Rain might bring relief from wildfires searing Los Angeles County but could spell disaster for the only known population of Southern California steelhead trout in the Santa Monica Mountains.
The destructive Palisades Fire appears to have scorched the entirety of the state and federally endangered trout’s accessible habitat in Topanga Creek, a small coastal mountain stream that drains into the Pacific Ocean. But experts say the secondary effects of the fire are what pose the biggest existential threat.
A heavy storm following a blaze can sweep massive amounts of sediment and charred material from the denuded hillsides into the water they inhabit — a death trap for creatures that can’t flee.
“One of our biggest concerns is … losing that last population of fish,” said Kyle Evans, an environmental program manager for the California Department of Fish and Wildlife.
The state agency is already considering a potential rescue plan. But even if the fish survive, experts say, the increased frequency of wildfires in the region has lasting negative effects on aquatic life. And some believe the health of the fish is a mirror for that of our society.
Vulnerable populations of rainbow trout are also threatened by the Eaton Fire burning in the San Gabriel Mountains north of Los Angeles.
Steelhead trout are the same species as rainbow trout, Oncorhynchus mykiss, but unlike their freshwater-dwelling relatives, steelheads spend much of their lives feeding in the ocean and return to their natal streams to spawn.
Tens of thousands of the silvery fish once returned to Southern California streams every year, to the delight of anglers. They swam most streams of the Santa Monicas, which stretch from the Hollywood Hills to Point Mugu in Ventura County.
Historic photos show fishermen in the Malibu estuary and elsewhere pulling up stringers full of the hefty fish that can grow up to 2 feet, according to Russell Marlow, South Coast senior project manager for California Trout, a conservation group.
Then dams were erected in the region starting in the 1940s, and “that’s when we began to see a pretty precipitous decline in the population,” Marlow said.
A 2012 federal recovery plan reported that fewer than 500 adult Southern California steelhead return annually to natal waters located between southern San Luis Obispo County and the United States-Mexico border. It’s likely the figure is much lower today.
The distinct Southern California population was added to the California endangered species list last year.
With the population so depressed, “every fish counts,” Marlow said. He called the Topanga Creek population, which is well monitored, “extremely important.” The creek is home to 400 to 500 rainbows.
