Changing Fish in Northland Waters
Duluth, MN (NNCNOW.com) -- There's something strange going on in the waters of the Northland... Fish are changing...not just one type of fish but almost all kinds, including the most popular game fish, like walleye and bass.
When we first reported on this phenomenon in 2002 concerns were just emerging.
Now, ten years later, scientists are beginning to call it a significant threat.
Walleye cakes, walleye bites, walleye sandwich...it's a popular delicacy in restaurants around the northland.
It's also a multi-million dollar industry, attracting hundreds of thousands of anglers to the Northland's beautiful lakes year round.
We take it for granted that we'll be able to fish forever...but scientists have uncovered a major threat to the reproductive abilities of many kinds of fish.
"Changes in, for example, the external characteristics of males where they start to resemble females," said Dr. Gary Ankley of the U.S. EPA Lab in Duluth.
"The small mouth bass and large mouth are sensitive to fish feminization. We're seeing lots of symptoms in these species," said Dr. Pat Schoff of the UMD NRRI.
Fish changing genders? It's a frightening phenomenon that's happening around the world. Scientists are diligently trying to figure out what's causing the problem. Their studies show a feminized male fish suffers a reduced reproductive ability of at least 76-percent and more and more they're finding fish that can't reproduce at all.
"Actually caused some fish populations to go extinct," said Dr. Ankley.
Duluth has some of the leading scientific research going on at UMD's Natural Resource Research Institute and at the Federal Environmental Protection Agency lab.
"There's only a few labs in the world that can do this very effectively when we deal with these very potent chemicals," said Dr. Ankley.
It's chemicals that scientists believe are the leading culprits in causing fish feminization.
"There's a number of chemicals that can act as what we call estrogens," said Dr. Ankley.
Literally thousands of chemicals make their way into our waterways every day. Things like birth control pills and agricultural run-off carry powerful estrogens that scientists believe may be bending the genders of fish.
"We can see everything from testicular tissue that is growing like an ovary. Or some fish have one teste and one ovary," said Dr. Schoff.
"The male testes actually has eggs in it," Dr. Ankley said.
The scientists know when they expose fish in the lab to estrogenic compounds they see nearly complete transformations from one gender to another and they know its damaging fish populations.
"There's lower rates of reproduction or even no reproduction," Dr. Schoff said.
Lab exposure is controlled but what the scientists don't know is what other chemicals, and in what amounts, are contributing to the problem in nature.
"It turns out there are chemicals that can mimic natural estrogens and when you expose males to these chemicals they can start to achieve these female characteristics," Dr. Ankley said.
"There's probably 5 to 8,000 different medications that are used and could enter the environment."
Even things as common as Ibuprofen may be contributing to the problem.
So we know the chemicals we use daily are a big part of the problem raising the question what can be done about it.
Scientists say it's extremely complicated. First they need to know exactly what chemicals are causing the problem and how they're getting into the water...and then they need to know if it's even possible get rid of them...and at what cost in financial and human terms.
As scientists around the world continue to study the spreading fish feminization impact they're turning to the public with some suggestions for what each of us can do to help.
Barbara will take a look at that as we continue our special investigation Tuesday night.