Quirks & Quarks

The Birth Control Pill is Harming Fish

Residue from birth control pills in sewage can cause populations of a minnow species to crash, affecting the species that prey on them....
Fathead Minnow - copyright Rankin1958 cc-by-sa-3.0
Residue from birth control pills in sewage can cause populations of a minnow species to crash, affecting the species that prey on them.We have known for years now that many pharmaceuticals make their way into our waterways, through residues in urine, or by disposal of unused drugs down our toilets.  The consequences are often detrimental to aquatic wildlife.  One well known consequence is the feminization of male fish, which has a negative impact on reproduction. This is attributed to traces of the sex hormone estrogen making its way through sewage filtration facilities into rivers and lakes.  Dr. Karen Kidd, a Canada Research Chair and Professor of Biology at the University of New Brunswick in Saint John has studied this phenomenon in the fathead minnow in an experimental lake in Northern Ontario.  The subsequent crash of the fathead minnow population upset the balance of the entire ecosystem.  This included a sharp decline in the trout population, which prey on the minnow.  Researchers were surprised that the minnow population was able to recover as estrogen levels declined.

Related Links

  • Paper in The Proceedings of the Royal Society: Biological Sciences
  • University of New Brunswick release
  • The Guardian news story
  • CBC News story

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