Male fish in two of North Jersey’s most protected areas have developed female sexual characteristics, suggesting parts of the Wallkill River in Sussex County and the Great Swamp in Morris County are contaminated with chemicals that throw hormone systems radically off.

Immature eggs were found growing in the testes of male bass caught at both national wildlife refuges, according to a recently published report by the U.S. Geological Survey. The reason the fish are developing female reproductive traits is unknown, but the research team says the bass were likely exposed to chemicals found in everything from agricultural runoff to hormone-based pharmaceuticals that cannot be filtered by sewage treatment plants.


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