What are the Black Spots on Crab Legs?
Lets get one thing straight, the black spots on crab legs does not mean you have a diseased crab or a crab with cancer.
If you do a lot of crab fishing or cook with a lot of crabs you will sometimes notice that there are black spots, not just on the crab legs but on the larger main shell of the body as well. (It’s really noticeable on snow crab legs.)
We often get asked about black spots on crab legs and whether or not the meat inside is safe to eat. Simply put, the answer is yes -ninety-nine percent of the time, the crab meat is perfectly safe to eat.
Here’s what happens:
Crabs are known fighters and stubborn as hell. They go to battle a lot. Some end up loosing a claw or leg, some end up with wounds. The wounds are similar to a bruise that we would get, only crabs don’t have skin they have an exoskeleton.
Also, crab shells get old. They don’t last the life of the crab.
Because crabs have an exoskeleton they shed (molt) their shell. Once they have molted they get a brand new shell, that is black spot free and ready for some fresh battles.
If you find a crab that has black spots -it’s good news for you. It means that the crab hasn’t molted in a while and they are crammed full of meat. A shiny new shell might mean that there isn’e much meat on the inside.
Testing for a Soft Shell (recently molted)
On a Dungeness crab - check to see that the shell isn’t soft by pinching the bicep area of the crab claw. If the shell flexes you have a soft shell and should return it to the water.
What about the one percent that may not be safe?
Upon catching or before purchasing your crab make sure you do a full inspection of each spot. If there is a wound that made full penetration through the shell it’s a good idea to throw the crab back.
If you already have your crab at home before you noticed then you may want to cut the bruised meat away as it can a) look undesirable to eat and b) organisms may have entered the crab from this small hole.
Organisms gross!
Don’t fear, if an organism did find it’s way inside (even if you didn’t cut the bruised meat away) if you cooked your crab according to our cooking crab 101 guide then you don’t have any risk of anything terrible happening to you. Even if you already ate it and the said organism is…dare I say it…a worm. Blech!
- Crabs
- crab legs
- crab shells
Do you still have questions about black spots? Leave us your questions in the comments section below and we will be happy to answer them.
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Great explanation. Good to see someone knows what they’re talkin’ bout. Thery’re stuffed with meat!
Last night at REd Lobster, my son ordered crab legs and they had several round black things. He tried picking them off. Only the top came off to reveal a small, white worm curled up in a circle. They were dead, of course, as the legs were cooked. They were strictly on the shell and did not penetrate to the meat at all. He ate it, since the meat looked fine, but can anyone tell me what they were?
Anni, I’m sorry to hear about the worm hidden in the black spots. This freaks me out every time. Unfortunately, this happens sometimes although not too often otherwise nobody would be eating crab.
It’s really hard to answer what the worm creature was. The best way for you to find out though, is to take the shell with the worm on it (or a picture) and go to your nearest Aquarium or fisheries department. The marine biologist should be able to help with identifying it. Or, if you don’t have a picture or the shell go to the restaurant and ask them what type of crab it was (if it was a King crab which type -Red, Blue or Golden) and find out what area it was fished from then go see your local marine biologist.
I’m sorry I couldn’t answer your question. If you do find out, or have pictures can you let me know so I can post it to our readers.
Thanks for commenting, Tanis
Dearest Crab lovers,
If anyone wishes to leave a comment to help Anni with her quest to find an id. on her worm please do so but make sure you reference your source of information. Any comments without any crabbing creds cannot be published.
Thanks, Tanis