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The Nonindigenous Occurrences section of the NAS species profiles has a new structure. The section is now dynamically updated from the NAS database to ensure that it contains the most current and accurate information. Occurrences are summarized in Table 1, alphabetically by state, with years of earliest and most recent observations, and the tally and names of drainages where the species was observed. The table contains hyperlinks to collections tables of specimens based on the states, years, and drainages selected. References to specimens that were not obtained through sighting reports and personal communications are found through the hyperlink in the Table 1 caption or through the individual specimens linked in the collections tables.

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Common name: blue land crab

Synonyms and Other Names: Land crab, giant land crab, Juey (Puerto Rico)

Taxonomy: available through www.itis.gov

Identification: Eyes widespread and on stalks (Gifford 1962). Front of carapace oblique (slanting) at sides (Rathburn 1918).  Both males and females have one large major chela (front claw) and one smaller minor chela, with male major chelae growing far wider than the carapace (3 times that in older males), much larger than those of females (~5cm), with adults often exhibiting hairy legs (Gifford 1962, Rathburn 1918). Adult animals are often blue, while young animals can be variable in color from blue/blue-grey, tan, white, and females can change colors from blue to tan/purple or violet during mating periods and/or when young (Gifford 1962, Rathburn 1918). A detailed account of the morphology of the species can be found in Rathburn (1918).

Size: Carapace width up to 10-13 cm; major chelae length up to 15.5 cm (Gifford 1962, Rathburn 1918)

Native Range: Native throughout most of the Caribbean, including Bermuda, Central America and northern South America including the east coast of Mexico; present as well in West Africa (Gifford 1962, Rathburn 1918). In the United States, native to Puerto Rico (Velez 1967), Rockport Texas south to Sao Paulo, Brazil (Gifford 1962, Rathburn 1918), Florida in the southern Gulf of Mexico and South Atlantic as far north on the Atlantic coast as Vero Beach and south to the Florida Keys, along the gulf coast to Tampa (Gifford 1962). Reported in Louisiana (Behre 1949 in Gifford 1962).

The historic distribution of the species along the Gulf coast is not well-documented, and there is no documentation of the species in the Atlantic Ocean north of Vero Beach, Fl.

Alaska	Hawaii	Puerto Rico & Virgin Islands	Guam Saipan

Hydrologic Unit Codes (HUCs) Explained
Interactive maps: Point Distribution Maps

Ecology: A coastal species, not found farther inland than eight kilometers, tolerates salinity varying from 15-44 ppt, and also known to live in the ocean several meters offshore (Costlow and Bookhout 1968, Gifford 1962). Observational studies in laboratories have shown that this species prefers spending more time on land, tolerates long periods of high salinity, and can only last two days in extremely dry conditions (Gifford 1962).

This species burrows in costal or estuarine areas in colonies (Gifford 1962). Species breed from June to December in their native range in South Florida, with females attaining sexual maturity after reaching a size of 40g (Gifford 1962). Mating between males and females involves internal fertilization, after which females deposit and hold fertilized egg masses on their bodies until hatched, and after a time, travel to release the larvae into saltwater (Gifford 1962).

In Florida colonies, Cardisoma guanhumi hunts usually during the day near its burrow, avoiding direct sun light, and retreating to its burrow to feed; populations have been reported to hunt and gather at night in Caribbean areas (Herreid 1963). The species feeds on a variety of vegetation, especially the fruits and leaves of the red mangrove (Rhizophora mangle), the white mangrove Laguncularia racemose, and green buttonwood (Conocarpus erectus) (Herreid 1963). The species is mostly herbivorous but does feed on animal carcasses and is thought to engage in cannibalism (Herreid 1963).

In its native range, it is known to eat crops (Herreid 1963), is a major food source (FWC 2023, Peterson et al. 2013), and has also been known to carry salmonella (Peterson et al. 2013).

Means of Introduction: It is unclear if the northern expansion of the species along the Atlantic coast in Florida north of Vero beach up to South Carolina is directly human mediated or the result of recent range expansion. Historic records of this species north of South Florida do not exist on the Atlantic coast, and lab studies cast doubt on the species’ ability to breed in temperatures under 20°C/68°F (Costlow and Bookhout 1968).

Status: The status of this species outside of its historic range in the U.S. is not yet known. It is unclear if nonnative populations are established and breeding or overwinter and/or persist only seasonally.

Impact of Introduction:

Summary of species impacts derived from literature review. Click on an icon to find out more...

Ecological	Economic

There have been reports that land crab burrows have damaged yards and gardens where they have been introduced in South Carolina (Gibbs 2022).

References: (click for full references)

Costlow, J.D., Jr, and C.G. Bookhout. 1968. The effect of environmental factors on development of the land-crab, Cardisoma guanhumi Latreille. American Zoologist 8(3):399-410.

Florida Fish and Wildlife Conservation Commission (FWC). 2023. Recreational regulations: blue land crab. https://myfwc.com/fishing/saltwater/recreational/blue-land-crabs/. Accessed on 06/15/2023.

Gibbs, D. 2022. SCDNR: Snap photos of non-native blue land crabs. Charleston County News. Charleston County, South Carolina. https://www.counton2.com/news/local-news/charleston-county-news/scdnr-snap-photos-of-non-native-blue-land-crabs/. Created on 09/02/2022. Accessed on 06/15/2023.

Gifford, C.A. 1962. Some Observations on the General Biology of the Land Crab, Cardisoma guanhumi (Latreille), in South Florida. Biological Bulletin 123(1):207-223. https://www.jstor.org/stable/1539516.

Herreid, C.F, II. 1963. Observations on the feeding behavior of Cadisoma guanhumi (Latreille) in Southern Florida. Brill 5(3):176-180. http://www.jstor.com/stable/20141018.

Peterson, R., H. Hariharan, V. Matthew, S. Chappell, R. Davies, R. Parker, and R. Sharma. 2013. Prevalence, serovars, and antimicrobial susceptibility of Salmonella isolated from blue land crabs (Cardisoma guanhumi) in Grenada, West Indies. Journal of food protection 76(7):1270-1273. https://doi.org/10.4315/0362-028X.JFP-12-515.

Rathburn, M.J. 1918. The Grapsoid crabs of America. Bulletin of the United States National Museum.
Velez, M.J., Jr. 1967. Checklist of the terrestrial and freshwater Decapoda of Puerto Rico. Caribbean Journal of Science 7(1-2):41-44. https://citeseerx.ist.psu.edu/document?repid=rep1&type=pdf&doi=ee60bde3642402c3ecc4711a5a998fb3d0e06383.

Author: Morningstar, C.R.

Peer Review Date: 9/14/2023

This information is preliminary or provisional and is subject to revision. It is being provided to meet the need for timely best science. The information has not received final approval by the U.S. Geological Survey (USGS) and is provided on the condition that neither the USGS nor the U.S. Government shall be held liable for any damages resulting from the authorized or unauthorized use of the information.