Science. California's disappearing salmon in the face of climate change.

By Scott Wilson, The Washington Post.


California's disappearing salmon in the face of climate change.

Helltown, California is a quiet place set above a gentle swerve in Butte Creek, just an old span of bridge, some rusted-out mining equipment manufactured before this state was officially a state, and a seldom-used house.

But the harsh reality becomes apparent quickly, a smell on a hot, thin wind.

It is the stench from piles of rotting Chinook salmon carcasses on the creek banks and from the upside-down bodies of others snagged, already dead, on the creek's pale rocks.

For centuries, spring-run Chinook salmon, among California's most iconic fish, would rest for weeks in these historically cold waters after their brutal upstream journey. Then they would lay eggs and, finally, perish to complete one of nature's most improbable life cycles.

No longer. What once was a place where life began is now one of untimely death.

The creek is simply too warm, an astounding 10 degrees warmer than average in some parts of these spawning grounds. It is the result of the creek's low flow, which speeds up the spread of disease as the water stagnates, and of the Central Valley's high heat in the depths of drought.

Of the estimated 16,000 spring-run Chinook that made the journey from the Golden Gate Bridge to this curve in a creek and others like it across the Central Valley, about 14,500 have died, nearly all of them before spawning. More will succumb in the next few weeks, and a year of spring-run Chinook reproduction will be lost in the valley's hot, low-flow waterways. The conditions are threatening the winter migration, or "run," just as severely. And while it is still too early to measure the drought's effect on a pair of fall migrations, experts worry it could be just as disastrous.

"This year has been huge in terms of pre-spawn mortalities," said Colin Purdy, the state Department of Fish and Wildlife's environmental programs manager for fisheries based in the city of Chico. "This fall we'll just hope to see enough juveniles get out to sustain the population, and we need enough adults to survive to help us avoid a failed class."

The drought is enveloping much of the American West, where many places recorded their hottest July in history last month. The parched-brown landscape has become more normal than aberration in California, where the increasingly rapid shifts from cool to hot, wet to dry, are driving historically huge wildfires, deadly mudslides and new demands on water supplies.