Emily Funk, an associate specialist at the University of California Davis, collects a mucus sample from...
Emily Funk, an associate specialist at the University of California Davis, collects a mucus sample from a Chinook salmon to determine its exact species while on a research vessel on the San Joaquin River off Antioch, California, U.S., May 25, 2021. Picture taken May 25, 2021. REUTERS/Nathan Frandino