Drifting fish aggregating devices
Fish aggregating devices not tethered to the bottom of the ocean. A DFAD typically has a floating structure (such as a bamboo or metal raft with buoyancy provided by buoys, corks, etc.) and a submerged structure (made of old netting, canvass, ropes, etc.). Its use has rapidly expanded in all the oceans. The most sophisticated DFADs include sonar and GPS capabilities so that the FAD can be geolocated and the fish population under the FAD estimated.