Shellfish such as crabs and lobsters are caught using baskets or netting pots. These baskets or pots sit on the seabed, with their position marked on the surface by a floating buoy. The opening of the basket or pot is designed so that the fish can get inside easily but cannot get out.
Pots and traps are generally rigid structures into which fish or shellfish are guided or enticed through funnels that make entry easy but from which escape is difficult. There are many different styles and designs; each one has been designed to suit the behaviour of its target species. Many designs have evolved over many years to suit the coastline and seabed where it is used only changing to make use of modern materials.
In certain circumstances there may well be instances of Ghost fishing of lost pots and traps but this can be minimized by using appropriate gear and release devices. One of the main causes of gear losses is the interaction of mobile gear with static gear. Nowadays the instances of this should be fewer due to the improvements in communication between different commercial fishing sectors and the ability to accurately monitor gear placement using GPS systems.
By-catch is minimal and usually confined to small animals of the target species. This can be minimized by the use of appropriate mesh sizes in the cover netting and the use of relevant escape gaps. Any by-catch in the pots can be easily removed from the trap and released back into the sea immediately without harm.
Seabed impact with pots and traps is limited to light contact of the traps and minimal penetration of the seabed from the small anchors or weights that are used at the ends of the fleets of some gears. There may be some movement of the gear and the ropes on the seabed particularly in poor weather but this will not have much effect on the seabed.
Traps, in various forms of cages or baskets, have been used throughout the world for thousands of years to catch a wide variety of fish and shellfish. The basic design has not changed much over the years; the major changes have been in the materials that are used to make the gear. Early gear would have been made with wicker or willow, woven into a basket-form with a tapered entrance in the top, and stones inside to weight them down on the seabed. Nowadays, the pots and traps are made, along similar lines to the old wicker ones, but using modern materials such as wood, steel, plastic, etc. for the frame; this being covered with nylon and polyethylene netting.
Modern pots and traps tend to differ in shape, size and construction materials according to the behaviour of the target species, and local fishing practices. However, they will all be similar in that they will have at least one tapered entrance that makes it easy for the shellfish to enter, but very difficult for them to find their way out again. There is a big variation in the names of the different traps in different fisheries, with them being referred to most commonly as pots, creels, traps — but there will be numerous different local names for the different styles of pot. The pots are baited, usually with some type of fish. As with the pot construction, the choice of bait varies greatly with the locality and the target species, with some baits proving much more suitable for certain species than others. Despite this, it often comes down to what type of bait is readily available, and at a reasonable price.
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