Text Size: A  A  A

Marsh Crab

Sesarma reticulatum

The marsh crab has a small, square carapace (shell) that varies in color from warm brown to dark olive. (North Carolina State Parks Natural Resources Inventory Database)
The marsh crab has a small, square carapace (shell) that varies in color from warm brown to dark olive. (North Carolina State Parks Natural Resources Inventory Database)

The marsh crab is a small shore crab that lives in salt and brackish marshes in the middle and lower Chesapeake Bay.

Appearance:

  • Small, square carapace (shell)
  • Varies in color from warm brown to dark olive
  • Eyes on stalks located at the front corners of the body
  • Two teeth toward the front on either side of the carapace
  • Notch along the middle of the carapace
  • Carapace grows to 1 inch wide
  • Furry terminal joints on the first three walking legs

Habitat:

  • Found in salt and brackish cordgrass marshes and nearby mud flats
  • Lives communally within interconnected burrows in the mud. Burrows are 25-30 inches deep and are usually filled with water. Burrow entrances, which may be an inch or more in diameter, are located near the high-tide line.
  • Most active at night

Range:

  • Found throughout the middle and lower Chesapeake Bay
  • Ranges as far north as Arundel on the Bay near Annapolis, Maryland

Feeding:

  • Eats the outermost leaves of marsh plants, especially cordgrass
  • Sometimes preys upon fiddler crabs

Predators:

  • Black-crowned night herons are known predators

Reproduction and Life Cycle:

  • Little is known about the marsh crab life cycle
  • Females may carry 5,000-13,000 eggs at a time and breed up to five times in her lifetime

Other Facts:

  • Also known as the purple marsh crab, the square-backed marsh crab and the heavy marsh crab
  • Males are known for making “rapping” sounds when defending their burrow
  • Has been linked to large losses of cordgrass in marshes on Cape Cod, Massachusetts, due to overeating

Sources and Additional Information:




Click tabs to swap between type and habitat.

410 Severn Avenue / Suite 112
Annapolis, Maryland 21403
Tel: (800) YOUR-BAY / Fax: (410) 267-5777
Directions to the Bay Program Office
Terms of Use | Privacy Policy
©2012 Chesapeake Bay Program | All Rights Reserved