Effect of Singe and Continuous Exposures of Gamma Radiation on the Survival and Growth of the Blue Crab, Callinectes sapidus

The survival and growth of young blue crabs, Callinectes sapidus, were observed after single and continuous exposures to gamma radiation. In the single-exposure experiment, crabs were given doses of 4, 8, 16, 32, or 64× 10³ rads; crabs exposed to continuous irradiation received 3.2, 7.3, or 29.0 rads/hr. The LD₅₀₍₃₀₎ value for the crabs receiving single exposures was estimated at 51,000 rads. Behavioral changes following irradiation, characterized by a loss of coordination, also appeared in these crabs. The intensity of the behavioral change decreased with decreasing radiation dose. In the continuous-irradiation experiments, survival and growth were reduced only in the crabs exposed to the highest radiation dose rate of 29.0 rads/hr. Crabs receiving the lowest radiation dose rate of 3.2 rads/hr grew at a greater rate than crabs in the other two irradiated groups and in the control group.