Predators include worms, boring snails, fishes, crustaceans, octopus, birds, sea stars, and humans. Important predators of adult softshell clams include raccoons and otters. Aging of bay clams can be done by counting the annuli on shells. Juveniles gaper clams grow to 2.5 cm after the first winter. Most gapers mature at about 70 mm shell length, 3-4 years of age.
Subtidal clams show faster growth and are larger than intertidal clams of similar ages.
Gapers can live to 16 years, reach 254 mm shell length, and weigh up to four pounds. Average size is 100-130 mm shell length. Young butter clams have little growth after settling until the following spring. The mean size at maturity is 38 mm and 3-4 years of age. Average adult size is 3-4 inches, but can reach 5 inches.