Gillnets are a type of fishing gear made of netting that is designed to catch fish by entangling them. The net is typically set vertically in the water, allowing fish to swim into it. The mesh size of the net determines which species and sizes of fish can be caught, as smaller fish can pass through while larger ones become trapped. These nets are commonly used in both commercial and recreational fishing. Gillnets can be made from various materials, including nylon and monofilament, and are often deployed in rivers, lakes, and oceans. However, they can also pose risks to non-target species, such as sea turtles and marine mammals.