This is an interesting subject. As a life-long Californian this caught my eye

For northern California (where most of its salmon rivers are located), cooler and wetter winter/spring conditions are typically the best for California salmon. Although precipitation is not well correlated with ENSO in Northern California, there are El Niño winters like 1982-83 and 1997-98 where northern California had exceptional rainfall and a big snowpack, and wetter years are typically good for California salmon spawning, rearing, and migrating conditions. But the warming of the California Current System that often comes with El Niño is typically bad for all West Coast salmon, including those in California.

I know precip is never completely aligned with ENSO, seems over the past fifty years La Nina has favored dry winters in California. The last three La Ninas have resulted in statewide dry conditions in California that have affected California's population. But so did the unusually wet 2016/2017 La Nina year. It also seems in recent years ENSO has not been consistent in its rainfall in the PNW. Seems some of the PNW has been drier than normal during these consecutive La Nina years. And with the FY15/16 Super EL Nino, the precipitation patterns completely flipped from the expected precip patterns from the PNW down through CA. Salmon has been a big issue in California and a major part of our water wars.