OFFICIAL USE ONLY Of the more than 700 species of reef fish at Bikini Atoll, three species commonly eaten by the Marshallese and representative of a different feeding habit were selected: the mullet, a plankton feeder; the convict surgeonfish, a grazing herbivore; and the goatfish, a bottom-feeding carnivore. The specific radionuclides found in fish and their concentrations are often associated with feeding habits, hence this was a necessary consideration in selecting samples representative of the kinds of fish which would be eaten when the Bikinians return. A fourth kind of reef fish, groupers, was also collected as representative of the higher order carnivores. The pelagic fish are all high-order carnivores and fall into two broad subcategories: resident lagoon fish (ulua, and dogtooth tuna) and migratory fish (yellowfin tuna). 4.3 Pelagic fish specimens were caught in or near Eneu Pass. BIRDS Thousands of terns nest at Bikini Atoll, mostly on the western islands. Both the birds and their eggs will be used by the natives as food. The terns usually feed at sea (outside the lagoon or reefs) while the curlews and turnstones feed along the shores and on the reef; the curlew also eats the seeds of an endemic shrub, Scaevola serica, or the beach magnolia. Both the curlews and the turnstones are present in small numbers, at most a few hundred. Although these two birds are transients, they contain the higher levels of radionuclides among the birds. 4.4 INVERTEBRATES The invertebrates sampled were the spiny lobsters (langouste), coconut crab, and "giant" clams (Tridacna sp., and Hippopus hippopus). 5. URINE SPECIMENS A single urine specimen (24 hours) was obtained from the Trust Territory resident at Bikini. Another specimen was obtained from a member of the 1970 radiological survey team who had been on Bikini for 15 days and who probably had not reached equilibrium. Analyses of these samples indicated no detectable plutonium activity. 6. SIMULATED HOUSE EXPERIMENT During the 1970 survey, a simple experiment was conducted on Bikini Island to determine how concrete living quarters made of aggregate obtained from the Eneman, Lele, Bikdrin, Aerokojlol, and Aerokoj complex reduces the exposure rate. A concrete house was simulated by constructing a large, square container with hollow walls 6-inches thick. The walls and the bottom 6 inches were 18 OFFICIAL USE ONLY