The Park fire is tearing through some of California’s last wild habitat for threatened salmon

SACRAMENTO, Calif. — The devastation caused by wildfires extends far beyond human homes. Northern California’s Park Fire has burned through some of the Central Valley’s last wild salmon habitat, dealing a blow to an already struggling iconic fish species.

It’s unclear how much damage the fire has done to the Mill and Deer creek watersheds. But scientists fear that spring-run Chinook salmon, a once abundant California fish, could take another step toward extinction amid dangerous levels of population decline.

Last year California’s Department of Fish and Wildlife counted only 167 of the fish in the Central Valley’s Sacramento and San Joaquin river systems that were home to tens of thousands of them as recently as the early 2000s.

“You have this wildfire impacting, potentially greatly impacting their habitat at a time when their numbers are extremely low,” said Matt Johnson, a senior environmental scientist with the California Department of Fish and Wildlife. “Will that be the final death blow to the species? Probably not, but it’s another setback, especially if it’s a high intensity burn.”

The Central Valley is home to four major runs of Chinook salmon that are genetically different from one another, specifically in the gene that controls the timing of their migratory life span.

They were once extremely abundant, but Mill and Deer creeks are some of the last spawning habitat for spring-run Chinook salmon. Scientists and experts attribute population declines over the last century to a combination of factors.

Dams on most of California’s major rivers have blocked their passage to reach high-altitude spawning grounds, water diversions for agriculture and cities have narrowed their available habitat, and severe droughts worsened by climate change play a role.

Now spring-run salmon in the Central Valley rely mainly on Mill and Deer creeks, which are respectively being burned and under threat of burning in the state’s fourth-largest wildfire on record.

After a few mellow days, the Park Fire picked up in intensity in some areas this week including in the Mill Creek Canyon near Mineral in Tehama county. The blaze has burned across a 420,000 acre perimeter and is now 34% contained.

Hotter and drier conditions fueled the fire, which was sparked by alleged arson, deeper into the northeast portion of the fire over the last 48 hours, said officials.

The salmon that arrived this spring are likely swimming in deep pools along the creeks, where they are expected to spawn and lay their eggs in gravel underneath clear, cold stretches of water in late September and October.

These particular fish, which authorities haven’t yet been able to observe, are no strangers to adversity. They were hatched during the last years of the state’s most recent severe drought and have returned back to fresh water after maturing in the ocean.

Spring-run Chinook were listed as threatened under the federal Endangered Species Act in 1999. Scientists worry that this latest blow, depending on the fire’s severity, could push them over the edge to endangered.

“So many of our species are isolated in these stronghold pockets. When they’ve been depleted down to these ultra low levels, then you’re looking at vulnerability to an extinction event,“ said Andrew Rypel, a professor of fish ecology and director of UC Davis’ Center for Watershed Sciences.

Regardless of the outcome of this fire, he hopes those who aren’t anglers or wildlife enthusiasts recognize the value of this species. They were central to the lives of both Indigenous people and European settlers of the state, he said, feeding us with marine derived nutrients and fertilizing the forest.

“I don’t think people realize just how important this run of salmon was to the history of California,” Rypel said. “We are very close to losing this species”

He and other experts are holding their breath until they can assess the damage to the creek from the fire, which could be moderate or severe. While low intensity fires can bring ecosystem benefits, a destructive blaze would send harmful ash and soil into the creeks.

California Fish and Wildlife scientist Johnson called for more prudent and robust forest management. This particular fire could have been thwarted, experts said, if the city of Chico had enough resources to execute one last prescribed burn.

The salmon are adapted to survive through California’s natural cycles of fire, but their already low numbers combined with bigger, more destructive fires now make for a potentially lethal mix.

“These are wildfire ecosystems,” Johnson said. “Fish have evolved with wildfire but we have extreme wildfire now. We have to accept that and figure out ways to really mitigate it.”