Dungeness Crab (Metacarcinus magister)

Description: The Dungeness crab is a popular food harvested along the Oregon coast. Dungeness crabs have a purple-brown carapace (the hard shell on their back). The rest of their body, including their undersides and claws, is yellow. The front half of their carapace is lined with 10 spikes on each side with the 10th being much larger and at its widest point.

Habitat: Found from Alaska to California, Dungeness crabs live in the intertidal zone amongst eelgrass or on top of sandy or muddy surfaces, and they’re also occasionally seen in Haystack Rock’s tide pools. In these habitats, they often burry themselves in the sand or under rocks.

Diet: Dungeness crabs forage for creatures living within the sand, such as shrimp, worms, mussels, clams, and even other small crabs. At the widest points on their body, male Dungeness crabs can measure 25 cm across, with females measuring up to 18 cm across.

Reproduction: If a male crab finds a female that is close to molting, he will grab onto her back to stay with her until she molts. At that point, when her shell is soft, the male will insert his sperm into the female. Females can store sperm for multiple years leading to a single clutch having multiple fathers. Each clutch may have up to 2.5 million eggs - all under one apron!

Tide Pool Tidbits:

• 25% of a Dungeness crab’s weight is edible “meat,” which is one of the highest ratios found across crab species. 

• When Dungeness crabs are cooked, their shells become a bright orange color. 

• Crabs are a type of decapod, meaning they have ten legs: eight used for walking, and two equipped with claws on the end for grabbing.

• Barnacles are often found growing on the front part of the crabs shell. They aren’t often found on the back since the crab buries itself in the sand, with only the front exposed.

Reference: Smithsonian Institution, Walla Walla University