Biologists Try to Save Rare Trout ... by Poisoning a River Controversial plan designed to flush out other species from creek By Kevin Spak, Newser Staff Posted Sep 5, 2013 10:32 AM CDT 18 comments Comments Dead fish are seen in this file image. (Shutterstock) (Newser) – California fisheries officials pumped an 11-mile stream full of poison yesterday, killing all the fish in it—in what, believe it or not, is a conservation plan. State officials are trying to preserve the Paiute cutthroat trout, the rarest trout in the world, the LA Times explains. It's native to Silver King Creek, but had been pushed out by invasive trout species. The poison, which has now been neutralized, was designed to kill off the stream's rainbow and golden trout, and make way for the Paiute. It's a controversial move. "I have a basic philosophical objection to anyone polluting a natural waterway," says the supervisor of Alpine County, arguing that officials should have used more expensive but less hazardous methods, like electroshock. The poison used, rotenone, is banned in US coastal waters, and entirely in Europe. But officials insist it's safe. "Rotenone is as close to a silver bullet as anything we have," one fish biologist says. "It hardly impacts anything but fish." Click here for the story of a rotenone kill that didn't quite go according to plan.