The rivers and bays of Southern California were once filled with large, silvery fish that came from the ocean and swam upstream to spawn. But today these fish are rarely seen.
Southern California steelhead trout have been pushed to the brink of extinction as their river habitats have been altered by development and fragmented by barriers and dams.
Their numbers have been declining for decades, and last week the California Fish and Game Commission voted to list the Southern California steelhead trout as endangered.
Conservation advocates said they hoped the designation would accelerate efforts to save the fish and the aquatic ecosystems on which they depend.
“Historically, thousands of these fish swam in the rivers and streams of Southern California,” said Sandra Jacobson, director of the South Coast region of California Trout, an organization that advocated for the listing.
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“Their numbers have declined alarmingly due to habitat loss, fragmentation and the effects of urbanization,” Jacobson said. “This historic decision provides extremely important protections for this iconic species.”
The specific population of Southern California is one of eight types of steelhead trout in the state. They live in coastal waters and rivers from southern San Luis Obispo County to around the US-Mexico border.
steelhead trout are Similar species to rainbow trout, Oncorhynchus mykissBut unlike their freshwater relatives, steelheads They spend most of their lives feeding in the sea And return to their birthplace to lay eggs.
Steelhead typically grow to 2 or 3 feet and sometimes larger.
An adult steelhead trout in the San Luis Rey River in northern San Diego County.
(California Department of Fish and Game)
When winter and spring rains cause strong flows in rivers and creeks, fish migrate upstream. They travel to spawning habitats up to 30 miles inland – unless they encounter an obstacle along the way.
unlike salmon, which are part of the same familySteelheads often spawn several times before dying.
Southern California Steelheads were once upon a time caught by indigenous people, In the early 20th century, fishermen discovered that the fish were Abundant In the Ventura and other rivers.
But over the past century, the Los Angeles River and other waterways were littered with concrete. Coastal marshes were engulfed by development, and barriers and dams fragmented streams.
Southern California’s steelhead population was declared endangered by the federal government in 1997. Review Federal and state agencies have found that the population has continued to suffer since then.
“The negative trend toward extinction has not been reversed,” Jacobson said.
in 2020 StudyResearchers found that there had been only 177 documented sightings of Southern California steelhead over the past 25 years.
California Trout submitted a petition in 2021 urging the state to list the steelhead population as endangered.
Small numbers of fish continue to return to the Santa Clara and Santa Ynez Rivers, as well as Malibu Creek, Topanga Creek, and other rivers from Santa Barbara to San Diego counties.
Jacobson and other conservationists are advocating for accelerating plans to remove obsolete dams that impede fishing, including Matilija Dam in the Ventura River watershed and Rindge Dam In Malibu Creek Canyon. They are also demanding expediting the removal of barriers at Trabuco Creek and the Santa Margarita River.
Jacobson said other efforts to help steelhead trout include removing non-native species, reducing water diversions and groundwater pumping to ensure adequate flow in streams, and restoring the watershed’s natural ecosystem.
“Southern steelhead are important indicators of watershed health,” Jacobson said.
He said restoring the “aquatic highways” that fish use to reach their spawning habitats would also benefit people, including protecting sources of clean drinking water.
“I am optimistic about the recovery of steelhead,” Jacobson said. Classifying California’s population as endangered will help advance state conservation planning and add urgency to the removal of barriers to rivers, he said.
Steelhead trout living in Southern California face other threats, including warmer waters and more intense dry And Forest fire as a result of Climate change,
“These are the populations that are experiencing the hottest conditions, really at the forefront of the impacts of climate change. And then you layer on top of that how densely populated Southern California is,” said Andrew Rippel, professor of fish ecology and director of the UC Davis Center for Watershed Sciences. “All these steelhead streams in Southern California are extremely impacted.”
He said with so many factors weighing against steelhead trout, added protection can make a significant difference.
“This is the most challenging fish conservation issue I can imagine,” Rypel said. “How do you manage the entire landscape for fish conservation in the middle of one of the largest urban areas in the world? It is very challenging.”
This population of steelhead is effectively “a reversal of time,” he said.
He said it is important to remove barriers to breeding areas.
“It’s a really nice fish. This is a Southern California fish, and it’s up to the people of the area to keep an eye on it and make sure that future generations can see and protect this magnificent fish – and by doing so, protect the ecosystem. Do it.”
