SURVEY OF RADIOACTIVITY IN THE SEA AND IN PELAGIC MARINE LIFE WEST OF THE MARSHALL ISLANDS SEPTEMBER 1-20, 1956 INTRODUCTION The amount of radioactivity in the sea and in pelagic marine life during and following weapons tests at the Pacific Proving Ground has been the subject of reports by United States and Japanese laboratories. Following the 1954 test series, the Japanese survey ship, Shunkotsu-Maru, made 4 general survey of the amount and distribution of radioactivity in sea water and in some of the marine life in the region west of the Marshall Islands. The re- port of the Japanese survey - indicated that measurable amounts of radicactivity were to be found in the sea even as late as the spring of 1955. Operation Troll ~ was conducted during the spring of 1955 to measure the level of radioactivity in the sea and the movement of the water mass containing the radioactivity. This was a joint operation of the New York Operations Office, U. 3S. Atomic Energy Commission, Scripps Institute of Oceanography,