one-third the value reported by Jennings sockeye Salmon from Petersburg, Alaska, (1968) in 1964. reported by Jennings (1968) Bristol Bay, in 1967 and by Jenkins Alaska, salmon from Kotzebue, 5 Yet, the levels for sockeye and Chinook salmon from Alaska, (1968) fer chum in 1968 are of the order of 500 Pci . Fe/fmg Fe, for chum and ses or less than the levels in Pacific tuna from the northern hemisphere by a factor of more than two. Iron~-55 in salmon from Alaska and the Washington coast appeared to decrease from 1964 to 1967 more rapidly than expected from decreases in the rate of fallout +t ge (Jennings, . » was no Significant decrease in years 1967, 1968, tuna. 1968; 55 Jenkins et al., ws woe, 1968). There . Fe specific activity during the and 1969 in either Atlantic cod or Pacific Since the salmon were generally from areas of maximum rates ofca 55 2 ‘ Fe fallout in 1963 andaq 1964, * * 4 1 aL it is possible that the . 8 55 decrease was a relatively localized phenomenon and that the Fe levels in fish from the North Atlantic and from latitudes south of 40°N in the North Pacific approached equilibrium with the rate - 5.5 of fallout of Fe. boy eae atekeugh Lhe large variability of the data casts doubts on the validity of such arguments, nevertheless, they ere useful Tt is as working hypotheses. clear that latitudinal differences occur in the North Atlantic end thet at least hemispheric differences occur in the Folsom and Young (1965) sampled d stinct North Pacific and South Pacific populations of albacore Jes Pecific. (hunnus alalunga) in