A trammel is a type of fishing net composed of three different layers of netting attached to the same lead line and float line. According to the Food and Agriculture Organization of the United Nations, trammel nets are used all over the world and are well-suited for fishing near the bottom of both inland and marine waters.
In a trammel net, fish swim through the first layer of netting and are trapped by the additional layers, explains Memphis Net and Twine Co. The two external layers of netting are usually made of nylon, while the innermost netting is typically made of monofilament or multifilament netting.
According to the Fish Net Company, monofilament netting is less visible in the water and more effective at tricking fish into the trap. However, multifilament netting is more limp and pliable, which means it is more successful at keeping fish trapped. Multifilament netting can catch fish of different sizes, while all fish caught in monofilament netting are roughly the same size. Monofilament netting can be cleaned with a simple shake and is easier on the hands, but it is less durable than multifilament netting. Multifilament netting is much harder to clean, but it is significantly stronger than monofilament netting.