Coho Salmon

Each fall, thousands of coho salmon flock to Northwest rivers to spawn. But many never get the chance, [blank] in big cities like Seattle. "And in some of these urban [blank] , up to 90 percent of the females were dying before they spawned, which is not a good thing for a population long term." Julien Spromberg is a toxicologist affiliated with the Northwest Fisheries Science Center. Researchers suspected these deaths were partly a matter of bad timing. The fish often reach streams during the first showers of the rainy season, which [blank] chemicals from roads and parking lots into the water. Now, Spromberg and her colleagues have produced the first direct evidence that this runoff kills coho salmon. Their study is in the Journal of Applied Ecology. Researchers found that fish exposed to stormwater from Seattle-area highways quickly grew sick and died. Surprisingly, though, the salmon did not seem to mind [blank] a dip in a cocktail of common road pollutants, including hydrocarbons and metals. That detail suggests the killer ingredient in the runoff may be a different kind of chemical or a lethal combination of several compounds. "There's a whole lot of stuff here that we haven't been able to measure or don't have the capabilities of measuring at this point. "However, Spromberg says there's a way to help the fish even before scientists hunt down the culprit. Her team also [blank] that filtering runoff through just a few feet of soil made stored water safe for salmon. Cities can implement this simple form of clean water technology by building more systems, including roadside rain gardens, to collect runoff from paved areas and pass it through soil before it enters urban waterways. Literally quick and dirty [blank] .