Tuna Fisning goes westward at about 15 to 18 nautical miles ver day. On approaching the Philippines this current sweeps northward and most of it @mters the region to the east of Formosa. However, these currents are not well defined during this season of the year and on approaching Janan are confused and variable. South of the Marshalls, there is a counter current setting to the east which, shifts with the season, mut may reach a velocity of 15 miles per day. This current never seems to get as far north as the northern islands of the Marshalis. Access to the southern tuna fishing areas in the region of the Solomons, Samoa and Gilbert Islands would not seem to be appreciably interfered with by the present danger area save in the case of the “ilbert Islands. Contamination of Fish. Tuna fish have been cavght in the northern Marshalls Following the first detonation but results are not yet available. Fish caught after the MIKE shot of IVY 2-1/2 to 3-1/2 miles from the crater 6 days after the shot gave the following results: 1. 2. Activity in whole fish (average) 25 po/gram Activity in Tissues(vet Weights) {a) Muscle = I76 jic/gram wet tissue (pe - microcurie) (>) Liver ~ Dyc/pram 7 (c) Gut ~ 34 ne/gram From considerations of current, the depth of mixing of surface water, the rate of decay of fission products and the decree to which fish in contaminated water tend to absorb fission products, I reached the conclusion that the probalility of significant contamination of fish outside the immediate test area is inconsequential and that in all likelihood we will be unable to detect these waters more than a few hundred miles away from the Marshall Islands, The attempt, of course, will be made to measure this contamination. John Cc. Director pugher, Hele Division of Slology and hedicine