When you think of crabs on North America's West Coast, you think of Dungeness crab — the giant, meaty crustacean that is the vital ingredient in cioppino and several other Western classics. But the Dungeness lives with another crab: the Pacific red rock crab (Cancer productus).
Although the meat of the red rock crab is as delicious as the Dungeness, the red rock crab is smaller, making the body meat in rock red crabs more difficult to extract than that in Dungeness crabs. Therefore the red rock is not as common, even though it is plentiful in the waters of the northern west coast.
Red Rock Crab's Habitat
The red rock crab (also known as just the red crab or rock crab) lives in and around rocky places — thus the name "rock crab." They are most often found in the Puget Sound in Washington state. These crabs are mean and will pinch you and are predators to hard-shelled clams and oysters.
You will most often find red and rock crabs in Asian markets; commercial catches of these crabs are minor compared to those of the Dungeness.
Red Rock Crab's Appearance
The red rock crab can grow to more than 10 inches across, but 4 to 6 inches is more common with males generally measuring 7 inches while females are more often 5 inches across the shell. Their large claws are edged in black, contrasting with the red-colored shell that ranges from light to dark red depending on where the crab lives — the farther north, the darker the shell.
The red rock is a walking crab, meaning its last set of legs is pretty much like the rest. (In Eastern blue and calico crabs, the final set of legs have flippers, making them swimming crabs.)
Red Rock Crab Male vs. Female
As with all crabs, you can tell the male from the female by the plate underneath the body: it is narrow in the male and wide in the female. The roe, bright orange stuff inside the female, is delicious and is a critical ingredient in she-crab soup. Some people also eat the green "mustard" inside the body, which is the liver.
Red Rock Crab Cooking Tips
Most of the meat is in the giant crusher claws these critters are armed with. They are virtually identical to the famed Florida stone crabs, so you can substitute red or rock crabs in any stone crab claw recipe you find.
If you come across a mess of red rock crabs, cook the claws like stone crabs — boiled in a seasoned broth and eaten with butter or mayo — and then use the bodies of all but the largest crabs to make stock or sauces.
Cracking the legs and the cleaned bodies of these crabs will give you the fixings for an outstanding tomato-based spaghetti sauce. This sauce doesn't reheat well (like many seafood dishes), so if you have lots of crabs at once, store the cooked bits in a bag and freeze until you want to make the sauce again.
If you are fortunate enough to get a hold of large red rock crabs, meaning the shell is wider than 6 inches, treat them as Dungeness and pick out all the meat for any crab recipe that suits your fancy.