-20-
that of other fish tissues.
Goatfish viscera (Fig. 7), on the
other hand, declines similarly to that of sea cucumber gut,
the liver of an omnivore, and to some degree, algae.
feed largely on brachyuran crabs, which,
dead fish, etc.,
degree,
Goatfish
in turn, feed on algae,
so that the diet of goatfish is, to a certain
comparable to that of omnivorous fishes.
Comparison of Decline with Decay of Radioactivity
Figures 7 through 10 show certain marked differences between decline and decay of radioactivity in the same tissues
for both goatfish and mullet.
In goatfish the differences are
evident in the first 100 days after shot, while in mullet the
differences are greatest for the first 150 to 200 days.
Vari-
ations due to sampling and other causes, which have been discussed in a previous section, might explain some of the differ-
ences.
Also they might be due to the differential affinity of
various species for shorter-lived isotopes.
In goatfish the
radiation varies to around 50 to 170 uc/kg for liver, about 20
to 50 uc/kg for bone and 3 to 7 uc/kg for muscle.
Similarities in the decay curves are shown in Figures 7,
8, 9, 10, and 11.
For example, liver decay in goatfish (Fig.8)
is similar to that of mullet liver after 100 days; muscle decay
in goatfish is similar to surgeonfish liver and surgeonfish bone
after 200 days; while bone decay of goatfish is similar to bone
decay of mullet and surgeonfish after 100 to 250 days.
Dissimi-
larities in the decay curves appear to be greatest during the
first 100 to 200 days after the shot,
the curves tending to