Please be on the lookout for blue land crabs, Cardisoma guanhumi, a non-native species to the Carolinas. Blue land crabs look like an enormous fiddler crab.
After a spate of recent reports of the blue land crab, biologists are asking North Carolinians and South Carolinians to help them learn more about where the non-native species is spreading by reporting any sightings.
The blue land crab is native along the Atlantic coast from Brazil to South Florida, but occasional sightings of the large crabs have been reported in South Carolina since 2008. The first confirmed blue land crab sighting in North Carolina occurred in summer of 2023. Researchers do not yet know the extent of the crab’s distribution throughout the Carolinas nor its impact on the environment and other wildlife. Whether the species arrived through natural expansion of its range or human-mediated sources is also not clear.
Despite their name, the crabs vary widely in color. Adult males tend to have the characteristic blue-gray coloring, but females can also be white or ash-gray, and juveniles can range from orangish to dark brown to purple. They're also unusually long-lived and slow-growing among crabs, reaching maturity at four years of age and surviving up to eleven years.
Blue land crabs are difficult to catch. In addition to their speed at retreating into burrows deep below ground, the crabs possess a large claw that they can use to dexterously defend themselves.
If you see one of these crabs, biologists encourage you to snap a photo and report the date and the location of your sighting at the link below. Biologists suspect the crabs may be more visible following heavy rains which can drive them out of their burrows.
To report sightings, click HERE. For more information, please contact Robert Corbett (Robert.email@example.com) with the NC Division of Marine Fisheries and Bronwyn Williams (firstname.lastname@example.org) with the NC Museum of Natural Sciences.