Trawl nets are large fishing nets designed to catch fish and other marine organisms. They are typically towed behind a boat, known as a trawler, which drags the net through the water. Trawl nets can be used at various depths and are effective for capturing a wide range of species, including shrimp, cod, and herring. These nets come in different shapes and sizes, depending on the target catch and fishing method. The design often includes a cone-shaped body that funnels fish into a bag at the end. Trawling can be controversial due to its impact on marine ecosystems and bycatch, which refers to the unintended capture of non-target species.