Intersex Fish Found In Protected Waters

Researchers are finding that even in some of the cleanest waters in the U.S., pollution appears to be altering the sex functions of fish and making them intersex, a condition that hinders reproduction.

Missisquoi National Wildlife Refuge, near the U.S.-Canada border, is among the “most productive and pristine wetland ecosystems” in the Northeast. Yet even there, researchers are seeing troubling abnormalities in fish populations, and it is raising concerns about water quality across the country.

The problem at hand: endocrine disruption. In fish populations, this refers to “the presence of female eggs in male testes indicates some kind of hormonal confusion,” National Geographic reported.

In a new study, “scientists from the U.S. Fish and Wildlife Service and the U.S. Geological Survey studied fish in 19 national wildlife refuges in the U.S. Northeast, including Missisquoi,” the report said.

The researchers published their findings this month in the journal Ecotoxicology and Environmental Safety.

“Their conclusion: An astonishing 60 to 100 percent of all the male smallmouth bass they examined had female egg cells growing in their testes,” National Geographic reported.

Researchers had made similar findings before, as Water Online has previously reported. So why does this new research matter?

“Over the past decade, feminized male fish have been discovered in 37 species in lakes and rivers throughout North America, Europe, and other parts of the world. Experts say the new discovery in protected wildlife refuges is worrisome because it suggests that pollution may be even more pervasive than previously thought,” National Geographic reported.

Luke Iwanowicz, a U.S. Geological Survey researcher who led the study, weighed in per National Geographic.

“There are no truly untouched areas. I think the take away here is that everything we do, everything we use or put on the land, ends up in the water at some point,” he said.

“When fish are getting intersex, it’s probably a good indication that something is wrong in the environment,” added Vicki Blazer, another researcher with the U.S. Geological Survey.

For similar stories, visit Water Online’s Source Water Contamination Solutions Center.