Recent research highlights the significant impact of the dry winter of 2013-2014 on California's salmon and trout populations. A study published in the "Proceedings of the National Academy of Sciences" by biologists revealed that the unusually dry season caused some salmon and steelhead trout to temporarily vanish from certain tributaries and watersheds along northern California's coast.

Stephanie Carlson, University of California, Berkeley professor, stated, “California is at the southern end of the range for several species of salmon and trout, and because of a whole host of impacts, from colonization and engineered control of western rivers to climate change, these populations have been decimated.”

The study analyzed the effects of the drought on Chinook salmon, coho salmon, and steelhead trout, collectively known as salmonids, in 13 coastal watersheds from Marin to Humboldt counties. While all three fish species were affected, the Chinook salmon displayed resilience by adjusting their breeding locations downstream. However, steelhead trout and coho salmon suffered more severe consequences, with coho completely disappearing from three watersheds.

“In the decade since that drought, all three species have fully recovered their original ranges," Carlson noted, crediting species' lifecycle diversity and conservation efforts as pivotal factors.

Stephanie Carlson's team initiated the study after Suzanne Rhoades and Cleo Woelfle-Hazard noted missing juvenile steelhead and coho salmon during surveys. Carlson also spoke with Mariska Obedzinski from California Sea Grant, who observed similar patterns in the Russian River system. Carlson commented on discovering the broader phenomenon, “We were seeing juveniles missing, but also some observations of adults that had spawned at unusual times or in unusual places.”

“Partnerships like this between resource managers and academia are so important for salmon recovery,” said Obedzinski, emphasizing the necessity of long-term monitoring for understanding hydroclimatic impacts on salmon populations.

Mary Power, UC Berkeley Professor, emphasized understanding behavioral mechanisms enabling salmonids to survive at the southern range's edge is vital as climate change progresses. She explained, “These traits could be keys to salmon survival over much of their range on a warmer Earth.”

Additional co-authors include Kasey Pregler, Sean Gallagher, Nathan Queener, and Sally Thompson. The National Science Foundation, U.S. Army Corps of Engineers, NOAA-Fisheries, and others supported the research.