Reflecting on the 2024 Cooperative Salmon River Spring Chinook & Summer Steelhead Census Dives

Divers survey the North Fork Salmon River for Spring Chinook and Summer Steelhead. Photo by Amber Jamieson.

In collaboration with agencies, Tribes, non-profit organizations and volunteers, the Salmon River Restoration Council (SRRC) has been conducting the “Cooperative Salmon River Spring Chinook and Summer Steelhead Census Dives” since 1992, making the dataset the longest running survey of this kind for Pacific Northwest salmon. The data from these surveys is used to help estimate the status of wild salmon populations and inform harvest regulations for subsequent years.

On July 24, EPIC staff participated in the dives, and counted 3 adult spring Chinook and 1 adult steelhead on their 4-mile reach. Although the final numbers are not yet in, the preliminary numbers are quite low, which may result in continued fishery closures in the coming year. However, since spring Chinook aren't managed separately from fall Chinook, the low numbers don't specifically trigger any management changes aside from the fisheries closures triggered by the spawner floor of 30,000 total combined spring and fall spawners per year.

Fish dive participants receive instruction prior to surveying the river. Photo by Amber Jamieson.

Preliminary data for 2024 Cooperative Salmon River Spring Chinook and Summer Steelhead Census Dives compared with 2023 data. Photo by Amber Jamieson.

The Salmon River is a free-flowing Wild and Scenic River that is entirely within the Klamath National Forest. The headwaters originate in the high country of the Trinity Alps, Russian Mountains and Marble Mountain Wilderness Areas, which create incredible habitat for anadromous salmon, and serve as one of the last strongholds for Spring-run Chinook salmon, or “Springers,” in the Klamath Basin.

Springers migrate earlier in the year when the spring runoff provides an abundance of cold water from snowmelt for them to migrate earlier and higher up into the headwaters than their fall-run cousins. Once they get high up into these watersheds, they hole up for the summer in deep pools or in cold water refugia until their gametes mature, at which point they spawn from about September 15th to October 15th — about a month before the fall Chinook. After a century of mining, logging, dam building and other anthropogenic activities, Springer populations have plummeted, as it has become more difficult for them to survive the hotter, drier summer months.

Spring Chinook holding up at a creek mouth, which provides a cold water refugia for during hotter temperatures. Photo credit Nat Pennington.

With Klamath dam removal underway, Springers are of particular interest because they are the species that would repopulate the Upper Klamath River Basin. Genetic testing of ancient salmon bones found in caves of the Upper Basin have revealed that 85% originated from Springers, which confirms that they were once the predominant species in the Upper Basin.

A recent study from the Genetics Department at UC Davis has revealed that Springers are genetically different from fall Chinook. With the last few populations of spring Chinook hanging on by a thread, it is hoped that some will stray from their natal streams and help to repopulate the Upper Klamath River Basin, since they are the salmon that evolved in those places. If the Klamath’s last run of wild Springers on the Salmon River were to perish before repopulating the areas above the decommissioned dams, it is likely that these evolutionarily distinct populations of spring Chinook would take thousands of years to re-evolve.

Diver points out boulder sieves, which can be dangerous for surveyors. Photo credit Halle Pennington.