Salmon are becoming river "ghosts" as brutal droughts and violent floods cause unprecedented losses on their treacherous journey to the Pacific Ocean, scientists say. A study led by the University of Essex; NOAA Fisheries; University of California, Davis; and Cramer Fish Sciences has found that youn g Californian Chinook salmon face a deadly double threat from extreme weather and the destruction of historical wetland habitats they rely on. ...read more read less