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North American Freshwater Fishes Race to Extinction
date:Aug 14, 2012
e found nowhere else.


Estimating the number of extinctions relies on scrutiny of historical records and careful estimation procedures, since the last populations of a species are often recognized as such only in hindsightthere is typically a lag of several years from the last observation of a species and its estimated year of extinction. Estimates are complicated by the fact that, on average, 6.7 new species are discovered each year, and occasionally a species thought to have gone extinct is r

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