radioisotopes are found in a local fallout area as compared to an area with stratospheric fallout only. In the following statement the order of presentation will be to discuss, first, the information about fallout in the ocean that has become available since the 1957 hearings and, secondly, the areas of future research. The basic concept of the ability of marine plants and animals to concentrate from the ocean certain radioisotopes of fallout remains unchanged. Additional information since 1957 as a result of the analyses of more samples and of a more thorough search for the radioisotopes that are difficult to detect has led to the confirmation of some of the previous conclusions and to a modification of other conclusions. The comparison of results of radiological analyses can not be made superficially and requires that careful consideration be given to the following three factors: (1) the completeness of the analysis; (2) the time after fallout when the collection was made and when the analysis was done; and (3) the similarity of samples as to species and tissue. The completeness of analysis depends to a great extent upon the capability of the detecting equipment and the selection of the proper radiochemical method. i no one instrument or single method of radiochemical analysis is adequate to determine the presence of all radioisotopes the presence of a radioisotope, even