-14-
The levels of specific radionuclides in the species other
than yellowfin tuna were similar to the levels of radioactivity
in the yellowfin tuna
(Tables 4, 5, and 6).
Levels of radio-
activity for most radionuclides usually were lower in all
species and tissues than the potassium-40 levels.
yellowfin,
As in the
the exceptions occurred in some tissues containing
radioiodine.
The samples with detectable amounts of radioiodine
constitute about seven per cent of the total number of samples.
Differences in levels of radioactivity in the tissues of different
species were slight and variable.
However,
the number of samples
with detectable levels of specific radionuclides was greatest
in the liver tissue and least in the light muscle tissue.
The strontium-90 levels in eight fish tissue samples analyzed were also very low,
ranging from no significant data (nsd)
to 0.053 picocuries per gram wet weight.
in Table 7.
The data are summarized
The strontium values appear to be slightly higher
than those reported by R. Fukai, H.
Suzuki,
and K. Watanabe
(1962).
Plankton
Samples of plankton were taken at 86 stations.
containing large organisms were subdivided into fish,
jellyfish,
salps,
The samples
crustacea,
Pyrosoma and smaller plankton which have been
called “remainders."
If no large organisms were found, the
plankton organisms were not separated and the sample was labelled