Other forms: trawlers
A trawler is a boat that's used for fishing. Trawlers drag large fishing nets behind them.
The special nets used on trawlers are called trawls. Both words come from the Middle Dutch traghelen and its root, the Latin tragula, "dragnet." That's exactly what a trawler (also called a dragger) does—it drags a net behind it. Trawlers are controversial, because although strictly regulated, they can damage seabeds and accidentally catch fish that are endangered or too small.