‘Intersex Fish Of The Lower Potomac’ Is Not A Reality Show. It’s A Reality.

Intersex smallmouth bassBack in 2003, a male smallmouth bass was caught in the south branch of the Potomac River that had both male and female parts – intersex. Since then, wildlife biologists have discovered that 50-100% of the fish in various tributaries leading into Chesapeake Bay have become intersex . Here’s a USGS explanation why fish become intersex:

“Intersex is one manifestation of endocrine disruption in fish. Endocrine disruption can result in adverse effects on the development of the brain and nervous system, the growth and function of the reproductive system, and the response to stressors in the environment. U.S. Geological Survey (USGS) scientists have documented the presence of endocrine disrupting contaminants in rivers and streams across the nation. Additionally, USGS scientists and others have demonstrated that exposure to endocrine-active contaminants can cause endocrine disruption, which can have ruinous impacts on fish populations.”

What’s causing the endocrine disruption is still a mystery. In addition to stormwater overflows loaded with sewage and pharmaceutical waste, pesticide pollution and manure with natural hormones from upstream farms are also considered a cause of the he-fish to he-she-fish transformations. There are currently two new bills in the Maryland House and Senate that would require farmers to better track what pesticides they’re using on their farms. [Washington Post]

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