The four circles represent locations where the California North Coast Regional Water Quality Control Board, in 2010 and 2013, found “acute (and) chronic reproductive toxicity” in streams feeding the Smith River estuary. The glowing circle is at the mouth of Rowdy Creek, one of the Smith River’s two most important salmon streams, where the state discovered the “acute” toxicity, meaning that invertebrates that make up the basis of the salmonid food chain not only cannot reproduce, but cannot survive in this water.