Virginia Institute of Marine Science
Dredging has a long history in Virginia's commercial fisheries. In general, dredges are scraping or digging apparatuses that harvest as they are towed behind boats under power. Mechanical dredges have been used with sail power to harvest oysters since the mid- l 800's. Crabs have been harvested by power dredges since at least 1900, while dredge fishing of clams, which reside deeper in the substrate, began somewhat later. Individual crab dredges in Virginia can be a maximum of 8 ft wide and are usually pulled in pairs for a maximum total width of 16 ft. The dredge has a scraping or combing forward bar with 4 to 6 inch-long teeth that dig crabs out of the bottom sediment. The crabs then move across the bar into a chain or mesh bag. In the dredging process many materials may become dislodged from the bottom ( e.g. rocks, macroalgae, vascular plants and other shellfish); those greater than the bag mesh will be retained throughout the towing period. Oyster dredges are similar in design to the crab dredge; however, they are usually only 4 ft wide. Clam dredges were originally similar to oyster dredges, but over the years as clam populations have declined, the teeth in the clam dredge have been lengthened to dig deeper, and the bag is sometimes replaced with a heavy metal cage constructed of welded reinforcing bar.
Fisheries -- Eastern Shore (Md. and Va.)
Luckenbach, M. W., & Wesson, J. E. (1996) Evaluation of dredge fishing activity on the seaside of Virginia's Eastern Shore, December 1994 - November 1995. Virginia Institute of Marine Science, William & Mary. doi: 10.25773/htnt-ev79