|Traps, large stationary nets or barrages or pots, are gears in which the fish are retained or enter voluntarily and will be hampered from escaping.|
|These vessels are used for setting pots or traps for catching lobsters, crabs, crayfish and other similar species. |
Stationary Uncovered Pound Nets
These are usually large nets, anchored or fixed on stakes, open at the surface and provided with various types of fish herding and retaining devices. They are mostly divided into chambers closed at the bottom by netting.
Barriers, Fences, Weirs, Corrals, etc.
Gear of this type, made of various materials (stakes, branches, reeds, netting, etc.), are usually constructed in tidal waters. They differ from the fixed gillnets which, when the tide ebbs, may eventually allow the fish not entangled or gilled to pass freely underneath their bottom line.
In India, nets 12-13 m long and 1.5-2.5 m high of 10-20 mm mesh, are fixed on poles in the intertidal zone. The shape of these traps vary; they may be L-shaped, with one of the branches of the L tied to the shore; or they may consist of two parts - one straight, used to block and guide the shrimp and fish to the other part, which is curved or spiral in shape and used to trap the catch (Kurian and Sebastian, 1982). In some cases, a line of traps may be set so as to form a barrier through which nothing can pass.
Miscellaneous barriers and traps
Chinese barriers consist of a part which acts as a screen and guides the fish or shrimp towards one or several catch chambers made of screens or netting. Crosnier (1965) describes the system used in Madagascar. The trap consists of a catch chamber from which run two screens forming a V with an 80- opening. The screens which are 150 to 300 m long and 1.0 to 1.50 m high are made of strips of bamboo stakes. The average spacing between stakes is 7.5 mm (LeReste, 1971).Fishing OperationsIn Indonesia, Malaysia and SriLanka, Chinese barriers or other similardevices are used to catch young shrimp for aquaculture breeding stocks. There are various types in use. They always include a catch chamber - fixed; the catches are later collected with a scoop net, or removeable where they can either be hauled by a winch or carried ashore for the catch to be sorted. This fishery is carriecl out at night sometimes with the use of a light (Motoh, 1980).
In the Philippines, these traps are madeof two partitions made of wooden screens opening into acatch chamber (Motoh, 1980; Angeles, 1978).
In the lagoons on the Pacific coast of Mexico, small-scalefisheries using barriers (tapos) were modernized as a cooperative effort. This fishery was described by Edwards (1978). The traps block off the canals linking the lagoons to each other and retain the juveniles during the ebb stream when they are migrating from the lagoon to the sea. They consist of one or several catch chambers. The more traditional types are fitted with partitions made of wooden laths and branches. The more recent are made of galvanized steel netting; the partitions are held by solid poles, most often of cement. Two grooves are made in the poles, into which two wire netting screens of 10 mm mesh size are inserted. These new "tapos" have certain advantages over the old system: (i) maintenance is easier and does not damage the catch; the wire netting screens can be taken out to remove the leaves and branches clogging them and for repainting; one of the netting screens always remains in place so that the barrier remains in operation; (ii) this system is stronger; (iii) it is also more selective because it is easier to maintain and therefore mesh selectivity is always operating; the wire netting can retain shrimp juveniles and let post-larvae pass in the other direction (sea-lagoon). These systems are, however, much more costly than the former systems but are feasibile through cooperative fishery organizations.Vessel OverviewTraps uncovered are ususally set close to the shore in coastal waters and the use of a boat is not always necessary. Fishermen usually use open boats or canoes.Fishery Production SystemsShrimp fishing with traps is a fishing technique used by small-scale fisheries.Fishing EnvironmentGear of this type, made of various materials (stakes, branches, reeds, netting, etc.), are usually constructed in tidal waters, in lagoons and marine coastal waters. Traps can block off the whole width of a branch of a river or channel linking lagoons to each other or to the sea.Fishery AreaSuch traps are also widely used in Thailand, Sumatra, Indonesia and Sri Lanka.