North American freshwater fishes race to extinction

Aug 10, 2012

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 , 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 the Earth's freshwater fish diversity. At least 57 North American species and , 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 .

Extinctions in fishes are mostly caused by loss of habitat and the introduction of nonindigenous species. In North America, there are more 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.

Explore further: Seeds keep vital much longer when stored without oxygen

add to favorites email to friend print save as pdf

Related Stories

Bird species are saved from extinction

Aug 28, 2006

The first global audit of threatened species shows 16 species of birds nearly extinct in the mid-1990s have been saved, some increasing tenfold in number.

Recommended for you

Seeds keep vital much longer when stored without oxygen

32 minutes ago

If seed breeding companies, gene banks and the Svalbard Global Seed Vault on Spitsbergen should store plant seeds under oxygen-poor conditions, it would be possible to store them for much longer while still ...

Native species may be hindering fox control efforts

34 minutes ago

Native species interfering with ground distributed baits used to control red foxes in south west Western Australia may mean the baits are not available to the target species, a Murdoch University study has ...

Giant anteaters kill two hunters in Brazil

Jul 26, 2014

Giant anteaters in Brazil have killed two hunters in separate incidents, raising concerns about the animals' loss of habitat and the growing risk of dangerous encounters with people, researchers said.

Study indicates large raptors in Africa used for bushmeat

Jul 24, 2014

Bushmeat, the use of native animal species for food or commercial food sale, has been heavily documented to be a significant factor in the decline of many species of primates and other mammals. However, a new study indicates ...

User comments : 0