Intersex Fish in the Sudbury

In recent decades, scientists have discovered that the presence of human hormones and hormonemimicking chemicals in rivers, lakes, and streams can affect the endocrine systems of fish. These chemicals can feminize male fish, masculinize female fish, impact reproduction, and potentially affect the population’s ability to survive. This working paper attempts to summarize the local findings of a large federal study titled: “Evidence of estrogenic endocrine disruption in smallmouth and largemouth bass inhabiting Northeast U.S. National Wildlife Refuge Waters: a reconnaissance study” (Iwanowicz et al., 2013). Other studies of endocrine disrupting chemicals in the Assabet River were carried out in 2009-13 by the U.S. Environmental Protection Agency (EPA) in collaboration with the U.S. Geological Survey (USGS), OARS, and UMass Amherst. These will be discussed in future Working Papers.