Gender Line Blurred in Fish
This release can be found in the USGS Newsroom at:
Contamination in U.S. Private Wells.
Gender Line Blurred in Fish
Male smallmouth and largemouth bass with female characteristics have been
discovered in surprisingly high numbers in eight of nine river basins
throughout the United States. In some rivers, more than 70 percent of male
bass were “feminized.” Scientists suspect the cause of this condition,
which leads to immature female eggs in male fish and poorer reproduction,
may be linked to substances that have hormonal effects. Endocrine-active
compounds like pharmaceuticals, pesticides and household items are possible
causes, though some intersex fish were found at sites with no obvious
sources of this type of contamination. Because this study didn’t examine
the causes for this condition, more information is needed about the genetic
and environmental factors that might be responsible, as well as the number
and kinds of fish affected. Check out the USGS Newsroom for more
information, or contact Jo Ellen Hinck at jhinck@usgs.gov or (573)
876-1808.