Effects of Chronic Gamma Radiation on the Growth and Survival of Juvenile Clams (Mercenaria Mercenaria) and Scallops (Argopecten Irradians)

Juvenile clams (Mercenaria mercenaria) and scallops (Argopecten irradians) from North Carolina were exposed to five intensities of chronic gamma radiation for 3–14 months during 1973–1974. Exposure rates ranged downward from 37 rads/hr to levels slightly higher than background radiation. Deleterious effects on growth and survival of clams occurred only at the highest exposure rate (37–16 rads/hr). Clams exposed to low radiation levels (0.007–0.008 rads/hr) increased in weight, but not in length, faster than the controls. One-half of the clams exposed to the highest radiation level survived to 159 days, after a cumulative dose of 132 krads, and only 10 % survived to 14 months after a cumulative dose of 150–346 krads. No deleterious effects on growth and survival of scallops were apparent during 84 days of exposure to a cumulative radiation dose of 71.7 krads.