White-fingered Mud Crab
Rithropanopeus harrisii

Most people know that the Blue Crab is a
common resident of the Patuxent, but many are not aware that another crab
calls the river bottom home, the White-fingered Mud Crab. This is
a species that is somewhat uncommon at King's Landing although they are
captured at least a couple of times each season. It may be that the
mud crab is overlooked in our nets! This crab is very small, usually less
than one centimeter in length, although occasionally a few larger individuals
are found. This crab is much darker in color than a small Blue Crab
and may also be identified by its lack of rear swimming fins on the back
legs. Mud crabs live within the muddy bottom of the river where they
search through the mud for bits of food such as decaying plant and animal
material or they may prey upon barnacles and other small animals.