Clams and Mussels

• Wide range of tolerances to pollution; some are very sensitive
• Clams are more tolerant to pollution than mussels
• The larvae of mussels are parasites that live on particular fish species and depend on the fish to disperse them in the aquatic system.
• Mussels have a long life span
• It's important to make sure that the clam or mussel is alive (someone is at home) before counting it in the survey

• Two hinged shells enclose soft bodies
• Clams are smaller (3/4 inches) and more round than mussels
• Clams are usually symmetrical with the umbo (highest point on the shell) equally distant from both ends
• Mussels have a flat, oblong shell shape
• Mussels are lopsided with the umbo (highest point on the shell) closer to one end
• Soft, fleshy body (foot) may be seen extending from shell
• No eyes or distinct head