The effects of ionizing radiation on the reproductive capacity of adult Penaeus (Marsupenaeus) japonicus (Bate)

The reproductive capacity of adult Penaeus (Marsupenaeus) japonicus (Bate) was assessed after exposure to ionizing gamma radiation from a cobalt-60 source. Males and females were each exposed to 0, 10 and 20 Gray (Gy) of ionizing radiation (IR) and reciprocally crossed to give nine mating combinations. Fecundity and hatch rate of resulting spawnings were used as measures of reproductive capacity. IR significantly (P < 0.05) reduced the fecundity of females when treated at 20 Gy compared to 0 and 10 Gy. The mean number of eggs per female for the 0 and 10 Gy crosses was 24,280 ± 4680 and 47,000 ± 9670 respectively, compared to 11,600 ± 6840 for the 20 Gy crosses. Hatch rates from spawnings of females crossed with irradiated males were significantly lower (P < 0.05) than for females crossed with non-irradiated males. The mean hatch rate of spawnings from females crossed with 0 Gy males was 64.02 ± 8.85% compared to 20.77 ± 5.46% for 10 Gy and 11.95 ± 6.13% for 20 Gy male crosses. These results indicate that IR has a negative impact on the reproductive capacity of females at 20 Gy, and males at 10 and 20 Gy. However, IR was not found to be 100% effective at preventing the production of viable offspring using the reported treatment regimes.