New paths to survival for endangered winter run Chinook salmon
Jan 7, 2018 at 5:00pm
by Anna Sturrock and Corey Phillis, UC Davis Center for Watershed Sciences
Many Californians have seen headlines about endangered Sacramento River Winter Run Chinook salmon (“winter run”) on the “brink of extinction.” But not many people know exactly what winter run are, nor why they are endangered.
Like all salmon, winter run reproduce (spawn) in freshwater. Their offspring migrate to the ocean as juveniles, where they feed and mature before returning to their natal stream to renew the cycle.
However, the timings of these movements differ dramatically among salmon species and populations. Winter run exhibit a suite of behaviors so unique that they are treated as a separate “species” by the Endangered Species Act (ESA) and were the first Pacific salmon to be state and federally listed as endangered in 1989 and 1994, respectively.
To help protect this endangered fish during freshwater residence, most of the Sacramento River has been designated as “critical winter run habitat” by the ESA. While winter run juveniles have occasionally been observed in intermittent streams and tributaries to the Sacramento River, no one knew how frequently they showed up, how long they stayed, nor whether these “errant teens” survived to tell the tale.
In a new study published this week in Biological Conservation, researchers from the Metropolitan Water District of Southern California, UC Davis Center for Watershed Sciences, NOAA Fisheries, and Lawrence Livermore National Laboratory used salmon otolith (“earstone”) chemistry to reveal the migration patterns and secret hang out spots used by juvenile winter run on their way to the ocean.
Read the full article.