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Scallop dredge
 
 
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A fishing dredge, also known as a scallop dredge, oyster dredge, etc, is a kind of dredge
Dredge

Dredging is an excavation activity or operation usually carried out at least partly underwater, in shallow seas or fresh water areas with the purpose of gathering up bottom sediments and disposing of them at a different location....
 which is towed along the bottom of the sea by a fishing boat in order to collect a targeted edible bottom-dwelling species. This technique is sometimes used in fishing for such species as scallop
Scallop

A scallop is a Marine bivalve mollusk of the Family Pectinidae. Scallops are a wiktionary:cosmopolitan family, found in all of the world's oceans....
s, oyster
Oyster

The common name oyster is used for a number of different groups of bivalve mollusks, most of which live in marine habitats or brackish water....
s, various species of clams
CLaMS

CLaMS is a modular chemistry transport model system developed at J?lich Research Centre, Germany. CLaMS was first described by McKenna et al and was expanded into three dimensions by Konopka et al ....
, crabs, and even in some cases sea cucumber
Sea cucumber

Holothuroidea is a class of marine animals with an elongated body and leathery skin, which is found on the sea floor worldwide. Many holothurian species and genera, informally known as sea cucumbers, are targeted for human consumption....
s.. The dredge is then winch
Winch

A winch is a mechanical device that is used to pull in or let out or otherwise adjust the "tension" of a rope or wire rope . In its simplest form it consists of a spool and attached hand crank ....
ed up into the boat and emptied.

The dredge is usually constructed from a heavy steel frame in the form of a scoop.






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A fishing dredge, also known as a scallop dredge, oyster dredge, etc, is a kind of dredge
Dredge

Dredging is an excavation activity or operation usually carried out at least partly underwater, in shallow seas or fresh water areas with the purpose of gathering up bottom sediments and disposing of them at a different location....
 which is towed along the bottom of the sea by a fishing boat in order to collect a targeted edible bottom-dwelling species. This technique is sometimes used in fishing for such species as scallop
Scallop

A scallop is a Marine bivalve mollusk of the Family Pectinidae. Scallops are a wiktionary:cosmopolitan family, found in all of the world's oceans....
s, oyster
Oyster

The common name oyster is used for a number of different groups of bivalve mollusks, most of which live in marine habitats or brackish water....
s, various species of clams
CLaMS

CLaMS is a modular chemistry transport model system developed at J?lich Research Centre, Germany. CLaMS was first described by McKenna et al and was expanded into three dimensions by Konopka et al ....
, crabs, and even in some cases sea cucumber
Sea cucumber

Holothuroidea is a class of marine animals with an elongated body and leathery skin, which is found on the sea floor worldwide. Many holothurian species and genera, informally known as sea cucumbers, are targeted for human consumption....
s.. The dredge is then winch
Winch

A winch is a mechanical device that is used to pull in or let out or otherwise adjust the "tension" of a rope or wire rope . In its simplest form it consists of a spool and attached hand crank ....
ed up into the boat and emptied.

The dredge is usually constructed from a heavy steel frame in the form of a scoop. The frame is covered with chain mesh which is open on the front side, which is towed. The chain mesh functions as a net
Fishing net

A fishing net or fishnet is a Net that is used for fishing. Fishing nets are meshes usually formed by knotting a relatively thin thread....
.

Early dredges had teeth, called tynes, at the bottom. These teeth raked or ploughed the sand and mud, digging up buried clams. This design was improved by using spring-loaded teeth that reduced bottom snagging, and so could be used over rough ground.

Dredge nets have a coarse mesh in order to let organisms smaller than the target species through. The net catches the larger organisms: in the case of scallop dredging that includes the scallops' predators, such as whelk
Whelk

A whelk is one of several species of large sea snails, marine gastropod mollusks found in temperate waters.In North America, the word whelk is used for "busycon whelks", several species of large, usually edible Busycon snails, marine gastropod mollusks in the family Melongenidae....
s, starfish and octopus
Octopus

The octopus is a cephalopod of the order Octopoda that inhabits many diverse regions of the ocean, especially coral reefs. The term may also refer to only those creatures in the genus Octopus ....
.

In some cases several dredges are attached to a wheeled rigid axle in groups of three or four. A number of these dredges can be towed from a heavy spreading bar, usually one from each side of the vessel. The length of the bar and number of dredges towed depends on the power of the vessel and the room on the side deck for working the dredges. The number might be 3 on each side on a small 10 metre boat up to 20 on each side for a 30 metre vessel with 1500hp. The great weight and strength of the gear can disturb the ground it is towed over, overturning rocks and dislodging and crushing organisms in its path.