RADIOBIOLOGICAL STUDIES OF THE FISH COLLECTED AT RONGELAP AND AILINGINAE ATOLLS JULY 1957 Introduction During July 1957 collections of fish for radiobiological analysis were made at Ailinginae and Rongelap Atolls. The data from these collections represent part of the information from a continuing program of radiobiological studies which was begun on March 26, 1954, soon after the first radiological contamination of Rongelap and Ailinginae Atolls. collections were made on July 16, 1954, January 29, 10, 1955. Subsequent 1955, and October All of these investigations have been reported by Donaldson, etal. (1955). Data from the investigations in the Rongelap area bythis Laboratory and other organizations have been summarized and coordi- nated by Dunning (1957). Results of the analyses of additional material collected August 3, 1956 are included in this report. Materials and Methods Fish were collected at Enibuk Island, Ailinginae Atoll, on July 11, 1957, by poisoning an area of the inner reef. by hook and line in Mogiri Pass. One large grouper also was taken On July 17, 1957, a collection was made in the lagoon in front of the village on Rongelap Island, Rongelap Atoll, and por