71
per unit volume of forage space than in the pelagic division.
The relatively high concentration of gamma radioactivity
in stomach and liver
compared to muscle and bone is probably
due to the association of the transition
systems in living organisms.
Those
elements with enzyme
tissues sustaining
the
highest rates of enzyme catalyzed metabolism would be expected
to show the highest concentrations of transition elements,
group to which the principal gamma emitters
in the
the
marine
environment belong.
For determining differences in the general levels of
radioactivity in the lagoon near Rongelap and Kabelle Islands,
fish tissues with a slower turnover and more constant meta~-
bolic demand for the radioactive elements should be more useful than tissues with rapid turnover and fluctuating metabolic
demand.
G.
I.
tract tissues,
for example,
would be responsive
to immediate metabolic requirements and to local fluctuations
in the external environment.
other hand,
Bone and muscle tissues,
on the
tend toward a steady state with respect to meta-
bolic demand and consequently to turnover and would not be as
sensitive to short~term fluctuations in the availability and
uptake of radiomaterials from the external environment.
Bone and muscle tissues of carnivorous fish from Kabelle
Island showed consistently higher. levels of gamma radioactivity