Scientists say for the first time in U.S. and probably global history a fish identified as endangered has been shown to have recovered.
The population of shortnose sturgeon has increased by more than 400 percent in the Hudson River since the 1970s, Cornell University Assistant Professor Mark Bain and colleagues report.
However, researchers note shortnose sturgeon is still endangered in other rivers and will not necessarily be removed from the U.S. endangered species list.
During the past 100 years, 27 species of fish have died off in North America and four have become extinct. The U.S. government currently protects 149 fish species and subspecies and a total of 1,311 species.
"Endangered and threatened U.S. fish outnumber mammals, reptiles, birds, etcetera," said Bain. Since 1966, when the federal government started identifying threatened species, only 16, including the American alligator, American peregrine falcon and brown pelican, have recovered.
"Recovery is very rare," said Bain. "The nature of this species, its habitat and evidence for a large and secure population are an example of successful protected species management."
The study appeared online in the Jan. 24 edition of PLoS ONE.