35 to 60 tons. Many of these trawl ers, however, stay out at sea for six weeks at a time in all seasons of the year, their fish being packed in ice, collected by fast-sailing cutters, and so conveyed to market. Cod, haddock, and similar fish are caught in great numbers by trawling; and some kinds of flat fish, as soles, are scarcely to be obtained by any other means. Smaller trawl-nets than those above described are used in bays and estuaries.
In the United States a 'trawl' is a long line anchored on the fishing ground, from which de pends a row of short lines carrying baited hooks. The device is principally used on the fishing banks. See DEEP-SEA EXPLORATION; FISHERIES.