Humboldt's Salmon Runs: Where and When to Witness the Return

A salmon run is the mass upstream migration of adult Pacific salmon from their ocean feeding grounds to the freshwater streams where they were born, arriving to spawn and — in all species except steelhead — to die. In Humboldt County, California, this migration moves across four major river systems from late July through early spring, depending on species and watershed. It constitutes the county's longest continuous wildlife spectacle, drawing bald eagles, black bears, ospreys, harbor seals, river otters, and an attentive category of observer who has learned that the river in October is worth keeping a calendar note.

Lady Humboldt considers the salmon run to be among the more consequential events in the county's annual schedule. The salmon, for their part, appear to agree, and are not taking questions about it.

Three salmonid species make sustained runs through Humboldt County's waterways each year. Each arrives on a schedule that is regular enough to plan for and variable enough to reward patience over certainty.

Chinook salmon (Oncorhynchus tshawytscha), also called king salmon, are the largest and the first to arrive. The fall run on the Klamath, Trinity, and Eel River systems begins in late July and August; the main pulse peaks between September and November. Adult Chinook in Humboldt County rivers typically weigh 15 to 40 pounds. The Klamath system historically supported one of the largest Chinook populations on the Pacific Coast, a fact that makes the river's twentieth-century decline and current restoration effort one of the more carefully watched ecological stories in California (NOAA Fisheries, 2025).

Coho salmon (Oncorhynchus kisutch), also called silver salmon, run later and in smaller numbers. On the Klamath and Mad River systems, coho begin appearing in earnest in November and continue through January in good water years. Coho are listed as threatened under the federal Endangered Species Act in the Southern Oregon/Northern California Evolutionarily Significant Unit, which includes all Humboldt County drainages (NOAA Fisheries, 2024). Their return is a quieter event than the Chinook run and, for observers who arrive in November when the tourist traffic has dispersed, a more intimate one.

Steelhead (Oncorhynchus mykiss) — technically a seagoing rainbow trout rather than a true Pacific salmon — differ from the other two species in one significant respect: they survive spawning and may return to the ocean to repeat the cycle in subsequent years. Humboldt County rivers support winter-run steelhead from November through March and, in the Trinity River system, a summer-run population that enters fresh water between June and August. Lady Humboldt notes that the distinction between a steelhead and a salmon is the sort of distinction that matters considerably to the fish.

Sources: California Department of Fish and Wildlife, 2025; NOAA Fisheries, 2024; Yurok Tribe Fisheries Department, 2025.

What brings an adult Chinook salmon back to within meters of its birth site after two to four years at sea is, in broad outline, well understood — and in its specifics, still a matter of ongoing research.

The navigational sequence is multi-stage. In the open ocean, salmon use the earth's magnetic field to locate the general vicinity of their home coast — a mechanism confirmed through displacement experiments in which fish fitted with magnetic-field-altering devices were shown to reorient consistently relative to the field manipulation (Putman et al., Current Biology, 2014). As the fish approaches the coast and enters the river's freshwater plume, olfactory detection takes over: the precise chemical signature of the home watershed, imprinted during the smolt stage before the fish first went to sea, draws the fish upstream with a reliability that has impressed researchers and complicated dam engineers for generations.

The transition from salt water to fresh water is a physiological event as much as a geographic one. Salmon that have spent years in seawater must recalibrate their kidneys, shift their metabolism from feeding to reproduction, and — in the case of the true Pacific salmon — begin the cellular breakdown that culminates in death after spawning. The fish stops eating when it enters fresh water; it is running on reserves accumulated over months of ocean feeding. By the time a Chinook reaches its spawning gravel, it may have traveled hundreds of miles upriver over several weeks without a meal, a schedule that Lady Humboldt considers one of the more committed approaches to any objective in the natural world.

The Klamath River — the second-largest river in California by volume, and the single most important salmon river on the North Coast — provides the most dramatic and most accessible fall run viewing in Humboldt County and the adjoining Del Norte County corridor.

The Klamath River Overlook Trail, reached via Requa Road from the town of Klamath (approximately 60 miles north of Eureka on Highway 101), climbs to a 340-foot headland above the river mouth and provides a view of the estuary, the tidal bar, and in fall, the surface activity of fish holding in the brackish zone before committing to the upstream passage. This trail is within Redwood National and State Parks; no entrance fee is charged at this trailhead. The overlook is best in morning light.

For river-level viewing, the Highway 101 bridge over the Klamath offers a vantage from the bridge rail — a less considered experience than the overlook but one that places the observer at water level during peak flow. The river below runs 200 to 400 yards wide at this crossing; fish are visible in low-light conditions when the water carries moderate turbidity and fish are concentrated in the shallower riffles approaching the bridge.

The best Klamath viewing window is typically the second and third weeks of October, when water levels drop to a level that concentrates fish in deeper channel pools and makes their presence legible from the bank. Rain years shift this timing forward; in drought years, low flows stress the fish and compress the visible run period substantially (Yurok Tribe Fisheries Department, 2025). A first fall rain event — typically in September or October — triggers a pulse of fish that had been staging offshore or in the estuary, and the week immediately following a significant rain is worth attention.

The Trinity River, entering the Klamath near Weitchpec after draining 3,000 square miles of interior mountain terrain, carries a substantial fall Chinook run visible along its lower canyon. California Highway 299 parallels the Trinity from Willow Creek to Burnt Ranch and beyond, crossing the river at points where gravel bars and deep pools collect fish during their upstream passage. The Burnt Ranch Gorge area on Highway 299, approximately 35 miles east of Willow Creek, provides access to a riverside vantage above a run of rapids that fish must negotiate — a situation that compresses fish into observable concentrations. Lady Humboldt notes, without elaboration, that this stretch of river repays a midweek visit in October.

