In science news this week: Clips and codes: How many Central Valley salmon come from hatcheries?  “Every year, hundreds of thousands of adult Chinook salmon race upstream to their spawning grounds in the tributaries and mainstems of the Sacramento and San Joaquin rivers. But sometimes, salmon get mixed up about which river they should return to for spawning. Following the 2016 fall-run migration season, we shared our surprising results of adult salmon monitoring on the Stanislaus and Tuolumne rivers. Despite … Continue reading SCIENCE NEWS: How many Central Valley salmon come from hatcheries?; Pacific Northwest woodlands less vulnerable to drought; New study explores ecosystem stability; US groundwater in peril; and more …