In the fossil record, one freshwater fish species goes extinct every 3 million years, but North America lost 39 species and 18 subspecies between 1898 and 2006. Based on current trends in threatened and endangered fish species, researchers estimate that an additional 53-86 species of freshwater fish may be extinct by the year 2050. Since the first assessment of extinct North American freshwater fishes in 1989, the number of extinct fishes increased by 25 percent.