fallout plume from the Castle Bravo nuclear test passed over Bikar about 20 hours after the shot. Based on ash from plant samples taken on March 9, the atoll was contaminated by about 1,400,000 d/m/gm of radioactive material, compared with 35,000,000 d/m/gm from the most contaminated soil samples at Rongelap Atoll, and 950 d/m/gm at Majuro Atoll, several hundred miles south of the fallout pattern. This experience led to a pre-planned aerial survey of atolls adjacent to the subsequent March 27 Castle Romeo test, timed at one and four hours after the shot. The aircraft were equipped with gamma radiation detectors designed to measure ground contamination from altitudes of 200 to 500 feet. An overflight of Bikar Island measured 0.1 mrem/hr (1 μGy) an hour after the shot, rising to 15 mrem/hr (150 μGy) three hours later. In 1962, 19 Japanese fishermen from the fishing boat Daitei Maru No. 15 were marooned on Bikar Atoll for several days before being rescued by the U.S. Coast Guard. A 1981 study of fish and invertebrates within the lagoon found that the level of radio-nucleotides in muscle tissue was within the range found in fish products imported to the US and Japanese markets. The worldwide source of seafood-borne radio-nucleotides is a result of atmospheric nuclear testing since 1945, and therefore any residual activity from the 1950s Castle series of tests contributes only a small fraction of the contamination within the lagoon's sea life. Currently, no archaeological remains of Polynesian habitation have been identified. The almost completed corroded wreck of a Japanese fishing boat lies in the north fork of the reef passage. See also Desert island List of islands Footnotes References External links UNEP Review of species subject to long-standing positive opinions: species other than corals and butterflies from Asia and Oceania Atoll Research Bulletin Archive Home Page U.S. Dept. of Energy OPENnet advanced search page, (search full text field on string "Bikar"). Plants in the Marshall Islands, A Photo Essay Sailing Ship: Manchester (1892-1900) Miramar Ship Index: Manchester Video: Bikar Atoll Pass Via Dinghy Atolls of the Marshall Islands Ratak Chain Uninhabited islands of the Marshall Islands