Also known as “dragging,” bottom trawling uses a large net made of polyethylene to catch fish. Steel or wooden doors spread the net open. Floats are attached to the upper mouth of the net to keep it open vertically and weighted “bobbins” are attached to the lower mouth to sink the net. The bobbins’ design depends on the terrain, varying from small rubber discs for smooth sandy seafloors to large metal balls for rough ground. Known as “rock hoppers,” bobbins lift the net over obstacles on the seafloor.
In Atlantic Canada, many different species are caught in bottom trawls. These include halibut, haddock, cod, hake, redfish and pollock, among others. Each year, about 60 to 70 trawlers under 65 feet (20 metres) actively participate in this fishery. In total, 305 trawlers under 65 feet are licensed to catch haddock. These vessels account for between 42 and 52 percent of all haddock caught depending on the fishing area.