From inspection of Table 2 the fellowing conclusions are made. There were measurable amounts of radioactivity in all the pre-shot samples, especially those from Bogombogo. For similar areas, the post shot samples were more radioactive than the pre-test samples by 200-300 times. The post shot samples from Igurin were higher than those at Rigili, Aaraan- biru and Runit, which were closer to the shot island. Usually the catch in the fine~meshed net was considerably more radioactive than the catch from a coarser-meshed net for paired hauls from the same station, especially in the post shot samples. Some radioactivity was also found in the plankton preser- vative. The activity of the preservative from the Bogallua collection that was filtered through No. 42 Whatman paper was 10,000 dfm/ec as compared to 11,000 d/m/ce for the unfiltered sample. The plankton for the same sample was 100 times greater (1,100,000 a/m/g wet). The activity of the preservative sug- gests that some radioactive isotopes associated with the plank- ton are partly soluble in a 4 percent formalin solution or that some of the adsorbed particles are washed off the organisms. 4.3 Algae The algae collections included five species of blue-green algae, 14 species of green, 3 species of brown, and 7 species of red algae. A cheek list of species collected for assay is given in the Appendix. Anelysis by Area. Because of the paucity of samples and non-randomness of sampling, the best evaluation of the data - 25 -