The large net used on a fishing boat is called a trawl, and to fish using this kind of net is to trawl. If you live in a coastal town, you might be able to watch the boats trawl at sunrise.
When someone trawls, they don't use a fishing pole. This kind of fishing involves a boat that's rigged with a trawl moving through the water and pulling it behind—trawling, in other words. It can be controversial to trawl, since the net can disturb the ocean floor and inadvertently catch endangered and non-edible fish. Trawl comes from the Middle Dutch traghelen, "to drag," and its Latin root tragula, "dragnet."