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Conclusions
Blological decline of radioactivity in the fishes of Belle
Island, Eniwetok Atoll, is generally similar in 4ll species.
Differences which are evident may be attributed to differences
in feeding habits and, these differences, which appear greatest
during the first 100 to 200 days after shot, may be attributed
to differences in the uptake and retention of the short-lived
isotopes.
The decline of the radioactivity in omnivorous fishes
is more rapid than that in carnivorous fishes so that 200 days
after shot the amount of radioactivity in the two types of fish
appears to be quite similar.
It might be postulated that omni-
vorous fishes ingest food which contains comparatively greater
amounts of the shorter-lived fsotopes than the food of carni-
vorous fishes.
The decay of radioactivity in the tissues of fish from
Belle Island
also differs during the first 100 days after the
shot, reflecting, to some degree, the unstable ecological condi-
tions prevailing in that region at the time.
The relationship of the amounts of radioactivity retained
in each of the five tissues examined prevails more or less consistently and substantiates findings of previous investigations.
The greatest per-gram concentration of radioactive materials
occurs in the alimentary tract with the liver, skin, bone and
muscle having successively lesser amounts.
The greatest vari-
ation from this pattern appears during the first few weeks after
shot.