If current trends prevail, North American fish species will soon be going extinct at twice rate they are now. So finds scientists at the United States Geological Survey, in a study that will be published in BioScience this September.
But this latest doubling really isn't really so radical in the context of the last hundred years or so—the same study finds that over that period, from 1900-2010, the rate of fish extinction in North America rocketed to 877 times that found in the fossil record. We've been killing off fish with disastrous expediency for quite some time now.
From a preview of the study over at the USGS:
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.Get that? One species every 3 million years. We've certainly ratcheted that up some.
The study outlines some of the various ways that the fish are being pushed to extinction:
- "Natural causes of fish extinction are linked to transitions in landforms and continental watercourses over time, but many twentieth century extinctions were caused by dams, channelization of rivers, water pollution, and other human-induced factors."
- "The Alberca silverside was found only in the Alberca Caldera, Guanajuato, Mexico; it went extinct when the caldera temporarily dried up in August 2006."
- "Another cause of extinction can be a change in a fish's food chain, which is what may have happened to the harelip sucker, a really cool fish that used to live in seven states throughout the Ohio River basin," said Burkhead. "It was a snail-eating specialist with cleft lips that used to pluck snails off river bottoms and manipulate the snail in its mouth in order to suck out the snail's soft parts, perhaps making little popping sounds. Sadly, snails are highly sensitive to excessive sedimentation and in the late nineteenth century, large amounts of topsoil were washing into rivers along with sewage and industrial effluents from cities. This likely caused snails to decline, which may have been what drove the fish to extinction."
Overall, human activity is the major culprit here, which should surprise precisely nobody. Also unsurprising—that the rate of extinction will only climb as we continue to develop, pollute, and otherwise impact rivers, lakes, and other freshwater ecosystems. Hell, we almost certainly won't even notice as most of these species die out, casualties of runoff from industrial agriculture and waste flows from urban areas and other myriad forms of pollution.
But that's just how we roll in the Anthropocene—so long, fishes.