Concentrations of 137Cs, 90Sr, 108mAg, 239+240Pu and atom ratio of 240Pu/239Pu in tanner crabs, Chionoecetes japonicus and Chionoecetes opilio collected around Japan

► There was no increase in the concentrations of 137Cs, 90Sr, 108mAg, 239+240Pu, and no large variation of the atom ratio of 240Pu/239Pu in the crab species collected around Japan during 1996-2007. ► The variability of the concentration of radionuclides in the crabl species results from the variablilty of the composition and quantity in the diet. ► The decrease in the concentration of radionuclides in the crab species with sampling depth depends on the concentration in the seawater and diet. ► The source of the radionuclides found in the crab species was not the radioactive wastes dumped by the former USSR and Russia and originated from past nuclear weapon tests.