PREFACE The atomic energy weapons testing program, initiated with the detonation of the "Trinity" shot in New Mexico in 1945 and continued subsequently at Bikini, Eniwetok, and Nevada, has resulted in contamination of the test sites with varying amounts of radioactive materials. Some of these radioactive materials are absorbed or adsorbed by animal and plant life. understanding of the nature of such contamination, in the test areas are essential. To gain an field studies In the tests conducted at Bikini and Eniwetok the conditions are nearly ideal for study of the contamination of an aquatic environment. The Applied Fisheries Laboratory has been interested in the problems presented by disposal of radioactive wastes into water since the United States atomic energy program was initiated. Field studies have been conducted by the Laboratory at Bikini and Eniwetok since the inception of the test programs at these two atolls. The data from these studies is recorded in a number of reports prepared for the Atomic Energy Commission. ports A list of the re- is attached in the Appendix. To complete a project such as the Marine Survey of Eniwe- tok Atoll for the purpose of evaluating radiological contamination requires the combined efforts of many persons and organ- izations. We are not able to acknowledge the help and counsel of all those who aided us but of especial help were the members of the A.E.C. Division of Biology and Medicine staff in the Washington office. The A.E.C. personnel at the Hanford Works, in oe 4