observed.
Although it is recognized that observations of
dying fish may not be apparent because of the removal by predators of fish in a weakened condition,
it is believed that
the amount of radioactivity in water necessary to kill fish
directly would have to be greater than the amount of radioactivity that has occurred in the water in the vicinity of
Bikini-Eniwetok.
If fish survive exposure to ionizing radiations there
still may be non-lethal effects in the form of pathological
or genetic damage from either external or internal emitters.
Again referring to the Bikini-Eniwetok area,
thousands of
fish have been examined for gross pathological and morphological changes but no obvious changes have been observed
(Welander 1959).
However,
Gorbman and James
(1959)
found
upon examining microscopically the thyroids of reef fish from
an area close to a test site that the damage to the thyroid
ranged from zero to 100 per cent.
thyroid was damaged,
In those fish in which the
the fish upon superficial examination
otherwise appeared to be normal.
The cause of damage to the
thyroids was undoubtedly radioisotopes of iodine,
emitters,
as internal
that are present in relatively great abundance immedi-
ately after the detonation of a nuclear device.
As the half life