USGS - 90% Of Pee Dee River Bass Intersex; 100% Of Bass In Potomac

[hatrack]

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The small mouth is also a fish of special value to researchers who suspect it may tell us something alarming about our water. In Columbia, Mo., the U.S. Geological Survey is keeping smallies in some artificial ponds, investigating why so many males are showing female characteristics.

"Because it's male, you're seeing sperm here and here," said USGS Dianna Papoulias while examining a fish. "But oddly, you're also seeing eggs. Small, undeveloped eggs." "It is an abnormality," she said. "In bass we would not expect to see eggs in a male."

Abnormal - but increasingly common. In the upper Mississippi River where Loren Waalkens fishes, more than 70 percent of the male smallmouth bass had female characteristics. In South Carolina's Peedee River, the ratio was even higher - 9 out of 10. And in one section of the Potomac River near Washington, every smallmouth bass had the same condition.

In fact, a recent USGS study found the phenomenon in virtually every watershed in the country. And it's and not just bass. Some carp, catfish and sturgeon have the same odd make-up.

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http://www.cbsnews.com/stories/2009/11/25/eveningnews/main5778106.shtml