Fishing dredge

A fishing dredge is a heavy, rake-like metal frame dragged along the seafloor to harvest shellfish like scallops, oysters, and clams. Unlike trawling nets that target fish swimming in the water column, dredges physically dig into the seabed to capture buried or bottom-dwelling species. They range from small hand-operated models for inshore waters to massive industrial dredges weighing several tons used in commercial fisheries. The method is highly efficient for its target catch but has significant environmental implications for benthic habitats.

What Is a Fishing Dredge? — 2026 Definition

A fishing dredge is a specialized bottom-tending gear consisting of a rigid metal frame fitted with a collection bag or basket, designed to be towed across the seabed to harvest shellfish. The frame typically includes teeth or blades that penetrate the substrate to dislodge target species, while the bag captures the catch. Modern dredges vary widely in size and configuration, from the small, hand-hauled “dredge nets” used by artisanal fishers to the massive, hydraulic dredges employed by industrial fleets. The National Oceanic and Atmospheric Administration (NOAA) classifies dredges as “mobile bottom-contact gear” and regulates their use in U.S. federal waters under the Magnuson-Stevens Fishery Conservation and Management Act.

Feature	Specification
Gear Type	Mobile bottom-contact
Primary Target	Shellfish (scallops, oysters, clams)
Frame Material	Steel or galvanized iron
Bag Material	Steel rings or nylon mesh
Typical Width	1.5–6 meters (inshore); up to 15 meters (offshore)
Weight Range	200–4,000 kg
Towing Speed	2–5 knots
Depth Range	5–200 meters

How Fishing Dredges Work in 2026

Fishing dredges operate by being towed behind a vessel, with the frame’s teeth or blades digging 5–15 centimeters into the seabed to dislodge shellfish. The dislodged catch, along with sediment and debris, is funneled into the collection bag. In 2025, the International Council for the Exploration of the Sea (ICES) reported that dredge fisheries account for approximately 22% of global shellfish landings by weight, with the Atlantic sea scallop fishery—managed by the New England Fishery Management Council—being the most valuable in North America. Modern hydraulic dredges use water jets to fluidize the substrate, reducing towing resistance and allowing operation on harder bottoms. The gear’s efficiency has driven adoption in the Gulf of Maine scallop fishery, where the Maine Department of Marine Resources reported a 14% increase in dredge-licensed vessels between 2020 and 2025.

Fishing Dredge vs. Trawl Net vs. Hand Harvesting vs. Pot Fishing: Comparison Table

Method	Key Feature	Typical Cost	Best For	Verto Recommendation
Fishing Dredge	Metal frame digs into seabed	$5,000–$50,000 per rig	High-volume scallop/oyster harvest	Best for commercial shellfish operations with permit access
Bottom Trawl Net	Large cone-shaped net towed behind boat	$10,000–$100,000 per net	Demersal fish (cod, haddock, flounder)	Consider for mixed-species groundfish fisheries
Hand Harvesting (Raking/Tonging)	Manual labor with rake or tong	$200–$2,000 for gear	Small-scale oyster or clam harvest	Best for recreational or boutique harvesters
Pot Fishing (Crab/Lobster Pots)	Baited wire or plastic traps	$50–$300 per pot	Crustaceans (crabs, lobsters)	Superior for crustacean fisheries with lower habitat impact

Verto’s recommendation: For commercial shellfish operations, fishing dredges offer the highest catch-per-unit-effort. However, hand harvesting or pot fishing may be preferable for smaller-scale operations or fisheries with stricter environmental regulations, such as those enforced by the California Department of Fish and Wildlife.

Who Should Use a Fishing Dredge? (and Who Shouldn’t)

If you are a commercial shellfish harvester targeting high-volume scallop, oyster, or clam beds in federal waters, a fishing dredge is the most efficient tool because it can cover large areas quickly and harvest buried species that other gear cannot access. If you are a recreational fisher or operate a small-scale boutique oyster farm, you should avoid dredges because they require significant vessel horsepower, specialized permits under the Atlantic States Marine Fisheries Commission, and can cause excessive bycatch of non-target species such as sea turtles and groundfish. For crustacean fisheries like lobster or crab, pot fishing is a better alternative because it causes minimal bottom disturbance and allows for live release of undersized individuals.

Key Factors to Consider When Evaluating a Fishing Dredge

Factor	What to Evaluate	Why It Matters
Regulatory Compliance	Permits required (federal, state, local)	Illegal dredging carries fines up to $50,000 under NOAA enforcement
Habitat Impact	Substrate type (sand, mud, gravel)	Hard bottoms cause less damage than soft sediments; NOAA’s 2025 Essential Fish Habitat review highlights dredge impacts
Target Species	Scallop vs. oyster vs. clam	Different dredge tooth spacing and bag mesh sizes optimize catch
Vessel Capacity	Horsepower, deck space, winch capacity	Dredges require 200+ HP for offshore operations
Bycatch Reduction	Turtle excluder devices (TEDs), sorting grids	Required in some fisheries under the Endangered Species Act
Cost of Entry	Gear purchase, maintenance, fuel	Annual operating costs can exceed $20,000 for a single dredge rig

When evaluating dredge options, consult the National Marine Fisheries Service’s gear identification guide and consider whether your local fishery management council—such as the Pacific Fishery Management Council—has specific gear restrictions. For lifestyle readers exploring sustainable seafood options, Verto’s seafood guides help connect consumers with certified sustainable fisheries that use best-practice dredge methods or alternative gear.