post detcnztioa reveal the following differences. In the croup collected Qt one month the concentration of internally deposited Isaion vroducts vas 5 to 10 tires that of the fish collected at one year. The residual activity in the fis anplyzcd at & months post detonation averaged 2.5 pe beta activity (co equivalent) ard the beta to gacma ratfo was 1:2. | In the current analyses, fish of cocpareble size hoi a beta activity of approximtely Q.1 po end a beta to gama retio of 1:4. The largest fraction of the gross teta activity in fish collected at one ronth was contributed by material in the viscera end liver, Gmller but equal eccunts of activity vere found in the muscle and skeleton in these fish. In the fish collected at one year post detonation, in contrast to the group collected earlier, about 50 per cent of ths activity was incorporated into the skeleton with only about 10 Co oo C2 a) a oe ws : Ce per cent formd in muscle. 76