Sand Shrimp (Crangon septemspinosa)
Alternate common name: Seven-spined Bay Shrimp.
Color: Almost transparent pale to ash grey, spotted with brown or black.
Size: Up to 2.75 inches long.
Habitat: Among submerged seaweeds on sandy bottoms, salt marshes, and eelgrass beds.
Seasonal appearance: All year; move to deeper water in winter.
The sand shrimp is a small species of shrimp common to estuaries along the Atlantic coast. It has a stout, heavy body that tapers to a narrow tail. Similar in appearance to the grass shrimp, sand shrimp can be identified by a few key characteristics. The sand shrimp is flattened from top to bottom, rather than from side to side as is in the grass shrimp. Sand shrimp have only one pair of claws, which are shaped more like hooks than typical snapping claws. The rostrum, a spiny projection between the eyes of many shrimp, is short on this species.
Life History and Behavior
These shrimp can be observed in the nearshore salt marsh communities living in similar habitat to that of the grass shrimp. In the summer they are found in shallow waters, while in the winter they move into deeper waters. In the spring they migrate back into the shallow, warm estuarine waters. This shrimp is inactive during the day, burrowing in the sediment with only antennae exposed. They remain burrowed throughout daylight hours but will emerge if the sediment is disturbed. At night they are active in the benthic community, foraging for food.
Sand shrimp feed on benthic invertebrates, organic detritus, and even larval and juvenile fish. They are preyed upon by bottom-dwelling fish, comb jellies, and skates, and are subject to cannibalism by their own species.
Adapted from The Uncommon Guide to Common Life on Narragansett Bay. Save The Bay, 1998.