Last year was a phenomenal year for salmon in California — and 2025 is already shaping up to be another banger twelve months for these fish.
Salmon are among the most ecologically important aquatic life known to science. Their migratory patterns, coupled with their sheer size, make them an important keystone species, having a disproportionately important impact on environments where they’re found.
(Brown and black bears rely on their flesh to make it through winter, and countless other animals gorge on them as well; salmon fry help keep pests in check by consuming their aquatic larvae; mating pairs building their nests agitate river and creek beds, allowing for organic material to re-enter the waterway; adult salmon that perish and remain uneaten and bits of unconsumed salmon flung around by carnivorous fertilize forest beds, riparian ecosystems, and other habitats; without hyperbole, the list truly goes on and on [and on].)
The removal of the Klamath River dams has allowed populations of chinook salmon — among the rarest salmon species on earth — to return to historic spawning grounds. When the water barricades were removed in July of last year, scientists began monitoring fish migratory patterns into the areas formerly inaccessible to them.
Many native species, including sturgeons and trout, have been documented moving through the area in high numbers, showing signs of rewilding and ecological recovery. Among the species observed, members of California Trout, a nonprofit organized around ensuring healthy water conditions for the state’s native fish species, were particularly elated to learn over 6,000 chinook salmon were found passing through the former Iron Gate Dam site.
“The Numbers are In: Our preliminary data shows over 6,000 salmon returned to their ancestral waters in the Klamath River between Oct. 17 and Oct. 29, 2024,” reads a post from the nonprofit on Instagram. Since the dam removal, these magnificent fish are reclaiming 400 miles of newly reopened habitat.”
According to the nonprofit, SONAR cameras installed at the site allowed scientists to capture” continuous video-like imagery” of the fish moving through. Upon further inspection, scientists learned the vast majority of these fish —some 98% of them — were either sexually mature adults or older sub-adult fish, measuring over 20 inches long.
“An estimated 221 to 588 fish pass through daily during this period,” reads a blog post for CalTrout highlighting the news. “The SONAR provided the first evidence of salmon reclaiming newly reopened habitats just days after dam removal construction was completed.”
The four dams were removed from the Klamath River last year, which flows through areas of Northern California and Southern Oregon, and remains the largest dam removal project in U.S. history. Constructed between the early to late-1900s, these dams were essential in generating electricity for surrounding urban and rural areas. However, as technologies and infrastructures matured and grew, countless electrical dams like these became unnecessary. It’s estimated around 85% of nearly the 100,000 dams constructed in the country are now useless — and, thus, could be removed without concerns about utility needs and better the ecosystems they impact.
“Working alongside our Tribal Nation partners, agencies, and fellow conservation organizations, we’re witnessing a watershed moment in river restoration,” continues the nonprofit on Instagram, underscoring the collaborative effort behind the project. “These fish are revealing what’s possible when we remove barriers!”
Feature image: Courtesy of CalTrout via Michael Wier