The Van Duzen River, a tributary of the Eel entering near the town of Fortuna, carries a coho run historically significant enough to anchor ongoing restoration work by the Humboldt County Resource Conservation District. The Van Duzen confluence with the Eel is accessible from Fortuna; upstream reaches along County Road 512 offer bank access in good water years. The coho run here typically peaks in December, which is among the quieter months for human traffic along the river.

Redwood Creek, which drains the interior of Redwood National Park south of Orick, supports a designated wild coho population of conservation importance. The lower reach, accessible from the Davison Road corridor and from the beach at Gold Bluffs, carries coho from November through January. Visitor numbers in this stretch are low outside of summer, which is among the practical advantages of the November window. The hike directory lists trail access for the Tall Trees and Redwood Creek corridor area. Roosevelt elk, which use the Redwood Creek bottomland through the winter, are a common accompaniment to any November visit in this corridor — the Roosevelt elk guide covers the seasonal patterns in detail.

The salmon run does not arrive unaccompanied. It constitutes a supply chain that appears by river and is immediately noted by most of the county's major predators.

Bald eagles (Haliaeetus leucocephalus) concentrate on productive salmon rivers during the fall run in numbers visible from the road. The lower Klamath and lower Trinity regularly produce counts of 20 to 40 eagles within a few miles of river corridor in October and November — perched on riverside snags, hunting from low flight over the water, and competing, with considerable noise and no apparent dignity, for carcasses along the gravel bars. The birding guide covers the raptor concentration windows in more detail; the short version is that the salmon run is the event that concentrates more bald eagles in one visible place than any other single phenomenon in the Humboldt calendar.

Black bears (Ursus americanus) are reliable fall observers of the salmon run along tributaries with accessible bank. The coastal black bears of Humboldt County have learned to fish in the manner documented across the salmon range — standing in shallows or at pool edges, intercepting fish at moments of disadvantage. Bears that have located a productive salmon pool are not difficult to find; they tend to return to the same stretch of water on successive days, as is their custom. Standard precautions apply: distance and awareness, and an understanding that a bear extracting salmon from a river is engaged in work of considerable consequence to that bear and has no particular interest in the observer's itinerary.

Harbor seals (Phoca vitulina) push well into tidal reaches of the Klamath and Eel during fall runs, following the fish. Northern river otters (Lontra canadensis) work smaller tributaries. Great blue herons post themselves at the edges of shallow riffles, as is their custom, and wait. Ravens and crows arrive at carcasses within hours of their appearance on exposed gravel. The spectacle is not limited to the fish.

The salmon run does not end when the fish spawn and die. It continues, more quietly, for months afterward, as the carcasses that accumulate along gravel bars and in shallow back-channels decompose and enter the watershed's nutrient cycle.

Pacific salmon spend years in the ocean accumulating marine-derived nitrogen, phosphorus, and calcium from the deep food web. When they die in fresh water, those nutrients enter the stream system and — more importantly — the riparian forest. Stable isotope analysis has traced marine-derived nitrogen from salmon carcasses into the tissues of streamside plants, into soil fungi, and into the annual growth rings of conifer trees within several hundred meters of productive salmon streams. Trees growing beside salmon-bearing rivers carry measurably higher foliar nitrogen concentrations derived from marine sources than trees of the same species growing beside fishless streams of identical geology (Helfield and Naiman, Ecology, 2001; Gende et al., BioScience, 2002). The redwood trees along Redwood Creek are, in this specific sense, partly made of ocean.

The animals that move this nitrogen from carcass to forest include the bears and eagles mentioned above but also mink, ravens, crows, and a substantial biomass of invertebrates that colonize carcasses within hours of their appearance. The nutrient pulse from a productive fall run can be measured in streamside vegetation growth the following spring — a connection between two seasons that is not visible to the casual observer but that the forest registers, as is its custom, without comment.

The removal of four hydroelectric dams on the Klamath River, completed in late 2024, reopened approximately 420 miles of spawning and rearing habitat to anadromous fish for the first time in more than a century. In November 2024, Yurok Tribe biologists confirmed Chinook salmon spawning above the former Iron Gate Dam site — the first such observation since the early twentieth century.

The full recovery of salmon populations in the newly accessible Klamath headwaters is a decade-long process contingent on sediment stabilization, riparian vegetation establishment, and the gradual expansion of wild fish into unfamiliar habitat. The dam removal and salmon restoration post covers this story in detail. For present purposes: the Klamath's salmon run, measured in returning adult fish, is expected to increase substantially over the next two decades, and observers arriving at the Klamath Overlook in the 2030s may be watching a run of a scale not seen on this river within living memory. These facts may be related to the current restoration investment. Lady Humboldt declines to speculate on the timeline.

Sources: California Department of Fish and Wildlife, 2025; NOAA Fisheries North Coast, 2024; Yurok Tribe Fisheries Department, 2025. Timing varies by water year; earlier rains produce earlier runs.

River conditions during and after storms can render bank access unsafe and fish invisible in turbid water. A window of two to four days after a significant rain event — when the river drops to a fishable but not flood-stage level and turbidity clears — typically produces the most observable conditions. Lady Humboldt recommends checking USGS stream gauge data for the relevant watershed before making the drive, a precaution that requires no special expertise and saves considerable disappointment.

Lady Humboldt's weekly field guide arrives Tuesday mornings with notes on which rivers are running, what the salmon are doing, and what else the county is up to in any given week. It is written by a correspondent who walks the same river banks where the eagles are stationed. A subscription is here, and it is free. The newsletter archive holds accounts of previous fall runs, for those interested in the historical record.