Impact of the Great East Japan Earthquake on Reproductive Biology of the Freshwater Teleost Bluegill Lepomis macrochirus

ABSTRACT

Soon after the Great East Japan Earthquake and the subsequent accident at the Fukushima Daiichi nuclear power plant, we studied the reproductive biology of freshwater teleost bluegill (Lepomis macrochirus) in a pond in the city of Iwaki, Fukushima Prefecture, about 50 km south of the nuclear power plant. The breeding period of the bluegill was abbreviated and the frequency of spawning decreased. The radiation air dose rate and level of radioactivity in the fish were less than would be expected to trigger behavioural alterations or to suppress reproduction. The occurrence of aftershocks and two episodes of torrential rain is the likely reason for changes in the reproductive behaviour of bluegill in the pond. These results suggest that our observations can be explained by a combination of natural disasters, rather than the effects of nuclear radiation.

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