North American freshwater fish diversity is in decline:
North American freshwater fishes race to extinction, EurekAlert: 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 the 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. ... 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.