Chemicals in the Chesapeake Bay watershed and other locations could be causing fish to take on another gender.
U.S. Geological Survey biologist Vicki Blazer noticed male fish with eggs in their testes, the Washington Post reported. The phenomenon was observed in smallmouth bass and white sucker fish across 16 sites. At one polluted site in the Susquehanna 100 percent of male fish were intersexes, meaning of both genders.
"I did not expect to find it quite as widespread," Blazer told the Post.
Past studies on the water have revealed herbicides and veterinary pharmaceuticals. These chemicals have the ability to disrupt the endocrine system of creatures exposed to them. They are introduced to the water through farms and sewage runoff. In urban areas products containing estrogen are often flushed down drains, contaminating the water.
"We found female germ cells in the testes of 82 percent to 100 percent of the male smallmouth bass and in 23 percent of the males from . . . largemouth bass," the U.S. Fish and Wildlife Service said, the Post reported.
Researchers have not determined the exact chemical cocktail that causes this sex change because farmers are not legally required to immediately report which chemicals they are using. Democrats in the Maryland House and Senate sponsored a pair of bills that would require growers to submit a list of the insecticides and herbicides they use to the state.
Reporting the pesticides used on farms could provide a "trove of data" scientists could use to determine the effect of them on both human and animal health as well as pinpoint chemical "hot spots." But the requirement was amended after the Department of Agriculture said it would cost $1.5 million for new employees to collect and record this data. Instead the lawmakers passed legislation creating a fund that will one day pay for the mandatory reporting.
"[The fish are] an indicator that something else is really wrong," Blazer said. "What are these things doing to the natural environment? If we find these things in wild organisms, there's a good chance they're also affecting people."
