Crab traps are used to bait, lure, and catch crabs for commercial or recreational use. Crabbing or crab fishing is the recreational hobby and commercial occupation of fishing for crabs. Different types of traps are used depending on the type of crab being fished for, geographic location, and personal preference.
Ring crab traps are very popular along the Oregon and Washington Coast. They are primarily used in river mouths and protected bays, but it is possible to use crab rings off the open shoreline. A crab ring is a simple piece of equipment that contains two wire rings that form the top and bottom of a collapsible basket. The lower ring is smaller than the upper ring and connected with a strong netting that forms the sides. Heavy chicken wire, cotton webbing or other suitable materials are used for the bottom.
After the bait is tied securely to the bottom of the basket, the lower basket sinks to the bay bottom where the sides collapse and the top and bottom rings lie together, leaving only a flat platform of tempting bait that the crab can easily reach. After the ring has been left on the bottom, the crabber raises the ring rapidly by pulling up with a rope, which prevents the crabs from escaping while the basket is pulled to the boat. Since the ring crab trap lays flat on the seafloor, there is nothing that prevents crabs from escaping before pulling it to the surface.
But a crab trap which becomes lost or abandoned (usually by accidental detachment of the float) becomes an ongoing environmental hazard. Crabs will continue to enter this ghost trap to eat the bait, become trapped, and starve to death, attracting more crabs and other bottom-dwelling sea life; a single trap may kill dozens of crabs in this manner. For this reason, crab traps in many jurisdictions are required to have a “rot-out panel”, a wooden panel the size of the largest entrance into the trap. This panel will disintegrate with a few weeks’ exposure to seawater, opening the trap and allowing any crabs inside to escape. Other pots use biodegradable twine, that disintegrates within less than a week.
Whales become entangled in crabbing gear. They get entangled in the vertical lines between crab traps on the ocean floor and the surface buoys. For example, as of 2014 there was an increasing number of entanglements off the coasts of the United States. Management measures have been implemented by NOAA National Marine Fisheries Service.