Science News
from research organizations

North American freshwater fishes race to extinction: Rate of loss of species exceeds that of terrestrial animals

Date:
August 10, 2012
Source:
American Institute of Biological Sciences
Summary:
The rate of extinction of freshwater fishes in North America is estimated to be 877 times the historical background rate. Thirty-nine species have gone extinct since the end of the 19th Century. Between 53 and 86 species are likely to have gone extinct by 2050, according to new estimates.
Share:
       
FULL STORY

North American freshwater fishes are going extinct at an alarming rate compared with other species, according to an article in the September issue of BioScience. The rate of extinctions increased noticeably after 1950, although it has leveled off in the past decade. The number of extinct species has grown by 25 percent since 1989.

The article, by Noel M. Burkhead of the US Geological Survey, examines North American freshwater fish extinctions from the end of the 19th Century to 2010, when there were 1213 species in the continent, or about 9 percent of Earth's freshwater fish diversity. At least 57 North American species and subspecies, and 3 unique populations, have gone extinct since 1898, about 3.2 percent of the total. Freshwater species generally are known to suffer higher rates of extinction than terrestrial vertebrates.

Extinctions in fishes are mostly caused by loss of habitat and the introduction of nonindigenous species. In North America, there are more freshwater fish species in a typical drainage to the east of the Great Continental Divide than to the west, where a greater proportion of species have gone extinct or are 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 hindsight -- there 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 "rediscovered." Nonetheless, Burkhead concludes that between 53 and 86 species of North American freshwater fishes are likely to have gone extinct by 2050, and that the rate of extinction is now at least 877 times the background extinction rate over geological time.


Story Source:

The above post is reprinted from materials provided by American Institute of Biological Sciences. Note: Materials may be edited for content and length.


Journal Reference:

  1. Noel M. Burkhead. Extinction Rates in North American Freshwater Fishes, 1900-2010. BioScience, September 2012 (in press)

Cite This Page:

American Institute of Biological Sciences. "North American freshwater fishes race to extinction: Rate of loss of species exceeds that of terrestrial animals." ScienceDaily. ScienceDaily, 10 August 2012. <www.sciencedaily.com/releases/2012/08/120810083716.htm>.
American Institute of Biological Sciences. (2012, August 10). North American freshwater fishes race to extinction: Rate of loss of species exceeds that of terrestrial animals. ScienceDaily. Retrieved July 4, 2015 from www.sciencedaily.com/releases/2012/08/120810083716.htm
American Institute of Biological Sciences. "North American freshwater fishes race to extinction: Rate of loss of species exceeds that of terrestrial animals." ScienceDaily. www.sciencedaily.com/releases/2012/08/120810083716.htm (accessed July 4, 2015).

Share This Page: