pyramid crab trap is slightly sturdier and can be used in waters with stronger currents. Box crab traps are made from a strong non-collapsible wire. The main advantages of this crab trap are that once the crab enters searching for the bait it cannot escape, guaranteeing a catch when the crab enters. Along with this comes the added bonus of not having to regularly check the trap. The down side of this trap is storing and transporting it since it does not collapse. Trot line crab fishing was used exclusively by commercial crabbers from 1870 to 1929, but this method has since been almost entirely replaced by the use of crab pots and crab traps. A trotline is a baited, hook-less, long line that is usually anchored on the bottom and attached to anchored buoys. This trotline is baited and after some time, the fisherman pulls the trotline up with crabs hopefully biting on the bait. Environmental effects 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. See also Fish trap Lobster trap Environment: The Derelict Crab Trap Program References External links "Deadliest Catch - How Crab Pots Work". Deadliest Catch. Discovery Channel on YouTube. June 27, 2008. Fishing equipment Crabs