2024 Fall Salmon Redd Survey Results Reinvigorate Commitment to Instream Habitat Restoration

“Do you see that white tail flashing?”

Cindy Buxton, Aquatic Program Manager, has worked in fisheries for more than a decade. Her keen eyes are especially attuned to spot salmon from the somewhat challenging vantage point of her inflatable kayak. “They stop eating and their skin can’t fight the various fungi that begin to grow on their heads and tails. It makes them easier to see through the water.”

The South Fork Trinity River is a dynamic ecosystem that changes every year. One year’s spawning ground may have too much or too little sediment for salmon to lay their eggs the following year. Annual redd (salmon nest) surveying allows Watershed Center fisheries staff to track changes in habitat and salmon populations and design projects to support river and fish health. 

Rainstorms preclude surveying by raising the water level in the river. Conditions need to be favorable to get accurate fish and redd counts.

“The gravel of a redd is lighter because as the female digs with her tail, the gravels are tumbled, exposing the underside with no algae,” Cindy explains. “Then you can see the oblong bowl-like depression, tapering downstream.” Some redds are merely test redds, incomplete and shallow, belying the salmon’s experimentation with water flow and gravel texture. Other redds are fully formed in an ideal location–often a riffle where the river runs fast and straight–churning oxygen into the water.

Salmon are anadromous fish. They hatch in freshwater, grow to adulthood in the ocean, and return to their natal streams to reproduce and perish. Their bodies, rich with nitrogen and phosphorus accumulated during their time at sea, then fertilize and nourish plants and animals in the freshwater river systems where they return to spawn before dying. 

Salmon are extremely culturally significant to many Native American tribes that honor the salmon’s sacred place in the ecosystem through art, stories, songs, and ceremony. Salmon are truly a keystone species–their influence on the environment around them is large compared to their population size. To lose these fish would create cascading effects throughout the entire ecosystem.

This year, Watershed Center fisheries staff conducted a number of surveys counting: 104 live salmon, 4 dead salmon, and 61 redds. The South Fork Trinity River spring Chinook population has reached historic lows and fall run Chinook numbers are also dwindling.

“When these tiny alevin hatch from their eggs, they only have about a 5% survival rate. When you hear that a salmon lays a million eggs it seems like there would be plenty of fish, but almost none of those salmon reach the ocean, grow up, and return to spawn themselves. Only a tiny fraction of those eggs will result in adult salmon able to reproduce. In order to reach adulthood they need cold water, plenty of insects to eat, and diverse habitat where they can hide to avoid being eaten themselves. If and when they reach the ocean, they face much larger predators, harsh ocean conditions, and commercial fishing,” Cindy shares. 

Our local salmon populations are at historic lows. From runs in the 1800s so large people could walk across the river on the backs of these fish, to current populations where we are observing tens, or at best, hundreds of individual fish, we are struggling to regain this critical species.  Instream habitat restoration remains one of our best tools to help increase salmon populations. By making conditions favorable for fish, more will grow large enough to survive in the ocean and return to spawn, starting the cycle anew.

It can be difficult for the untrained eye to spy every fish during surveys. It’s important to get the next generation of fish stewards out on the water to make their own observations and hone their skills.

While we work to support the fish in their life cycle, we are also paying attention to humans’ role and the next generation of fish stewards. This fall we had the opportunity to bring Trinity High School students out to the river to help with data collection.Training the next generation of fisheries technicians is another action we can take to support this keystone species into the future.

The Watershed Center, in partnership with the Karuk, Yurok, Nor-Rel-Muk Wintu, and Hoopa tribes, as well as agencies such as the Trinity River Restoration Program, U.S. Forest Service, California Department of Fish and Wildlife, and Trinity County Resource Conservation District, remains committed to advocating for these fish by educating the public, implementing restoration projects, and adapting management strategies as conditions change.

The cover photo for this blog was captured by Nathan McCanne, former Fisheries Technician.