Congaree Swamp Mollusks and Crustaceans Congaree Swamp National Monument Mollusks and Crustaceans Mollusks and crustaceans are swamp denizens. Meager poplulations may be the result of water degradation.
Mussels are extremely sensitive to environmental change.
A mollusk that was introduced into the waters of the Congaree River is the Asiatic clam. This clam has become a nuisance, overpopulating many areas and adversely impacting native species. Other mollusks found in the Congaree Swamp are snails and slugs. Visitors often see numerous holes in the trails and sloughs. These are the homes of the numerous crayfish which thrive in the wetland environment.