If a larval clam is successful in attaching itself to the right species of fish, it becomes parasitic and the tissue of the fish grows over it, forming a nodule or lump. This parasitic state can last anywhere from 10 to 190 days depending on the species of mussel. After the parasitic stage is over and the larva has grown and developed, the young mussel falls off the host fish and drops to the bottom. Then, as nature would have it, the little clams become an important part of the food chain, even providing food for the very fish it once parasitized. If not eaten, clams will continue their growth and as they get larger, their soft inner tissues become an important food source for mink, raccoons, snapping turtles, great blue herons and other predators.
Clams can live for decades.
Recent studies in Manitoba have found freshwater mussels more than 70 years old. These long life spans are critically important to the survival of the species because it can take 10 to 20 years for some clams to become sexually mature.