Scientists have found more intersex fish in Maryland, this time on the Eastern Shore, and their research suggests one possible source of the gender-bending condition could be the poultry manure that is widely used there to fertilize croplands.
Six lakes and ponds on the Delmarva Peninsula sampled over the past two years have yielded male largemouth bass carrying eggs, according to University of Maryland scientists. Those are the first intersex fish reported there, though researchers found the condition several years ago in smallmouth bass in the Potomac and its tributaries, and recently found it in smallmouth bass in the Susquehanna.
Intersex fish are a concern, scientists say, because they could be indicators of contaminants in the water, affecting their growth and reproduction.
The intersex condition in the Shore fish is not as severe as it is among fish from the Potomac or Susquehanna, the researchers said, but it appears to be widespread, at least in largemouth bass in the peninsula's lakes and ponds.
"We find it in every lake that we look," said Daniel J. Fisher, senior research scientist at UM's Wye Research and Education Center in Queenstown. "We found fish with intersex in all of the lakes, and the percentage
ranged from 33 percent of fish we sampled to 100 percent."
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