Black-fingered Mud Crab

Panopeus herbstii

The black-fingered mud crab is a tiny, grayish-brown crab with:

• Powerful, black-tipped claws of unequal size.
• Major claw has a large tooth on the movable "finger" of the claw.
• Undersides of claws are pale-colored.
• Carapace, or shell, is wider than it is long, with five "teeth."
• Grows to about 1.5 inches wide.

Where does the black-fingered mud crab live?

Black-fingered mud crabs are found:

• On and around rocks, pilings, mudflats, oyster reefs, grass beds and sponge colonies in intertidal and subtidal areas.
• Range from the mouth of the Bay up to moderately brackish waters.
• May also create burrows under shells and stones.

What does the black-fingered mud crab eat?

Black-fingered mud crabs use their strong claws to crush the shells of young clams and oysters, barnacles, periwinkles and other shellfish. They will also feed on hermit crabs by seizing the hermit crab's protruding legs, then pulling it from its shell.

How does the black-fingered mud crab reproduce?

Black-fingered mud crabs spawn during the summer months. Larvae development includes:

• Four zoea stages, during which the free-swimming larvae have primitive legs and a spiny carapace.
• One megalops stage.

Other facts about the black-fingered mud crab:

• Even though it is a tiny crab, the black-fingered mud crab is the largest mud crab found in the Bay.
• Major predators of juvenile oysters in the Bay.