The salt marsh provides a nursery ground and home for many invertebrates, including snails (univalves) and small clams (bivalves).

Fire Island forms an interface between two distinctly different marine environments: the nearshore waters of Atlantic Ocean on its southern border and the Great South Bay and other estuarine environments on its northern exposure.

The estuary is one of the most productive habitats on earth, with its phytoplankton, eelgrass beds and salt marshes. In the Great South Bay, that means home for a variety of sea life. Detritus from the marshes is washed into the bay, where it is used as food by many organisms, including mollusks.

Economically important shellfish include hard-shell clams (Mercenaria mercenaria), soft-shell clams (Mya arenaria), bay scallops (Argopecten irradians), blue mussels (Mytilus edulis) and oysters (Crassostrea virginica). These mollusks are all bivalves. Other bay bivalves include the ribbed mussel (Geukensia demissa) and (Laevicardium mortoni), and the tiny gem shells (Gemma gemma). Univalve mollusks or gastropods in the bay include mud snails (Ilyanassa obsoleta, Littorina littorea) and slipper shells (Crepidula fornicata and C. convexa).    

Shells of mollusks are occasionally washed ashore on the Atlantic beach.

The open water of the Atlantic Ocean along the southern shore of Fire Island does not provide the protection for organisms that is afforded by the less turbulent, estuarine waters of the bay. However, a number of invertebrates—including mollusks—dwell in the sand on the bottom of the continental shelf along Fire Island.

The economically important surfclam (Spisula solidissima) lives on the ocean side of the island. It is harvested far off-shore, but its shells frequently wash onto the beach. You may even see a flock of gulls fighting over one of these live mollusks on the beach. Other ocean mollusks include the bivalve razor clam (Enis directus) and the univalve conch (Busycotypus canaliculatum).  

Knowledgeable park rangers and volunteers can help you identify your shells and other beachcombing treasures.

Learn More

Visit a Fire Island National Seashore visitor center. Touch tables, exhibits, reference books, volunteers or rangers may be able to help you identify the shells you've found on the beach. 

Here you may learn more about the mollusks and other animals that once lived in these homes.

For More Information

A series of Science Synthesis Papers was published in 2005 to support the preparation of a General Management Plan for Fire Island National Seashore.

• Conservation and Management of the Living Marine Resources of Fire Island National Seashore
  (Fire Island National Seashore Science Synthesis Paper) by David O. Conover, Robert Cerrato, and William Wise, Stony Brook University, December 2005.

Additional recent studies and inventories of mollusks on or near Fire Island include:

• Surf Clam Stock Assessment
  for the Reformulation of the Shore Protection and Storm Damage Reduction Project South Shore of Long Island, New York - Fire Island Inlet to Montauk Point
  February 2002
  U. S. Army Corps of Engineers 
  
• Intertidal Wetland and Estuarine Finfish Survey of the Backbays, April 2002
  U. S. Army Corps of Engineers 
  As a part of the U.S. Army Corps of Engineers (USACE) comprehensive study to identify, evaluate, and recommend longterm measures for hurricane storm damage reduction for the south shore of Long Island, New York from Fire Island Inlet to Montauk Point (FIMP), a number of environmental studies have been completed.
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