Why it matters
Feminized fish
1st March 2008
Chemicals that mimic estrogen leading to fish declines
Ontario lakes: feminizing fish
Synthetic estrogen, excreted by women on the Pill into wastewater, disrupts the sexual development of fish, “feminizing” males and lowering the population’s fertility. Last year, Professor Karen Kidd of the University of New Brunswick reported that estrogen in one Northern Ontario lake caused the fathead minnow population to decline by 90 per cent in three years. Now, she has told the American Association for the Advancement of Science that the decline in small fish is affecting other species: Trout, which feed on minnows, declined by about 30 per cent.
“Feminized fish” are found in lakes and rivers all over the world, not only because of the birth control pill, but also because of a number of other chemicals – from pesticides to detergents – that mimic estrogen.
It’s not all bad news. Ms. Kidd says that once estrogen was no longer going into the lake, the minnow population, as well as that of other species, recovered in three years.
Published in The Green Report in The Globe and Mail
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