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Species Name:    Dyspanopeus sayi
Common Name:           Say's Mud Crab

 

I.  TAXONOMY

Kingdom Phylum/Division: Class: Order: Family: Genus:
Animalia Arthropoda Malacostraca Decapoda Carpiliidae Dyspanopeus


Species Name: 
Dyspanopeus sayi Williams, 1966

Common Name(s):
Say's Mud Crab

Synonymy:
Neopanope sayi SI Smith, 1869
Neopanope texana nigrodigita Rathbun, 1934
Neopanope texana sayi SI Smith, 1869
Panopeus sayi SI Smith, 1869

Species Description:
Dyspanopeus sayi is a member of the family Carpiliidae.





II.  HABITAT AND DISTRIBUTION 

Regional Occurrence:
Say's mud crab is endemic in the Western Atlantic Ocean from Canada to Florida (Mistri 2004) and has also been found in along the Eastern Atlantic coast.

IRL Distribution:
Dyspanopeus sayi is found in the Indian River Lagoon.


III. LIFE HISTORY AND POPULATION BIOLOGY

Age, Size, Lifespan:
Individuals of Say's mud crab can live to a maximum of 2 years. Adults have a maximum carapace width of 30 mm and males reach maturity at the approximate size of 16 mm (Strieb et al. 1995). In Long Island Sound, males are reported to be more abundant than females.

Abundance:
In Long Island Sound, the density of Dyspanopeus sayi in eelgrass beds is up to 225 individuals per m2 but in open areas they are more scarce, with densities of only 0.5 m2 (Strieb et al. 1995). Recruitment of juveniles between late August and early October increases the density of Say's mud crab by 3- to 4-fold depending upon the site.

Reproduction:
Dyspanopeus sayi has separate sexes.

Embryology:
There are three zoeal stages before the megalopa.

V.  COMMUNITY ECOLOGY

Trophic Mode:
Dyspanopeus sayi uses its large crusher claw to break open the shell of shallow water bivalves (Mistri 2004).

Associated Species:
Say's mud crab takes refuge in colonies of mud-burrowing polychaetes to avoid predation by blue crabs (Heck and Hambrook 2008).


VI. SPECIAL STATUS

Fishery:
Because Callinectes ornatus occupies the same habitats as the commercial species, C. sapidus, it is impacted by the crab fishery along western Atlantic coast (Hsueh et al. 1992).


VII.  REFERENCES

Heck KL, Jr and JA Hambrook. 2008. Intraspecific interactions and risk predation for Dyspanopeus sayi (Decapoda: Xanthidae) living on polychaete (Filograna implexa, Serpulidae) colonies. Marine Ecology 12:243-250.

ITIS. Integrated Taxonomic Information System. Available online.

Mistri M. 2004. Predatory behavior and preference of a successful invader, the mud crab Dyspanopeus sayi (Panopeidae), on its bivalve prey. Journal of Experimental Marine Biology and Ecology 312:385-398.

Strieb MD, Bricelli VM, and SI Bauer. 1995. Population biology of the mud crab, Dyspanopeus sayi, an important predator of juvenile bay scallops in Long Island (USA) eelgrass beds. Journal of Shellfish Research 14:347-357.

Report by:  Melany P. Puglisi, Smithsonian Marine Station
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Page last updated: October 1, 2008