flanerie.org

[found on Ananova]
Efforts to save a rare fish suffered a setback when scientists realised they'd been restocking rivers and lakes with the wrong species.

Researchers at the University of Colorado have been trying to restore the cutthroat trout, Colorado's official state fish, to its native habitat since the early 1970s.

They described the blow to the expensive, decades-long effort as a "setback", reports the Rocky Mountain News.

"This was a very surprising result," said Jessica Metcalf, a researcher at CU who led the study. "It's not at all what we expected."

The greenback cutthroat, named for the brilliant crimson slashes behind its jaw, was named Colorado's state fish in 1994.

It had been declared endangered in 1973 when the scheme was launched to restore the species using sperm and eggs from what were believed to be nine relic populations.

However, using DNA analysis, researchers recently found that five of those nine relic populations weren't greenback cutthroats at all, but Colorado River cutthroats.

Bruce Rosenlund of the U.S. Fish and Wildlife Service, played down the discovery and said only DNA technology could tell the difference between the two species.

"Our feeling for a long time has been that they were very, very closely related and indistinguishable... other than the fact that one's on the east side of the Continental Divide and one's on the west side," he said.