PLANS, EQUIPMENT AND OPERATIONS AT SEA The amount of radioactivity in the sea vater and in ma- rine life in the region near Bikini and Eniwetok Atolls during and following the 1956 atomic testing program, as well as the movement and dispersal of the radioactivity after completion of the test program, was evaluated by two radiobiological-oceanographic surveys. The first survey, made from the Walton in June 1956, covered fifty-three stations in an area between 11° N ana 14° NW, 180 miles west of Eniwetok and 30 miles east of Bikini (UWFL-46) >. The second survey, made from the Marsh, covered 74 stations in an area bounded by 9° N and 15° NW and approximately 145° E and 166° FE (Pig. 1). This area is within the North Equatorial Cur- rent, which flows westward. In planning the track for this sur- vey it was necessary to consider the areas of fallout, the direc- tion and rate of drift of the North Equatoriel Current (taken as ten miles per twenty-four hours for planning purposes), the fuel requirements of the ship and refueling facilities, which were a- vailable only at Kwajalein and Guam. Installation of equipment aboard the Marsh was started at Eniwetok August 28 and the survey started September 1. leg, The first from Eniwetok to Guam, was completed on September 7. Marine organisms were collected from the reef on the eastern side of Guam to supplement the oceanic collections. Guam to Kwajalein, ber 17. The second leg, from covered the period from September 9 to Septen- This period was interrupted for twenty-four hours begin-