Dredge (trawl)
A dredge also dredge is a fastened to a heavy frame trawl to collect samples or living beings, which is pulled by a vessel along the sea bed from the base to scrape or dig. Then the net or the sample bag is pulled onto deck and the content is evaluated.
The word comes from the English expression dredge (drɛdʒ; dredging a body of water). Heavy dredges such as the chain bag dredge are suspended from a wire rope from the stern of the ship on the seabed. Then the ship pulls the dredge behind it. The frame or slide on which the sample bag hangs can be provided with steel teeth in order to remove the seabed down to the bedrock.
The target species of dredges are mostly mussels, such as oysters , mussels or scallops . Dredges are also used in mussel farms. Other possible target species are the live clams buried in the sea floor and cockles as well as sea cucumbers and crustaceans.
supporting documents
- Boat dredging. In: Fish stocks online. K. Barz, C. Zimmermann, Thünen Institute for Baltic Sea Fisheries, accessed on May 14, 2013 .