Gender Bender Fish Step Out In Tokyo

Japanese magazine Playboy Weekly reported this week that numerous breeds of fish in Tokyo Bay are adopting feminine genetic traits, apparently because of the presence of the female hormone estrogen entering the water via the sewage system.

"Ovaries were found in some of the male fish," said a Tokyo council spokesman.

"We think the influence of female hormones in women's urine passing into the sea from the sewage treatment plant has a lot to do with the feminisation of fish." (Mainichi)

The story appeared almost three years after British scientist Professor Charles Tyler announced that up to a third of male fish in lowland British rivers had also recently changed sex because of estrogen, a phenomenon which has also been identified amongst Chinook salmon in Canada.
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