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 (otter trawls), by beams, or by the tension created by lines connecting the net to two separate vessels (pair trawls). 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 (rockhoppers) prevents damage and tangling of nets, and has eliminated the disincentive to trawling along rugged seafloors.

For more detailed information, please visit the FAO Fisheries and Aquaculture Department trawl nets web page.