Growth rate measurements in gamma irradiated catfish.

The effect of whole body gamma irradiation at the low exposure levels of 100, 200 and 400 r has been studied on the rate of growth of both juvenile and adult males and females of Clarias lazera. Irradiation causes, in general, significant retardation in rate of increase in length of growing fish. Such retardation is especially marked in adult females. Irradiation causes also diminution in the percentage increase in weight of adults especially the females. In juvenile fish, radiation exposure at the levels of 100 and 200 r accelerates the rate of increase in weight while the higher exposure level of 400 r results in a significant retardation. The exposure level of 100 r increases the ratio weight/length only in juveniles. Exposure levels of 200 and 400 r decrease such a ratio. The results obtained are explained in correlation with the general knowledge of biological radiation syndrome and discussed in view of the relevant literature.