Ghost Shrimp       Callianassa californiensis

The Ghost Shrimp burrows in muddy sand beaches with little wave action.  It is commonly found in the back end of bays of south Puget Sound.  The whitish coloration of this small shrimp gives it it’s name. The largest individuals measure 4 inches in length and live at least ten years. Large concentrations of these animals can rapidly turnover the sediments and are considered pests in oyster growing areas.

It uses its large pincers and body legs to dig out the sediment to create a burrow.  Holding the material in modified mouth parts, it transports it to the surface for disposal.  The burrow can have many branches including openings to the surface which allows for water circulation.  Using its modified hind legs, the Ghost Shrimp rhythmically moves the water through the burrow gaining oxygen and occasional plankton which it eats.  However it feeds mainly on fine organic material, called detritus, which is found in the surrounding sediments. Detritus comes from the decay and breakup of former living material and is usually covered with bacteria.  The detrital particles are strained out of the sediment using fine leg hairs and are then passed to the mouth.

The Ghost Shrimp burrow offers a home to a wide variety of other animals.  A pea crab, scale worm, a small clam whose siphons open into the burrow and a small fish called a goby all might be found in the burrow.

A similar species called the Blue Mud Shrimp (Upogebia pugettensis) is larger and more hairy with a blue cast to its body.  It has a similar life history.

Ecologically the Ghost Shrimp and the Blue Mud Shrimp serve the same function as earthworms in our lawns in that they turn over and mix the sediments bringing in oxygen and processing decaying organic matter.