Earth In Transition
The rate at which fish are going extinct in North American rivers and lakes is rising dangerously and may soon double again, according to a study to be published in September by the United States Geological Service.
The fossil record shows that before the 19th century, freshwater fish were going extinct at the rate of one species every three million years. But in the last hundred years, that has changed dramatically.
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.
What’s causing this dramatic shift? Mostly it’s because water is drying up,
we’re building more dams, there’s more water pollution, and we’re affecting
the whole food chain. Basically, the study points at human activity as the
major reason as to why there has been a significant increase in the rate of
extinction of the fish and it predicts that the rate will increase as we
continue to pollute the environment the fish live in.
Last year, British scientists found that freshwater fish are the most endangered animals on the planet. Dr. William Darwall of the International Union for the Conservation of Nature (IUCN) told the Daily Telegraph that across Europe 38 percent of freshwater fish are now threatened.
Of the 5,685 species that have been assessed, 36 per cent of them are
Compared to mammals, where 21 per cent are threatened, and birds, where 12 per cent are threatened, it is clear that fresh water ecosystems are among the most threatened in the world.
Sadly, it is also not going to get any better as human need for fresh water, power and food continues to grown and we exploit freshwater environments for these resources.
The IUCN’s Red List also shows that in Africa around 28 per cent of freshwater fish are threatened, largely because of overfishing. And the situation is equally bad in China and South Asia. The dams along the Mekong river have already caused the giant catfish who once thrived there to have dwindled to just 250 individuals – and eight more dams are planned along the river.
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