-1G— of an end-window counter with a 2-inch Anton tube in a 3-inch Anton shield and a Nuclear-Chicago Model 181 scaler. The correction factors for geometry, self-absorption, backscatter, and decay used to convert c/m to d/m/g of wet tissue at time of collection are included in Appendix Tables D to H. The samples for total gamma counting were placed in pliofilm bags and counted in a single-channel, 50-position, automatic-advance spec- trometer with a 2-inch well-type sodium iodide crystal. Samples con- taining significant amounts of gamma activity were analyzed to determine the energies of the radionuclides present. Samples containing detectable amounts of beta activity were recounted at frequent intervals to de- termine radioactive decay. Because of the difficulties of weighing samples aboard ship, weights were determined at the Eniwetok Marine Biological the Laboratory. The radiochemical composition of nine samples was determined by ion-exchange techniques. Fish A mid-water trawl of the Isaacs-Kidd type with a spread of six (1) feet . was used to collect fish and macroplankton from depths of 14 to 365 meters. Trawl hauls were made at speeds of 4 to and for periods of 35 to 147 minutes. 5 knots A deep-sea, steam-powered anchor-winch was used for streaming the trawl with a 1/2-inch