A fishing dredge, also known as a scallop dredge or oyster dredge, is a kind of dredge which is towed along the bottom of the sea by a fishing boat in order to collect a targeted edible bottom-dwelling species. The gear is used to fish for scallops, oysters and other species of clams, crabs, and sea cucumber. The dredge is then winched up into the boat and emptied. Dredges are also used in connection with the work of the naturalist in marine biology, notably on the Challenger Expedition.
Mussel dredgers
Fishing vessel equipped with a benthic dredge, leaving the port of Nieuwpoort
Oyster boats of the Truro oyster fleet. This fishery is the last in the world to work by sail alone
Vessels dredging for oysters, c. 1875
Dredging is the excavation of material from a water environment. Possible reasons for dredging include improving existing water features; reshaping land and water features to alter drainage, navigability, and commercial use; constructing dams, dikes, and other controls for streams and shorelines; and recovering valuable mineral deposits or marine life having commercial value. In all but a few situations the excavation is undertaken by a specialist floating plant, known as a dredger.
Excavator dredger in Neeme harbour, Estonia (April 2023)
Reconstruction of the mud-drag by Leonardo da Vinci (Manuscript E, folio 75 v.)
Reconstruction of the mud-drag
The dredge drag head of a suction dredge barge on the Vistula River in Warsaw, Poland