- Radioactive Coconut Crabs a = eee = eT n wae af One of the few anomalies which has resulted from the radioactive fallout persists even today. The coconut crabs of Rongelap Atoll, called birgus latro, or, the robber crab, have retained significant amounts of radioactivity to this day. This is in part due to these crabs feeding on material which contains long lived radioactive isotopes like strontium and cesium. The cesium 137 tends to concentrate in the muscle of the crab, while the strontium concentrates in the carapace, or shell (in effect, the strontium locates in the calcium-rich shell, just as it does in the bones of human beings. The shell of the crab is actually the outer, or ectoskeleton, the equivalent of the internal human skeleton. What has made this creature become a dietary item forbidden to the Rongelapese is the crabs' habit of eating their own shells which they have sloughed off, or discarded periodically. In this manner, they manage to retain a relatively high amount of radioactivity in the shells and thus the Rongelapese have been told not to eat them. During the 1972 survey, Dr. Conard brought the Rongelapese what appeared to be good news concerning this crab, rightly considered by the people to be a delicacy. He told them that the crabs from Rongelap and a neighboring island could now be eaten at a rate of one per person per day. The crabs from other islands on the atoll, he indicated, would still remain on the restricted list until radiological analyses showed that they were safe to eat. The 1972 Annual Survey of Rongelap and Utirik The events leading up to the delay of the regular 1972 survey which normally would have taken place in March of that year, and leading to the ™ 121