Effects of Tritiated Water on the Embryonic Development of Two Marine Teleosts.

Artificially fertilized eggs of common flounder, Paralichthys olivaceus and a species of puffer, Fugu niphobles were reared until hatching in tritiated sea water of various concentra tions. No significant difference in their hatchability was observed between control and triti ated water groups of 10-8 to 10-2 Ci/l. However, a decrease in puffer egg hatchability was observed in tritiated water of very high concentrations, i.e., 1 and 10 Ci/l . Absorbed radiation dose was calculated to be 2160 rad in 180 hours for the 1 Ci/l group and 15600 rad in 130 hours for the 10 Ci/1 group. The hatched larvae of the 10 Ci/1 group were rather inactive, lying on the bottom of the tank, whereas the control larvae swam actively. Compared with control larvae, the 10 Ci/1 larvae developed smaller stumpy-shaped bodies with swollen abdomens. Although the eye diameter of the 10 Ci/l larvae was found to be only about 57 per cent that of the controls, the body weights of both groups were nearly equal, possibly due to the larger amount of residual yolk in the 10 Ci/1 larvae. These findings indicate that the morphological development of embryos reared in tritiated water of high concentration is retarded.