Changing Fish in Northland Waters: Part Two

By KBJR News 1

February 20, 2013 Updated Feb 20, 2013 at 11:30 AM CDT

Duluth, MN ( - Across the world scientists are researching a troubling problem. Male fish are changing genders making reproduction difficult if not impossible.

Scientists are rushing to figure out what's in the water that's causing the fish phenomenon and whether the impact could eventually spread to people.

The Western Lake Superior Sanitary District is known as a model of excellence across the country.

"As a community we work together to protect and preserve the natural resources that are so important to public health, our economy and our quality of life," said Marianne Bohren, executive director of WLSSD.

But despite having among the best water treatment systems possible something is getting into the water that is damaging fish...not just in the Northland but throughout the world.

Fish are changing genders. More and more male fish are showing female characteristics.

"We can see everything from testicular tissue that is growing like an ovary. Or some fish have one teste and one ovary," Dr. Pat Schoff with NRRI said.

Scientists say it's almost certainly a variety of chemicals that are causing the fish genders to change and while they don't know exactly what chemicals they strongly suspect that estrogenic compounds such as what's in birth control and estrogen replacement therapies are part of the problem.

"It's an example of the kinds of things that enter the environment in very small quantities but could affect, unintentionally, these non-target species," said Dr. Gary Ankley with EPA Lab Duluth.

While researchers have found feminized fish in more abundance closer to more densely populated areas, they are finding them even in what we consider the pristine lakes of the Boundary Waters.

"So it's really more common to find them than not find them," said Dr. Ankley. "So it's really a problem or issue that's very widespread."

Scientists know it's impacting fish reproduction.

"There's lower rates of reproduction or even no reproduction," said Schoff.

What they don't know is what, if any, impact these chemicals in the water, could eventually have on humans and other wildlife.

"It would be very surprising that the effects we're seeing on species in wildlife are not, somehow or other, translated into effects on humans," said Schoff.

As the scientists work to identify solutions they say each of us can play a role in mitigating the problem beginning with safely disposing of unused prescription drugs.

"When medications are flushed down the drain we now know they are not always completely removed from the water in the water treatment process, and those medications can end up in the aquatic environment, said Gina Temple-Rhodes with WLSSD.

When you dump something in your toilet or out in your yard or pour oil out on the street you don't realize that hits the waterways.

"Now that's not going to fix all the problems by any means but it's a small thing that I think people can do to help control what's entering the environment," said Andrew Frielund with the Twin Ports Walleye Asssociation.

The Duluth scientists are in regular communication with scientists around the globe to share information on what they're learning about the feminization of fish.
