Dungeness Crab

Metacarcinus magister

Dungeness Crab

Metacarcinus magister

Other Common Names
Market Crab, Dungy (Affectionate)

Sandy Coast

Other Common Names

Market Crab, Dungy (Affectionate)

At the Aquarium

Sandy Coast

Appearance

Dungeness crabs are medium sized crabs with shells that grow to be around seven inches wide and taper in near the rear. The front of the shell has small spines that are commonly referred to as a crab’s “teeth”. Dungeness crabs have ten teeth on both sides of their eyes, and five small teeth between their eyes. Dungeness crabs can be identified by the color of their claws; Dungeness crabs have white claws while other closely related crabs have black claws.

Habitat

Sandy and muddy offshore, nearshore and estuary waters. Can also be found in rocky areas, but not as commonly.

Diet

Shellfish, fish, crustaceans

Life History

Dungeness crabs start out as small eggs measuring a little over a hundredth of an inch wide. Female crabs will carry upwards of 2.5 million eggs, typically between October and December, until they hatch, typically between January and March. Once hatched they will be free-floating microscopic plankton for about next four months, at which point the crab is considered a juvenile. They reach maturity between four and five years old. Their typical lifespan is between seven and ten years.

IUCN Status

Not Evaluated

Ecosystem & Cultural Importance

Dungeness crabs are common food for many species of animals. In south east Alaska the dungeness crab makes up 15% of the diet of the sea otters that live there. Dungeness crab make up a large fishery in Oregon with over 350 ships actively crabbing in Oregon waters. Crabs are caught in crab pots, which are special structures that allow the crab to walk in but not walk out. The commercial dungeness crab fishery catches crabs between December and August and only catches male crabs. This allows female crabs to make their eggs without being interrupted.

Southern California to southern Alaska

Dungeness crabs are commonly caught both commercially and recreationally by people across the Oregon coast. While uncommon, dungeness crabs can be found while tidepooling or exploring Oregon’s estuaries. Every December the Oregon Coast Aquarium celebrates Crab Fisheries Day where visitors can learn about both dungeness crabs and the dungeness crab fisheries in Oregon.

Like other crustaceans, Dungeness crabs molt as they grow. The crab’s shell splits apart as they shuffle back, leaving behind the old shell and revealing a new one underneath. These discarded shell molts often wash up on the beach and are mistaken for deceased crabs. Female Dungeness crabs molt between March and June, while Male Dungeness crabs molt in July and August.

The bottom of the shell has a different shape if the crab is male or female. Male crabs have a narrow triangle-shaped pattern on their underside while female crabs have a broad triangle-shaped pattern. Think lighthouse vs. pyramid!

Citations & Other Resources

Hiebert, T. C., B. A., Butler, A. L., Shanks. 2016.Oregon Estuarine Invertebrates: Rudys’ Illustrated Guide to Common Species, 3rd Edition. University of Oregon Libraries and Oregon Institute of Marine Biology.
Oregon shellfish regulations. 2024. Oregon Department of Fish and Wildlife. https://myodfw.com/articles/oregon-shellfish-regulations
Oregon Department of Agriculture. 2024. Recreational Shellfish Biotoxin Closures. https://www.oregon.gov/oda/programs/foodsafety/shellfish/pages/shellfishclosures.aspx
Dungeness Crab Commission. 2024. The Fishery. https://oregondungeness.org/fishery/
Oregon Department of Fish and Wildlife. 2023. Commercial Crab Fishery – Dungeness crab. https://www.dfw.state.or.us/MRP/shellfish/commercial/crab/index.asp

Dungeness Crab

Dungeness Crab

Other Common Names

At the Aquarium

Appearance

Habitat

Diet

Life History

IUCN Status

Ecosystem & Cultural Importance

Citations & Other Resources

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